JP4655358B2 - Provider confirmation system and provider confirmation method - Google Patents

Description

【００６６】
次にＳ６０８において共通鍵暗号化部１１２により共通鍵Ｃ２を用いて秘密鍵Ｓ２を暗号化し、それを送信者Ａ側装置１０１に送信する。
【００６７】
送信者Ａ側装置１０１は、Ｓ６０９において共通鍵復号化部１０５により共通鍵Ｃ２を用いて登録局ＲＡ側装置１０８から受信した秘密鍵Ｓ２を復号化する。次にＳ６１０において署名生成部１０６により任意の関数を用いて電子文書Ｅのハッシュ値を算出し、それを秘密鍵Ｓ１を用いて暗号化してデジタル署名Ｇ１を生成するとともに、関数情報Ｆも秘密鍵Ｓ１を用いて暗号化する。そして、ＩＤ番号と暗号化されたデジタル署名Ｇ１と関数情報Ｆを電子文書Ｅに付加して受信者Ｂ側装置１２０に送信する。
【００６８】
次に署名確認処理時の動作について、図７を用いて説明する。図７は署名確認処理のフローチャートである。
【００６９】
受信者Ｂ側装置１２０は、送信者Ａ側装置１０１から電子文書Ｅとデジタル署名が送信された場合に、Ｓ７０１において公開鍵要求部１２１により認証局ＣＡに対して電子文書Ｅに付加されたＩＤ番号を送信して送信者Ａの公開鍵Ｐ１の提供を要求する。
【００７０】
認証局ＣＡ側装置１１５は、Ｓ７０２において受信したＩＤ番号により公開鍵データベース１１９に登録されている送信者Ａを特定し、送信者Ａの公開鍵P１を受信者Ｂ側装置１２０に送信する。
【００７１】
受信者Ｂ側装置１２０は、Ｓ７０３において認証局ＣＡ側装置１１５から送信者Ａの公開鍵Ｐ１を取得する。次にＳ７０４において補正情報要求部５０３により登録局ＲＡ側装置１０８に対して電子文書Ｅに付加されたＩＤ番号を送信して送信者Ａの補正情報Ｒ１の提供を要求する。
【００７２】
登録局ＲＡ側装置１０８は、Ｓ７０５において鍵補正情報提供部５０２により個人情報データベース１１４に登録されている送信者Ａの最新の補正情報Ｒ１を受信者Ｂ側装置１２０に送信する。この際、秘密鍵Ｓ２の再利用を防ぐため、補正情報提供部５０２は個人情報データベース１１４から補正情報Ｒ１を抹消する。
【００７３】
受信者Ｂ側装置１２０は、Ｓ７０６において登録局ＲＡ側装置１０８から補正情報Ｒ１を取得する。次にＳ７０７において公開鍵補正部５０４により公開鍵Ｐ１を補正する。なお、補正により得られる公開鍵Ｐ２は認証局ＣＡから取得した送信者Ａの公開鍵Ｐ１と登録局ＲＡから取得した送信者Ａの最新の補正情報Ｒ１を用いて以下の式２により算出したものである。
【００７４】
【数２】

【００７５】
次にＳ７０８において署名確認部１２２により算出した送信者Ａの公開鍵Ｐ２を用いて送信者Ａから受信した電子文書Ｅに付加されたデジタル署名Ｇ１を復号化して送信者Ａが算出したハッシュ値を取得するとともに、関数情報Ｆも送信者Ａの公開鍵Ｐ２を用いて復号化してそれにより特定された関数を用いて受信した電子文書Ｅのハッシュ値を算出し、２つのハッシュ値を比較する。これにより送信者がＡ本人であるであることを確認する。
【００７６】
以上説明したように、本発明の第２実施例によれば、署名生成処理時に登録局ＲＡが新たに秘密鍵Ｓ２を生成するので、過去の署名生成処理時に用いた秘密鍵を繰り返し使用することを防ぐことができる。そのため、秘密鍵の漏洩による第三者の不正利用（例えばなりすましなど）を回避することができる。その上、受信者Ｂは送信者Ａの公開鍵Ｐ１と補正情報Ｒ１とをそれぞれ別々の機関から取得する必要があるため、情報を暗号化・復号化させるプロセスの機密を厳重に秘匿することができ、システムのセキュリティを向上させることができる。
【００７７】
＜第３実施例＞
第３実施例は、秘密鍵の再利用を最大Ｎ回まで許す構成にしたものである。なお、これに合わせて補正情報提供部５０２はシステムの求めるセキュリティレベルや利用者の利便性などを考慮して適宜調整してある。
【００７８】
図１０は第３実施例の構成図である。第３実施例は、第２実施例に対し、登録局ＲＡ側装置１０８にアクセスカウンタ部１００１を加えたものである。
【００７９】
アクセスカウンタ部１００１は、登録局ＲＡ側装置１０８から送信者Ａ側装置１０１に提供した秘密鍵の回数や受信者Ｂ側装置１２０に提供した補正情報の回数を記録する部位である。
【００８０】
第３実施例の動作は、署名生成処理時に第２実施例と相違する。そこで、以下に、図１１を用いてこの動作について説明する。なお、図１１は署名生成処理のフローチャートである。
【００８１】
送信者Ａ側装置１０１は、初めにＳ１１０１において生体特徴取得部１０２により送信者Ａの生体特徴情報Ｄを取得する。次にＳ１１０２において共通鍵生成部１０３により共通鍵Ｃ２を生成する。なお、共通鍵Ｃ２は送信者Ａの利用者（送信者）登録処理時に用いた共通鍵Ｃ１と異なっても良いものであり、乱数などを用いることができる。次にＳ１１０３において公開鍵暗号化部１０４により登録局ＲＡの公開鍵暗号P０を用いて生体特徴情報Ｄと共通鍵Ｃ２を暗号化し、それを登録局ＲＡ側装置１０８に送信する。
【００８２】
登録局ＲＡ側装置１０８は、Ｓ１１０４において秘密鍵復号化部１０９により自身の秘密鍵Ｓ０を用いて送信者Ａ側装置１０１から送信された生体特徴情報Ｄと共通鍵Ｃ２を複号化する。次にＳ１１０５において本人確認部１１０により送信者Ａ側装置１０１から送信された生体特徴情報Ｄと個人情報データベース１１４に登録されている生体特徴情報Ｄとを照合して本人確認を行う。本人と確認された場合に、Ｓ１１０６において、アクセスカウンタ部１００１に記録されている送信者Ａの最新の秘密鍵Ｓ２を提供した回数が、所定回数内であるのかをチェックする。所定回数内であれば、Ｓ１１０７においてアクセスカウンタ部１００１に記録されているカウント数を１つアップさせて、動作をＳ１１１１に進める。所定回数を超えていれば、動作をＳ１１０８に進める。
【００８３】
Ｓ１１０８において秘密鍵・公開鍵生成部１１１により送信者Ａの秘密鍵Ｓ２と公開鍵Ｐ２を新たに生成する。これらの鍵は送信者Ａの登録時や前回の署名生成処理時に生成した秘密鍵や公開鍵と異なっていることが望ましい。次にＳ１１０９において補正情報生成部５０１により補正情報Ｒ１を生成し、個人情報データベース１１４に登録する。なお、補正情報Ｒ１は新たに生成した送信者Ａの公開鍵Ｐ２と個人情報データベースに登録されている送信者Ａの公開鍵Ｐ１を用いて以下の式３により算出したものである。また個人情報データベース１１４に登録する補正情報Ｒ１は常に最新のものだけとする。
【００８４】
【数３】

【００８５】
次にＳ１１１０においてアクセスカウンタ部１００１のカウント数を初期化、すなわち０にする。
【００８６】
次にＳ１１１１において共通鍵暗号化部１１２により共通鍵Ｃ２を用いて秘密鍵Ｓ２を暗号化し、それを送信者Ａ側装置１０１に送信する。
【００８７】
送信者Ａ側装置１０１は、Ｓ１１１２において共通鍵復号化部１０５により共通鍵Ｃ２を用いて登録局ＲＡ側装置１０８から受信した秘密鍵Ｓ２を復号化する。次にＳ１１１３において署名生成部１０６により任意の関数を用いて電子文書Ｅのハッシュ値を算出し、それを秘密鍵Ｓ１を用いて暗号化してデジタル署名Ｇ１を生成するとともに、関数情報Ｆも秘密鍵Ｓ１を用いて暗号化する。そして、ＩＤ番号と暗号化されたデジタル署名Ｇ１と関数情報Ｆを電子文書Ｅに付加して受信者Ｂ側装置１２０に送信する。
【００８８】
以上説明したように、本発明の第３実施例によれば、１回の本人確認で生成した鍵を、所定回数内に限り、複数の署名に利用できるため、一定水準以上のシステムのセキュリティを確保した状態で鍵を提供する速度を速めることができ、システムの利便性を向上させることができる。
【００８９】
＜第４実施例＞
第４実施例は、第３実施例では登録局ＲＡ側装置１０８が発行済み秘密鍵Ｓ２の流用回数を管理するのに対し、送信者Ａ側装置１０１が管理するように構成にしたものである。
【００９０】
図１２は第４実施例の構成図である。第４実施例は、第３実施例に対し、送信者Ａ側装置１０８に秘密鍵記憶部１２０１を加えたものである。
【００９１】
秘密鍵記憶部１２０１は、登録局ＲＡ側装置１０８から送信者Ａ側装置１０１に提供された秘密鍵Ｓ２を記録する部位である。送信者Ａ側装置１０１は、秘密鍵記憶部１２０１に記録された秘密鍵Ｓ２を流用してデジタル署名Ｇ１を生成することになる。なお、送信者Ａ側装置１０１は、署名生成部１０６により秘密鍵記憶部１２０１に記録された秘密鍵Ｓ２を流用した回数をカウントしている。そして、流用した回数が所定回数を越える場合に、送信者Ａ側装置１０１は、送信者Ａの生体特徴情報Ｄを取得してそれを登録局ＲＡ側装置１０８に送信し、登録局ＲＡ側装置１０８に送信者Ａの新たな秘密鍵Ｓ２を生成させる。
【００９２】
第４実施例の動作は、署名生成処理時および署名確認処理時に第３実施例と相違する。そこで、以下に、これらの動作について説明する。
【００９３】
まず、署名生成処理時の動作について、図１３を用いて説明する。図１３は署名生成処理のフローチャートである。
【００９４】
送信者Ａ側装置１０１は、初めにＳ１３０１において秘密鍵記憶部１２０１に記録されている送信者Ａの発行済みの秘密鍵Ｓ２を流用するのかを判断する。流用するのであれば、Ｓ１３０２において秘密鍵記憶部１２０１から送信者Ａの秘密鍵Ｓ２を読み出し、動作をＳ１３１４に進める。流用しないのであれば、動作をＳ１３０３に進める。
【００９５】
Ｓ１３０３において生体特徴取得部１０２により送信者Ａの生体特徴情報Ｄを取得する。次にＳ１３０４において共通鍵生成部１０３により共通鍵Ｃ２を生成する。なお、共通鍵Ｃ２は送信者Ａの利用者（送信者）登録処理時に用いた共通鍵Ｃ１と異なっても良いものであり、乱数などを用いることができる。次にＳ１３０５において公開鍵暗号化部１０４により登録局ＲＡの公開鍵暗号P０を用いて生体特徴情報Ｄと共通鍵Ｃ２を暗号化し、それを登録局ＲＡ側装置１０８に送信する。
【００９６】
登録局ＲＡ側装置１０８は、Ｓ１３０６において秘密鍵復号化部１０９により自身の秘密鍵Ｓ０を用いて送信者Ａ側装置１０１から送信された生体特徴情報Ｄと共通鍵Ｃ２を複号化する。次にＳ１３０７において本人確認部１１０により送信者Ａ側装置１０１から送信された生体特徴情報Ｄと個人情報データベース１１４に登録されている生体特徴情報Ｄとを照合して本人確認を行う。
【００９７】
本人と確認された場合に、Ｓ１３０８において秘密鍵・公開鍵生成部１１１により送信者Ａの秘密鍵Ｓ２と公開鍵Ｐ２を新たに生成する。これらの鍵は送信者Ａの登録時や前回の署名生成処理時に生成した秘密鍵や公開鍵と異なっていることが望ましい。次にＳ１３０９において補正情報生成部５０１により補正情報Ｒ１を生成し、個人情報データベース１１４に登録する。なお、補正情報Ｒ１は新たに生成した送信者Ａの公開鍵Ｐ２と個人情報データベースに登録されている送信者Ａの公開鍵Ｐ１を用いて以下の式４により算出したものである。また個人情報データベース１１４に登録する補正情報Ｒ１は常に最新のものだけとする。
【００９８】
【数４】

【００９９】
次にＳ１３１０においてアクセスカウンタ部１００１のカウント数を初期化、すなわち０にする。
【０１００】
次にＳ１３１１において共通鍵暗号化部１１２により共通鍵Ｃ２を用いて秘密鍵Ｓ２を暗号化し、それを送信者Ａ側装置１０１に送信する。
【０１０１】
送信者Ａ側装置１０１は、Ｓ１３１２において共通鍵復号化部１０５により共通鍵Ｃ２を用いて登録局ＲＡ側装置１０８から受信した秘密鍵Ｓ２を復号化する。Ｓ１３１３において秘密鍵Ｓ２を秘密鍵記憶部１２０１に記録する。次にＳ１３１４において署名生成部１０６により任意の関数を用いて電子文書Ｅのハッシュ値を算出し、それを秘密鍵Ｓ１を用いて暗号化してデジタル署名Ｇ１を生成するとともに、関数情報Ｆも秘密鍵Ｓ１を用いて暗号化する。そして、ＩＤ番号と暗号化されたデジタル署名Ｇ１と関数情報Ｆを電子文書Ｅに付加して受信者Ｂ側装置１２０に送信する。
【０１０２】
なお、以降の署名生成処理動作は、秘密鍵記憶部１２０１に記憶された秘密鍵Ｓ２を流用することで、Ｓ１３０３からＳ１３１３までの動作を省くことができる。この場合、秘密鍵Ｓ２を流用するのか、否か（すなわち、登録局ＲＡ側装置１０８に新規に生成させるのか）は、送信者Ａ側装置１０１が秘密鍵Ｓ２の流用回数に基づいて判断することになる。
【０１０３】
次に署名確認処理時の動作について、図１４を用いて説明する。図１４は署名確認処理のフローチャートである。なお、本実施例では、登録局ＲＡ側装置１０８は受信者Ｂ側装置１２０からの送信者Ａの補正情報Ｒ１の提供を要求回数をカウントしている。そして、要求回数が所定回数を越える場合に、登録局ＲＡ側装置１０８は、受信者Ｂ側装置１２０への送信者Ａの補正情報Ｒ１の提供を中止する。これにより登録局ＲＡ側装置１０８は、一定水準以上のシステムのセキュリティを確保している。
【０１０４】
受信者Ｂ側装置１２０は、送信者Ａ側装置１０１から電子文書Ｅとデジタル署名が送信された場合に、Ｓ１４０１において公開鍵要求部１２１により認証局ＣＡに対して電子文書Ｅに付加されたＩＤ番号を送信して送信者Ａの公開鍵Ｐ１の提供を要求する。
【０１０５】
認証局ＣＡ側装置１１５は、Ｓ１４０２において受信したＩＤ番号により公開鍵データベース１１９に登録されている送信者Ａを特定し、送信者Ａの公開鍵P１を受信者Ｂ側装置１２０に送信する。
【０１０６】
受信者Ｂ側装置１２０は、Ｓ１４０３において認証局ＣＡ側装置１１５から送信者Ａの公開鍵Ｐ１を取得する。次にＳ１４０４において補正情報要求部５０３により登録局ＲＡ側装置１０８に対して電子文書Ｅに付加されたＩＤ番号を送信して送信者Ａの補正情報Ｒ１の提供を要求する。
【０１０７】
登録局ＲＡ側装置１０８は、Ｓ１４０５において、アクセスカウンタ部１００１に記録されている送信者Ａの最新の補正情報Ｒ１を提供した回数が、所定回数内であるのかをチェックする。所定回数内であれば、アクセスカウンタ部１００１に記録されているカウント数を１つアップさせて、動作をＳ１２０６に進め、所定回数を越えていれば、送信者Ａの補正情報Ｒ１を提供できない旨を受信者Ｂ側装置１２０に送信する。
【０１０８】
Ｓ１４０６において鍵補正情報提供部５０２により個人情報データベース１１４に登録されている送信者Ａの最新の補正情報Ｒ１を受信者Ｂ側装置１２０に送信する。この際、アクセスカウンタ部１００１に記録されている送信者Ａの最新の補正情報Ｒ１を提供した回数が所定回数に達した場合には、秘密鍵Ｓ２の再利用を防ぐため、補正情報提供部５０２は個人情報データベース１１４から補正情報Ｒ１を抹消する。
【０１０９】
受信者Ｂ側装置１２０は、Ｓ１４０７において登録局ＲＡ側装置１０８から補正情報Ｒ１を取得する。次にＳ１４０８において公開鍵補正部５０４により公開鍵Ｐ１を補正する。なお、補正により得られる公開鍵Ｐ２は認証局ＣＡから取得した送信者Ａの公開鍵Ｐ１と登録局ＲＡから取得した送信者Ａの最新の補正情報Ｒ１を用いて以下の式５により算出したものである。
【０１１０】
【数５】

【０１１１】
次にＳ１４０９において署名確認部１２２により算出した送信者Ａの公開鍵Ｐ２を用いて送信者Ａから受信した電子文書Ｅに付加されたデジタル署名Ｇ１を復号化して送信者Ａが算出したハッシュ値を取得するとともに、関数情報Ｆも送信者Ａの公開鍵Ｐ２を用いて復号化してそれにより特定された関数を用いて受信した電子文書Ｅのハッシュ値を算出し、２つのハッシュ値を比較する。これにより送信者がＡ本人であるであることを確認する。
【０１１２】
以上説明したように、本発明の第４実施例によれば、送信者Ａ側装置１０１は、以前取得した鍵をデジタル署名Ｇ１の生成に流用する。そのため、送信者Ａ側装置１０１は、登録局ＲＡ側装置１０８と通信しなくてもよいので、第３実施例よりも早く電子的な情報を受信者Ｂ側装置１２０に提供することができる。
【０１１３】
＜第５実施例＞
第５実施例は、秘密鍵の再利用を所定時間内に限って許す構成にしたものである。なお、これに合わせて補正情報提供部５０２はシステムの求めるセキュリティレベルや利用者の利便性などを考慮して適宜調整してある。
【０１１４】
図１５は第５実施例の構成図である。第５実施例は、第３実施例に対し、アクセスカウンタ部１００１の代わりに時間記録部１５０１を設けたものである。
【０１１５】
時間記録部１５０１は、登録局側ＲＡ装置１０８から送信者Ａ側装置１０１に秘密鍵を生成した時間や提供した時間、受信者Ｂ側装置１２０に補正情報を提供した時間等を記録する部位である。
【０１１６】
第５実施例の動作は、署名生成処理時に第３実施例と相違する。そこで、以下に、図１６を用いてこの動作について説明する。なお、図１６は署名生成処理のフローチャートである。
【０１１７】
送信者Ａ側装置１０１は、初めにＳ１６０１において生体特徴取得部１０２により送信者Ａの生体特徴情報Ｄを取得する。次にＳ１６０２において共通鍵生成部１０３により共通鍵Ｃ２を生成する。なお、共通鍵Ｃ２は送信者Ａの利用者（送信者）登録処理時に用いた共通鍵Ｃ１と異なっても良いものであり、乱数などを用いることができる。次にＳ１６０３において公開鍵暗号化部１０４により登録局ＲＡの公開鍵暗号P０を用いて生体特徴情報Ｄと共通鍵Ｃ２を暗号化し、それを登録局ＲＡ側装置１０８に送信する。
【０１１８】
登録局ＲＡ側装置１０８は、Ｓ１６０４において秘密鍵復号化部１０９により自身の秘密鍵Ｓ０を用いて送信者Ａ側装置１０１から送信された生体特徴情報Ｄと共通鍵Ｃ２を複号化する。次にＳ１６０５において本人確認部１１０により送信者Ａ側装置１０１から送信された生体特徴情報Ｄと個人情報データベース１１４に登録されている生体特徴情報Ｄとを照合して本人確認を行う。本人と確認された場合に、Ｓ１６０６において、現在の時刻が時間記録部１３０１に記録されている送信者Ａの最新の秘密鍵Ｓ２を生成した時間から所定時間内であるのかをチェックする。所定時間内であれば、動作をＳ１６０９に進める。所定時間を超えていれば、動作をＳ１６０７に進める。
【０１１９】
Ｓ１６０７において秘密鍵・公開鍵生成部１１１により送信者Ａの秘密鍵Ｓ２と公開鍵Ｐ２を新たに生成する。これらの鍵は送信者Ａの登録時や前回の署名生成処理時に生成した秘密鍵や公開鍵と異なっていることが望ましい。次にＳ１６０８において補正情報生成部５０１により補正情報Ｒ１を生成し、補正情報Ｒ１を個人情報データベース１１４に登録する。なお、補正情報Ｒ１は新たに生成した送信者Ａの公開鍵Ｐ２と個人情報データベースに登録されている送信者Ａの公開鍵Ｐ１を用いて以下の式６により算出したものである。また個人情報データベース１１４に登録する補正情報Ｒ１は常に最新のものだけとする。
【０１２０】
【数６】

【０１２１】
次にＳ１６０９において時間記録部１５０１に時刻を記録させる。このとき時間記録部１５０１は、、動作がＳ１６０６から進んだ場合であれば、送信者Ａの最新の秘密鍵Ｓ２を送信者Ａ側装置１０１に提供した時刻を記録し、動作がＳ１６０８から進んだ場合であれば、送信者Ａの最新の秘密鍵Ｓ２を生成した時刻を記録することになる。
【０１２２】
次にＳ１６１０において共通鍵暗号化部１１２により共通鍵Ｃ２を用いて秘密鍵Ｓ２を暗号化し、それを送信者Ａ側装置１０１に送信する。
【０１２３】
送信者Ａ側装置１０１は、Ｓ１６１１において共通鍵復号化部１０５により共通鍵Ｃ２を用いて登録局ＲＡ側装置１０８から受信した秘密鍵Ｓ２を復号化する。次にＳ１６１２において署名生成部１０６により任意の関数を用いて電子文書Ｅのハッシュ値を算出し、それを秘密鍵Ｓ１を用いて暗号化してデジタル署名Ｇ１を生成するとともに、関数情報Ｆも秘密鍵Ｓ１を用いて暗号化する。そして、ＩＤ番号と暗号化されたデジタル署名Ｇ１と関数情報Ｆを電子文書Ｅに付加して受信者Ｂ側装置１２０に送信する。
【０１２４】
以上説明したように、本発明の第５実施例によれば、１回の本人確認で生成した鍵を、所定時間内に限り、複数の署名に利用できるため、一定水準以上のシステムのセキュリティを確保した状態で鍵を提供する速度を速めることができ、システムの利便性を向上させることができる。
【０１２５】
＜第６実施例＞
第６実施例は、第５実施例では登録局ＲＡ側装置１０８が発行済み秘密鍵Ｓ２の流用する時刻を管理するのに対し、送信者Ａ側装置１０１が管理するように構成にしたものである。
【０１２６】
図１７は第６実施例の構成図である。第６実施例は、第５実施例に対し、送信者Ａ側装置１０８に秘密鍵記憶部１７０１を加えたものである。
【０１２７】
秘密鍵記憶部１７０１は第４実施例で説明した秘密鍵記憶部１２０１と同様の部位である。すなわち、秘密鍵記憶部１７０１は、登録局ＲＡ側装置１０８から送信者Ａ側装置１０１に提供された秘密鍵Ｓ２を記録する部位である。送信者Ａ側装置１０１は、秘密鍵記憶部１７０１に記録された秘密鍵Ｓ２を流用してデジタル署名Ｇ１を生成することになる。なお、送信者Ａ側装置１０１は、署名生成部１０６により秘密鍵Ｓ２を秘密鍵記憶部１２０１に記録した時刻を監視している。そして、記録した時刻から所定時間経過している場合に、送信者Ａ側装置１０１は、送信者Ａの生体特徴情報Ｄを取得してそれを登録局ＲＡ側装置１０８に送信し、登録局ＲＡ側装置１０８に送信者Ａの新たな秘密鍵Ｓ２を生成させる。
【０１２８】
第６実施例の動作は、署名生成処理時および署名確認処理時に第５実施例と相違する。そこで、以下に、これらの動作について説明する。
【０１２９】
まず、署名生成処理時の動作について、図１８を用いて説明する。なお、図１８は署名生成処理のフローチャートである。
【０１３０】
送信者Ａ側装置１０１は、初めにＳ１８０１において秘密鍵記憶部１７０１に記録されている送信者Ａの発行済みの秘密鍵Ｓ２を流用するのかを判断する。流用するのであれば、Ｓ１８０２において秘密鍵記憶部１７０１から送信者Ａの秘密鍵Ｓ２を読み出し、動作をＳ１８１４に進める。流用しないのであれば、動作をＳ１８０３に進める。
【０１３１】
Ｓ１８０３において生体特徴取得部１０２により送信者Ａの生体特徴情報Ｄを取得する。次にＳ１８０４において共通鍵生成部１０３により共通鍵Ｃ２を生成する。なお、共通鍵Ｃ２は送信者Ａの利用者（送信者）登録処理時に用いた共通鍵Ｃ１と異なっても良いものであり、乱数などを用いることができる。次にＳ１８０５において公開鍵暗号化部１０４により登録局ＲＡの公開鍵暗号P０を用いて生体特徴情報Ｄと共通鍵Ｃ２を暗号化し、それを登録局ＲＡ側装置１０８に送信する。
【０１３２】
登録局ＲＡ側装置１０８は、Ｓ１８０６において秘密鍵復号化部１０９により自身の秘密鍵Ｓ０を用いて送信者Ａ側装置１０１から送信された生体特徴情報Ｄと共通鍵Ｃ２を複号化する。次にＳ１８０７において本人確認部１１０により送信者Ａ側装置１０１から送信された生体特徴情報Ｄと個人情報データベース１１４に登録されている生体特徴情報Ｄとを照合して本人確認を行う。
【０１３３】
本人と確認された場合に、Ｓ１８０８において秘密鍵・公開鍵生成部１１１により送信者Ａの秘密鍵Ｓ２と公開鍵Ｐ２を新たに生成する。これらの鍵は送信者Ａの登録時や前回の署名生成処理時に生成した秘密鍵や公開鍵と異なっていることが望ましい。次にＳ１８０９において補正情報生成部５０１により補正情報Ｒ１を生成し、個人情報データベース１１４に登録する。なお、補正情報Ｒ１は新たに生成した送信者Ａの公開鍵Ｐ２と個人情報データベースに登録されている送信者Ａの公開鍵Ｐ１を用いて以下の式７により算出したものである。また個人情報データベース１１４に登録する補正情報Ｒ１は常に最新のものだけとする。
【０１３４】
【数７】

【０１３５】
次にＳ１８１０において時間記録部１３０１に送信者Ａの最新の秘密鍵Ｓ２を生成した時刻を記録させる。
【０１３６】
次にＳ１８１１において共通鍵暗号化部１１２により共通鍵Ｃ２を用いて秘密鍵Ｓ２を暗号化し、それを送信者Ａ側装置１０１に送信する。
【０１３７】
送信者Ａ側装置１０１は、Ｓ１８１２において共通鍵復号化部１０５により共通鍵Ｃ２を用いて登録局ＲＡ側装置１０８から受信した秘密鍵Ｓ２を復号化する。Ｓ１８１３において秘密鍵Ｓ２を秘密鍵記憶部１２０１に記録する。なお、このときの時刻も秘密鍵記憶部１２０１に記録する。次にＳ１８１４において署名生成部１０６により任意の関数を用いて電子文書Ｅのハッシュ値を算出し、それを秘密鍵Ｓ１を用いて暗号化してデジタル署名Ｇ１を生成するとともに、関数情報Ｆも秘密鍵Ｓ１を用いて暗号化する。そして、ＩＤ番号と暗号化されたデジタル署名Ｇ１と関数情報Ｆを電子文書Ｅに付加して受信者Ｂ側装置１２０に送信する。
【０１３８】
なお、以降の署名生成処理動作は、秘密鍵記憶部１７０１に記憶された秘密鍵Ｓ２を流用することで、Ｓ１８０３からＳ１８１３までの動作を省くことができる。この場合、秘密鍵Ｓ２を流用するのか、否か（すなわち、登録局ＲＡ側装置１０８に新規に生成させるのか）は、送信者Ａ側装置１０１が秘密鍵Ｓ２の提供を受けてからの経過時間に基づいて判断することになる。
【０１３９】
次に署名確認処理時の動作について、図１９を用いて説明する。図１９は署名確認処理のフローチャートである。なお、本実施例では、登録局ＲＡ側装置１０８は受信者Ｂ側装置１２０からの送信者Ａの補正情報Ｒ１の提供を要求した時刻を監視している。そして、送信者Ａの秘密鍵Ｓ２を送信者Ａ側装置１０１に提供した時刻から所定時間経過している場合に、登録局ＲＡ側装置１０８は、受信者Ｂ側装置１２０への送信者Ａの補正情報Ｒ１の提供を中止する。これにより登録局ＲＡ側装置１０８は、一定水準以上のシステムのセキュリティを確保している。
【０１４０】
受信者Ｂ側装置１２０は、送信者Ａ側装置１０１から電子文書Ｅとデジタル署名が送信された場合に、Ｓ１９０１において公開鍵要求部１２１により認証局ＣＡに対して電子文書Ｅに付加されたＩＤ番号を送信して送信者Ａの公開鍵Ｐ１の提供を要求する。
【０１４１】
認証局ＣＡ側装置１１５は、Ｓ１９０２において受信したＩＤ番号により公開鍵データベース１１９に登録されている送信者Ａを特定し、送信者Ａの公開鍵P１を受信者Ｂ側装置１２０に送信する。
【０１４２】
受信者Ｂ側装置１２０は、Ｓ１９０３において認証局ＣＡ側装置１１５から送信者Ａの公開鍵Ｐ１を取得する。次にＳ１９０４において補正情報要求部５０３により登録局ＲＡ側装置１０８に対して電子文書Ｅに付加されたＩＤ番号を送信して送信者Ａの補正情報Ｒ１の提供を要求する。
【０１４３】
登録局ＲＡ側装置１０８は、Ｓ１９０５において、送信者Ａの秘密鍵Ｓ２を送信者Ａ側装置１０１に提供した時刻から所定時間内であるのかをチェックする。所定時間内であれば、動作をＳ１９０６に進め、所定時間経過していれば、送信者Ａの補正情報Ｒ１を提供できない旨を受信者Ｂ側装置１２０に送信する。なお、所定時間経過している場合には、秘密鍵Ｓ２の再利用を防ぐため、補正情報提供部５０２は個人情報データベース１１４から補正情報Ｒ１を抹消する。
【０１４４】
Ｓ１９０６において鍵補正情報提供部５０２により個人情報データベース１１４に登録されている送信者Ａの最新の補正情報Ｒ１を受信者Ｂ側装置１２０に送信する。
【０１４５】
受信者Ｂ側装置１２０は、Ｓ１９０７において登録局ＲＡ側装置１０８から補正情報Ｒ１を取得する。次にＳ１９０８において公開鍵補正部５０４により公開鍵Ｐ１を補正する。なお、補正により得られる公開鍵Ｐ２は認証局ＣＡから取得した送信者Ａの公開鍵Ｐ１と登録局ＲＡから取得した送信者Ａの最新の補正情報Ｒ１を用いて以下の式８により算出したものである。
【０１４６】
【数８】

【０１４７】
次にＳ１９０９において署名確認部１２２により算出した送信者Ａの公開鍵Ｐ２を用いて送信者Ａから受信した電子文書Ｅに付加されたデジタル署名Ｇ１を復号化して送信者Ａが算出したハッシュ値を取得するとともに、関数情報Ｆも送信者Ａの公開鍵Ｐ２を用いて復号化してそれにより特定された関数を用いて受信した電子文書Ｅのハッシュ値を算出し、２つのハッシュ値を比較する。これにより送信者がＡ本人であるであることを確認する。
【０１４８】
以上説明したように、本発明の第６実施例によれば、送信者Ａ側装置１０１は、以前取得した鍵をデジタル署名Ｇ１の生成に流用する。そのため、送信者Ａ側装置１０１は、登録局ＲＡ側装置１０８と通信しなくてもよいので、第５実施例よりも早く電子的な情報を受信者Ｂ側装置１２０に提供することができる。
【０１４９】
本発明は上記の実施例に限定されることなく、本発明の要旨を逸脱しない範囲で種々の応用及び変形が考えられる。
【０１５０】
例えば、本発明は、様々な電子情報の発行者を保証する仕組みとして利用することができる。例えば、電子商取引における注文書の発行者や、戸籍謄本や住民票などの公文書の発行者、その他ネットワークによる電子申請における電子情報の発行者を保証する仕組みに利用できる。
【０１５１】
また、登録局ＲＡ側装置は、個人情報データベース１１４に登録されている送信者Ａの生体特徴情報Ｄを用いて送信者Ａの秘密鍵Ｓ１や公開鍵Ｐ１、補正情報Ｒ１を生成することが可能である。図８に示すように、個人情報データベース１１４には、送信者Ａの生体特徴情報Ｄが登録されている。
【０１５２】
例えば氏名「山田太郎」の場合、生体特徴情報Ｄは「１０１１１００１００１０」である。生体特徴情報Ｄは、本実施例のようにアイリスから取得した場合、数十〜数百バイトの大きさである。この規模の大きさの情報であれば、様々な値を抽出することができ、例えば値「１」の個数（図８の例では、氏名「山田太郎」の場合、６個）や値「０」の個数（同、６個）、値「１」が連続する箇所の個数（同、１個）、値「０」が連続する箇所の個数（同、２個）などを抽出することができる。そのため、登録局ＲＡ側装置は、任意のアルゴリズムに基づいて生体特徴情報Ｄを用いて送信者Ａの秘密鍵Ｓ１や公開鍵Ｐ１、補正情報Ｒ１を生成することが可能となる。
【０１５３】
また、システムが生体特徴情報Ｄによる本人確認を行うことにより利用が可能になるように構成されている場合、本人確認を行う認証装置が登録局ＲＡの役割を担うことが可能である。このように構成されたシステムは、システムの利用が可能になった時点で生体特徴情報Ｄが取得されているので、この時点で生体特徴情報Ｄを登録局ＲＡに伝送しておけば署名生成処理時に生体特徴情報Ｄを取得する工程を省略することができる。
【０１５４】
また、上記の実施例において、送信者Ａ側装置１０１は、登録局ＲＡ側装置１０８から秘密鍵Ｓ１，Ｓ２を受信する際に共通鍵Ｃ１，Ｃ２を用いているが、共通鍵Ｃ１，Ｃ２の代わりに公開鍵Ｐ１，Ｐ２やその他を用いるように構成することも可能である。例えば、送信者Ａが別途新たな秘密鍵Ｓ’および公開鍵Ｐ’を生成して公開鍵Ｐ’を登録局ＲＡに伝送するとともに、登録局ＲＡはその公開鍵Ｐ’を用いて秘密鍵Ｓ’を暗号化して送信者Ａに送信する。そして、送信者Ａは登録局ＲＡから送信された秘密鍵Ｓ’を復号化し、復号化した秘密鍵Ｓ’を用いてデジタル署名を生成するように構成することも可能である。
【０１５５】
また、認証局ＣＡ側装置１１５や受信者Ｂ側装置１２０は送信者を特定する情報としてＩＤ番号を用いているが、生体特徴情報やその他の情報を用いることも可能である。
【０１５６】
また、上記の実施例では、登録局ＲＡにおける本人確認を生体特徴情報Ｄを用いて行っているが、この代わりに従来より用いられているパスワードやＩＣカードを利用するようにすることも可能である。
【０１５７】
【発明の効果】
以上説明した本発明には、次の効果がある。
【０１５８】
すなわち、送信者Ａは秘密鍵や公開鍵を発行する際の手間を省くことができる上、自身の秘密鍵を厳重に管理する煩わしさをなくすことができる。そのため、デジタル署名を利用する通信の利便性を向上させることができる。
【図面の簡単な説明】
【図１】第１実施例の構成図である。
【図２】利用者登録処理のフローチャートである。
【図３】署名生成処理のフローチャートである。
【図４】署名確認処理のフローチャートである。
【図５】第２実施例の構成図である。
【図６】署名生成処理のフローチャートである。
【図７】署名確認処理のフローチャートである。
【図８】情報の流れを示す図である。
【図９】情報の流れを示す図である。
【図１０】第３実施例の構成図である。
【図１１】署名生成処理のフローチャートである。
【図１２】第４実施例の構成図である。
【図１３】署名生成処理のフローチャートである。
【図１４】署名確認処理のフローチャートである。
【図１５】第５実施例の構成図である。
【図１６】署名生成処理のフローチャートである。
【図１７】第６実施例の構成図である。
【図１８】署名生成処理のフローチャートである。
【図１９】署名確認処理のフローチャートである。
【符号の説明】
１０１ 送信者Ａ側装置
１０２ 生体特徴取得部
１０３ 共通鍵生成部
１０４ 公開鍵暗号化部
１０５ 共通鍵復号化部
１０６ 署名生成部
１０７ 通信部
１０８ 登録局ＲＡ側装置
１０９ 秘密鍵復号化部
１１０ 本人確認部
１１１ 秘密鍵・公開鍵生成部
１１２ 共通鍵暗号化部
１１３ 通信部
１１４ 個人情報データベース
１１５ 認証局ＣＡ側装置
１１６ 公開鍵登録部
１１７ 公開鍵提供部
１１８ 通信部
１１９ 公開鍵データベース
１２０ 受信者Ｂ側装置
１２１ 公開鍵要求部
１２２ 署名確認部
１２３ 通信部[0001]
BACKGROUND OF THE INVENTION
The present invention, for example, a person who acquired electronic information such as a document, an image, and a sound (hereinafter referred to as an acquirer) provided the information from a digital signature added to the electronic information (hereinafter referred to as an acquirer). It is related with the provider confirmation system which confirms (it describes with a provider).
[0002]
[Prior art]
For example, conventionally, electronic documents such as electronic documents (information obtained by signaling pictures, medical records, resident's cards, family register abstracts, etc.), moving images, still images, information used in electronic commerce, etc. There are communication devices that transmit remote information to remote locations. Some of such communication devices are configured to be able to confirm from whom the electronic information acquirer has acquired the electronic information. Hereinafter, an example thereof will be described based on a system for communicating electronic documents. In the following description, the provider is referred to as a sender, and the acquirer is referred to as a receiver.
[0003]
The system includes a sender-side device that transmits data, a certification authority-side device that authenticates that the sender is the user, and a receiver-side device that receives data. Here, the description will be made assuming that the certificate authority side apparatus provides the receiver side apparatus with the sender's public key provided to authenticate that the sender is the principal.
[0004]
First, the sender generates the keys (secret key and public key) necessary for encrypting / decrypting data in advance, stores the private key by itself, and sends the public key to the certificate authority. Let me register there.
[0005]
Then, when the electronic document is transmitted to the receiver, the sender calculates a hash value (summary information) of the electronic document using an arbitrary function, and encrypts the hash value (summary information) using the private key to generate a digital signature. . Then, information specifying a digital signature and a function used for calculating the hash value (hereinafter referred to as function information) is added to the electronic document and transmitted to the recipient.
[0006]
Recipients who have received an electronic document with a digital signature access the certificate authority, obtain the sender's public key from it, and decrypt the digital signature attached to the electronic document using the sender's public key. The hash value calculated by the sender is acquired, and the hash value of the received electronic document is calculated using the function specified by the function information. Then, the two hash values obtained by these are compared to confirm that the sender is the principal.
[0007]
[Problems to be solved by the invention]
In the above system, if the sender's private key is leaked to a third party, the third party can impersonate the sender and send an electronic document with the sender's fake digital signature. Become. Therefore, the sender has to store the secret key strictly so that the secret key is not leaked to a third party. In addition, the sender has to generate a private key and a public key by himself, but the work is troublesome. Therefore, due to these factors, the above system has been difficult to spread.
[0008]
The present invention solves the problem that the sender must store the secret key strictly and the problem that the sender must generate the key, thereby providing a system with improved safety and convenience. For the purpose.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a first invention provides a provider confirmation system in which a person who has acquired electronic information confirms a provider of electronic information from a digital signature added to the electronic information. A provider's private key and public key by acquiring information unique to the provider, and registering the generated provider's private key, and the provider's secret generated by the registration station's device A provider-side device that generates an encrypted digital signature using a key, adds the generated digital signature to electronic information, and registers the provider's public key, and the provider's public key is electronically registered. The certificate authority side device to be provided to the acquirer of the local information and the provider provided by acquiring the public key of the provider from the certificate authority side device based on the information specifying the provider added to the electronic information Information using the public key Have the acquisition side apparatus for decoding a digital signature appended Then, when the registration authority side device generates the provider's new secret key and public key, the registration authority side device transmits the provider's new secret key to the provider side device, and the provider's new public key and provider The correction information obtained by calculating the difference from the issued public key is registered in itself, and the acquirer side device acquires the issued public key of the provider from the certificate authority side device, and the registration By acquiring correction information from the station side device, the provider's issued public key is corrected and the provider's new public key is acquired. It is characterized by that.
[0010]
In addition to the first invention, the second invention The registration station side device can transmit correction information to the acquirer side device only within a predetermined number of times or within a predetermined time. It is characterized by that.
[0017]
The second 3 According to the present invention, in a provider confirmation method in which a person who has acquired electronic information confirms a provider of electronic information from a digital signature added to the electronic information, the provider side device discloses the secret key and the public key. A step of transmitting provider-specific information to a registration authority side device that generates a key; a step of generating a private key and a public key of the provider by the registration authority side device; and a provider generated by the registration authority side device And the provider side device acquires the provider's private key from the registration authority side device, and generates an encrypted digital signature using the acquired provider's private key. In addition, the step of adding the encrypted digital signature to the electronic information, and the acquirer side device to the certification authority side device in which the public key of the provider generated by the registration authority side device is registered Requesting the provider's public key and the authentication A step in which the side device transmits the provider's public key to the acquirer side device; and a step in which the acquirer side device decrypts the digital signature added to the electronic information using the provider's public key; Have Then, when the registration authority side device generates the provider's new secret key and public key, the registration authority side device transmits the provider's new secret key to the provider side device, and the provider's new public key and provider The correction information obtained by calculating the difference with the issued public key is registered in itself, and the acquirer side device acquires the public key issued by the provider from the certification authority side device, and the registration authority side By acquiring correction information from the device, the provider's issued public key is corrected and the provider's new public key is acquired. It is characterized by that.
[0018]
In addition 4 The invention of the 3 In addition to the invention of Correction information can be transmitted to the acquirer side device only within a predetermined number of times or within a predetermined time. It is characterized by that.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the sender's biometric feature information (for example, data obtained by coding a pattern such as an iris or fingerprint or a waveform of a voiceprint based on a predetermined algorithm) and the sender's private key are associated with each sender. A registration authority RA for registration is provided. In the present invention, for example, when communicating an electronic document, each device operates as follows.
[0025]
In the following description, since electronic information is transmitted and received via a network, an information provider is referred to as a sender and an information acquirer is referred to as a receiver. However, electronic information may not be transmitted / received via a network. For example, the provider can provide electronic information to the acquirer using a storage medium such as a floppy disk, CD-ROM, DVD, or IC chip. In this case, the provider side device and the acquirer side device need not be connected via a network. The present invention includes such a configuration.
[0026]
First, the sender obtains his / her own biometric feature information in advance, transmits it to the registration station RA, and registers it there. At this time, the registration authority RA generates the sender's secret key and public key, registers the secret key in association with the sender's biometric feature information, and transmits the public key to the sender. The sender transmits the public key received from the registration authority RA to the certification authority CA and registers it there.
[0027]
Then, when the sender transmits the electronic document to the receiver, the sender again acquires biometric feature information and transmits it to the registration station RA. Then, the registration station RA compares the received sender's biometric feature information with the sender's biometric feature information registered in itself, and confirms that the sender is the sender. When the registration authority RA confirms that the sender is the principal, the registration authority RA transmits the secret key registered in association with the biometric feature information of the sender to the sender.
[0028]
Thereafter, the sender calculates a hash value of the electronic document using an arbitrary function, encrypts the hash value using a secret key, generates a digital signature, and encrypts function information using the secret key. . Then, the encrypted digital signature and function information are added to the electronic document and transmitted to the recipient.
[0029]
The receiver who has received the electronic document accesses the certificate authority CA, obtains the sender's public key therefrom, decrypts the digital signature added to the electronic document using the sender's public key, and sends the sender In addition to acquiring the calculated hash value, the function information is also decrypted using the sender's public key, and the hash value of the received electronic document is calculated using the function specified thereby. Then, the two hash values obtained by these are compared to confirm that the sender is the principal.
[0030]
Embodiments of the present invention will be described below with reference to the drawings. Each figure is shown only schematically to the extent that the present invention can be understood. Moreover, in each figure, about the common element, the same code | symbol is attached | subjected and description is abbreviate | omitted.
[0031]
<First embodiment>
FIG. 1 is a block diagram of the first embodiment.
[0032]
As shown in the figure, the sender A side apparatus 101 includes a biometric feature acquisition unit 102, a common key generation unit 103, a public key encryption unit 104, a common key decryption unit 105, a signature generation unit 106, and a communication unit 107. Yes. The registration authority RA side device 108 includes a secret key decryption unit 109, an identity verification unit 110, a secret key / public key generation unit 111, a common key encryption unit 112, a communication unit 113, and a personal information database 114. The certificate authority CA side device 115 includes a public key registration unit 116, a public key provision unit 117, a communication unit 118, and a public key database 119. The receiver B side device 120 includes a public key request unit 121, a signature confirmation unit 122, and a communication unit 123. Note that the registration authority RA and the certification authority CA can be integrated. However, the distribution as in the present embodiment can limit the person who knows the mechanism for generating the secret key S1, thereby making it easier to prevent leakage of secrets and improving security. Therefore, this is preferable.
[0033]
Hereinafter, first, the configuration of the sender A side apparatus 101 will be described. In this system, in advance, the device 108 of the registration authority RA generates its own private key S0 and public key P0 by the private key / public key generation unit 111, stores the private key S0 by itself, and also uses the public key. It is assumed that P0 is transmitted to the outside (sender A, certificate authority CA, receiver B, etc.). Thus, the sender A and others can communicate with the registration authority RA by encrypting / decrypting data using the public key P0.
[0034]
The biometric feature acquisition unit 102 includes, for example, a camera (or sensor) and an image processing device, and is a part that acquires the biometric feature information D of the sender A. In this embodiment, it is assumed that the biometric feature acquisition unit 102 acquires biometric feature information D by photographing the eyes of the sender and coding the iris pattern in the eyes.
[0035]
The common key generation unit 103 is a part that generates a common key C1 used for encrypted communication between the sender A and the registration authority RA. The public key encryption unit 104 is a part that encrypts the biometric feature information D and the common key C1 of the sender A using the public key P0 of the registration station RA generated by the registration station RA. The biometric feature information D and the common key C1 of the sender A encrypted by the public key encryption unit 104 are transmitted to the registration authority RA side device 108. The common key decryption unit 105 is a part for decrypting the secret key S1 (encrypted) of the sender A transmitted from the registration authority RA using the common key C1. The decrypted secret key S1 is used to generate the digital signature G1. The signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function, encrypts it using the secret key S1, generates a digital signature G1, and also uses the secret key S1 for the function information F. The encrypted digital signature G1 and the function information F are added to the electronic document E. The communication unit 107 is a part that performs communication with the outside. The electronic document E is transmitted to the receiver B side device 120 from here.
[0036]
Next, the configuration of the registration station RA side apparatus 108 will be described. The personal information database 114 of the registration authority RA stores the personal information of the sender A by the sender A (for example, a serial number (hereinafter referred to as an ID number) assigned to the sender A by the device 108, a name, It is assumed that biometric feature information D and the like are registered in advance. In the present embodiment, description will be made assuming that the certificate authority CA side device 115 and the receiver B side device 120 use an ID number as information for identifying the sender. The private key decryption unit 109 decrypts the biometric feature information D and the common key C1 (both encrypted by the public key encryption unit 104) received from the sender A side apparatus 101 using the private key S0. It is a part. The identity verification unit 110 is a part that collates the decrypted biometric feature information D of the sender A with the biometric feature information D of the sender registered in the personal information database 114. When the two pieces of biometric feature information D match within the allowable range, the identity verification unit 110 outputs a signal for authenticating that the sender A is the identity (hereinafter referred to as an authentication signal).
[0037]
The secret key / public key generation unit 111 is a part that generates the secret key S1 and the public key P1 of the sender A. The common key encryption unit 112 is a part that encrypts the private key S1 and the public key P1 of the sender A. Note that, as will be described later, the secret key S1 is encrypted / decrypted, for example, using the common key C2 during signature generation processing. As will be described later, the public key P1 is encrypted / decrypted using the common key C1 at the time of user (sender) registration processing, for example. The communication unit 113 is a part that performs communication with the outside. The personal information database 114 is a part for registering the personal information of the sender A (ID number, name, biometric feature information D, secret key S1, etc.) for each sender.
[0038]
Next, the configuration of the certificate authority CA side device 115 will be described. The public key registration unit 116 is a part that registers the public key P1 of the sender A in the public key database 119. The public key providing unit 117 is a part that transmits the public key P1 of the sender A to the receiver B side device 120 based on the provision request from the receiver B. The communication unit 118 is a part that communicates with the outside. The public key database 119 is a part for registering the public key P1 of the sender A.
[0039]
Next, the configuration of the receiver B side device 120 will be described. The public key request unit 121 is a part that requests the certification authority CA to provide the public key P1 of the sender A. The signature verification unit 122 decrypts the digital signature G1 added to the electronic document E received from the sender A by using the public key P1 of the sender A received from the certificate authority RA, and the hash value calculated by the sender A And the function information F is also decrypted using the public key P1 of the sender A, the hash value of the received electronic document E is calculated using the function specified thereby, and the two hash values are compared. It is a part. When the two hash values match, the signature verification unit 122 outputs a signal for authenticating that the sender A is the person (hereinafter referred to as an authentication signal). The communication unit 123 is a part that performs communication with the outside.
[0040]
Below, the flow of information transmitted and received between systems will be described. FIG. 8 is a diagram showing a flow of information transmitted and received between the sender A side apparatus 101, the registration authority RA side apparatus 108, and the certification authority CA side 115, and FIG. It is a figure which shows the flow of the information transmitted / received between the person B side apparatus 1120 and 115 by the certificate authority CA side.
[0041]
As shown in FIG. 8, the name, common key C <b> 1, and biometric feature information D are transmitted from the sender A side apparatus 101 to the registration station RA side apparatus 108, and from the registration station RA side apparatus 108 to the sender A side apparatus 101. The ID number, the public key P0 of the registration authority RA, the secret key S1 of the sender A, and the public key P1 of the sender A are transmitted. As will be described later, the registration authority RA transmits the public key P0 of the registration authority RA before the user (sender) registration process or the signature generation process, and also transmits the private key S1 of the sender A. Sent during signature generation processing (not transmitted during user (sender) registration processing), and transmits the public key P1 of sender A during user (sender) registration processing (not transmitted during signature generation processing). . The ID number and the public key P1 are transmitted from the sender A side device 101 to the certificate authority CA side device 115.
[0042]
On the other hand, as shown in FIG. 9, the ID number, the electronic document E, and the digital signature G1 are transmitted from the sender A side apparatus 101 to the receiver B side apparatus 120. Further, the ID number is transmitted from the receiver B side device 120 to the certificate authority CA side device 115, and the public key P1 is transmitted from the certificate authority CA side device 115 to the receiver B side device 120.
[0043]
2 to 4 are a flowchart of a user (sender) registration process, a flowchart of a signature generation process, and a flowchart of a signature confirmation process, respectively.
[0044]
Hereinafter, the operation of the first embodiment will be described in three parts: at the time of user (sender) registration processing, at the time of signature generation processing, and at the time of signature confirmation processing. In the following operation, a method for generating a secret key and a public key, encryption and decryption, and a method for generating and confirming a digital signature will be described as using a conventional method.
[0045]
First, the operation at the time of user (sender) registration processing will be described with reference to FIG. In this system, as described above, the device 108 of the registration authority RA generates its own private key S0 and public key P0 by the private key / public key generation unit 111 in advance and registers the private key S0 with itself. At the same time, the public key P0 is transmitted to the outside (sender A, certificate authority CA, receiver B, etc.).
[0046]
The sender A side apparatus 101 first acquires the biometric feature information D of the sender A by the biometric feature acquisition unit 102 in step (hereinafter referred to as S) 201. In step S202, the common key generation unit 103 generates a common key C1. Note that a random number or the like can be used for C1. Next, in S203, the public key encryption unit 104 encrypts the biometric feature information D, the common key C1, and the name using the public key P0 of the registration authority RA, and transmits it to the registration authority RA.
[0047]
The registration station RA side apparatus 108 decrypts the biometric feature information D, the common key C1, and the name received from the sender A side apparatus 101 by using the secret key S0 of the registration station RA by the secret key decryption unit 109 in S204. . Next, in S205, the private key / public key generation unit 111 generates the private key S1 and the public key P1 of the sender A. In step S206, the biometric feature information D and the secret key S1 of the sender A are registered in the personal information database 114. In S207, the common key encryption unit 112 encrypts the public key P1 using the common key C1, and transmits it to the sender A.
[0048]
The sender A apparatus 101 decrypts the public key P1 received from the registration authority RA by the common key decryption unit 105 in S208, and transmits the public key P1 and the ID number to the certification authority CA side apparatus 115 in S209 for authentication. Instructs the station CA to register.
[0049]
In S210, the certification authority CA side apparatus 115 registers the public key P1 and ID number of the sender A in the public key database 119 by using the public key registration unit 116.
[0050]
Next, the operation during the signature generation process will be described with reference to FIG.
[0051]
The sender A device 101 first acquires the biometric feature information D of the sender A by the biometric feature acquisition unit 102 in S301. In step S302, the common key generation unit 103 generates a common key C2. The common key C2 may be different from the common key C1 used at the time of user (sender) registration processing of the sender A, and a random number or the like can be used. In step S303, the public key encryption unit 104 encrypts the biometric feature information D and the common key C2 using the public key encryption P0 of the registration authority RA, and transmits the encrypted information to the registration authority RA side apparatus 108.
[0052]
In S304, the registration authority RA side apparatus 108 decrypts the biometric feature information D and the common key C2 received from the registration authority RA apparatus 108 by using the private key S0 by the secret key decryption unit 109. In step S <b> 305, the identity verification unit 110 compares the biometric feature information D received from the sender A device 101 with the biometric feature information D registered in the personal information database 114 to perform identity verification. When the identity is confirmed, the secret key S1 of the sender A registered in the personal information database 114 is encrypted using the common key C2 by the common key encryption unit 112 in S306, and this is transmitted to the sender A side device. 101.
[0053]
In S307, the sender A apparatus 101 uses the common key decryption unit 105 to decrypt the secret key S1 received from the registration authority RA side apparatus 108 using the common key C2. Next, in S308, the signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function, encrypts the hash value using the secret key S1, and generates the digital signature G1, and the function information F also includes the secret key. Encrypt using S1. Then, the ID number, the encrypted digital signature G1 and the function information F are added to the electronic document E and transmitted to the receiver B side device 120.
[0054]
Next, the operation at the time of signature confirmation processing will be described with reference to FIG. When the electronic document E and the digital signature are transmitted from the sender A side device 101, the receiver B side device 120 transmits the ID added to the electronic document E to the certification authority CA by the public key request unit 121 in S401. The number is transmitted to request the provision of the public key P1 of the sender A.
[0055]
The certificate authority CA side apparatus 115 identifies the sender a registered in the public key database 119 by the ID number received in S402, and transmits the public key P1 of the sender A to the receiver B side apparatus 120.
[0056]
The receiver B side device 120 acquires the public key P1 of the sender A from the certificate authority CA side device 115 in S403. Next, in step S404, the digital signature G1 added to the electronic document E received from the sender A is decrypted by the signature confirmation unit 122 using the public key P1 of the sender A received from the certificate authority RA, and the sender A calculates And the function information F is also decrypted using the public key P1 of the sender A, the hash value of the received electronic document E is calculated using the function specified thereby, and two hash values are obtained. Compare As a result, the sender is A Is Make sure.
[0057]
As described above, according to the first embodiment, when the sender A transmits its biometric feature information D to the registration station RA, the registration station RA obtains the private key S1 and the public key P1 of the sender A. When the digital signature is generated, the sender A transmits the biometric feature information D to the registration station RA, so that the registration station RA transmits the private key S1 of the sender A to the sender A. Therefore, the sender A can save the trouble of issuing the secret key S1 and the public key P1, and can eliminate the trouble of strictly managing the secret key S1. Moreover, since the information (function information) for specifying the function used for calculating the hash value is also encrypted / encoded with the private key S1 and the public key P1 of the sender A, the security for the function information can be improved. it can. Therefore, the convenience of a system that uses a digital signature can be improved.
[0058]
<Second embodiment>
In the second embodiment, the registration authority RA generates a new secret key and transmits it to the sender A at any time in order to avoid unauthorized use of the secret key S1. The timing for newly generating the secret key is arbitrary, but is performed, for example, every time the sender A issues a digital signature (that is, every time the electronic document E with the digital signature added is transmitted to the receiver B). May be. The receiver B acquires information R1 for correcting the public key P1 from the registration authority RA and corrects the public key P1, thereby acquiring a new public key P2 necessary for decrypting the digital signature.
[0059]
FIG. 5 is a block diagram of the second embodiment. The second embodiment adds a correction information generating unit 501 and a correction information providing unit 502 to the registration station RA side device 108 and also adds a correction information requesting unit 503 and a public key to the receiver B side device 120, compared to the first example. A correction unit 504 is added.
[0060]
The correction information generation unit 501 is a part that generates correction information R1 for calculating the new public key P2 of the sender A from the old public key P1 of the sender A. The correction information providing unit 502 is a part for transmitting the correction information R1 to the sender A. The correction information request unit 503 is a part that requests the registration station RA to provide the correction information R1 of the sender A. The public key correction unit 504 is a part that calculates the new public key P2 of the sender A from the old public key P1 of the sender A using the correction information R1.
[0061]
The operation of the second embodiment is different from that of the first embodiment during signature generation processing and signature confirmation processing. Therefore, these operations will be described below.
[0062]
First, the operation during the signature generation process will be described with reference to FIG. FIG. 6 is a flowchart of the signature generation process.
[0063]
First, in step S <b> 601, the sender A side apparatus 101 acquires the biometric feature information D of the sender A by the biometric feature acquisition unit 102. In step S <b> 602, the common key generation unit 103 generates a common key C <b> 2. The common key C2 may be different from the common key C1 used at the time of user (sender) registration processing of the sender A, and a random number or the like can be used. In step S <b> 603, the public key encryption unit 104 encrypts the biometric feature information D and the common key C <b> 2 using the public key encryption P <b> 0 of the registration authority RA, and transmits it to the registration authority RA side apparatus 108.
[0064]
The registration authority RA side device 108 uses the private key S0 by the private key decryption unit 109 in S604. Sender A side device 101 The biometric feature information D and the common key C2 transmitted from are decrypted. In step S <b> 605, the identity verification unit 110 compares the biometric feature information D transmitted from the sender A-side device 101 with the biometric feature information D registered in the personal information database 114 to perform identity verification. When the user is confirmed, the private key / public key generation unit 111 newly generates the private key S2 and the public key P2 of the sender A in S606. These keys are preferably different from the secret key or public key generated at the time of registration of the sender A or the previous signature generation process. In step S <b> 607, the correction information generation unit 501 generates correction information R <b> 1 and registers it in the personal information database 114. The correction information R1 is calculated by the following equation 1 using the newly generated public key P2 of the sender A and the public key P1 of the sender A registered in the personal information database. The correction information R1 registered in the personal information database 114 is always only the latest information.
[0065]
[Expression 1]

[0066]
In step S <b> 608, the secret key S <b> 2 is encrypted by the common key encryption unit 112 using the common key C <b> 2 and transmitted to the sender A side apparatus 101.
[0067]
In S609, the sender A side apparatus 101 uses the common key decryption unit 105 to decrypt the secret key S2 received from the registration authority RA side apparatus 108 using the common key C2. In step S610, the signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function, encrypts the hash value using the secret key S1, and generates the digital signature G1. The function information F also includes the secret key. Encrypt using S1. Then, the ID number, the encrypted digital signature G1 and the function information F are added to the electronic document E and transmitted to the receiver B side device 120.
[0068]
Next, the operation at the time of signature confirmation processing will be described with reference to FIG. FIG. 7 is a flowchart of the signature confirmation process.
[0069]
When the electronic document E and the digital signature are transmitted from the sender A side apparatus 101, the receiver B side apparatus 120 transmits the ID added to the electronic document E to the certification authority CA by the public key request unit 121 in S701. The number is transmitted to request the provision of the public key P1 of the sender A.
[0070]
The certificate authority CA side apparatus 115 identifies the sender A registered in the public key database 119 by the ID number received in S702, and transmits the public key P1 of the sender A to the receiver B side apparatus 120.
[0071]
The receiver B side device 120 acquires the public key P1 of the sender A from the certificate authority CA side device 115 in S703. In step S <b> 704, the correction information request unit 503 transmits the ID number added to the electronic document E to the registration station RA side device 108 to request the sender A to provide correction information R <b> 1.
[0072]
The registration station RA side apparatus 108 transmits the latest correction information R1 of the sender A registered in the personal information database 114 by the key correction information providing unit 502 in S705 to the receiver B side apparatus 120. At this time, in order to prevent reuse of the secret key S2, the correction information providing unit 502 deletes the correction information R1 from the personal information database 114.
[0073]
The receiver B side device 120 acquires the correction information R1 from the registration station RA side device 108 in S706. In step S707, the public key correction unit 504 corrects the public key P1. The public key P2 obtained by the correction is calculated by the following formula 2 using the public key P1 of the sender A acquired from the certification authority CA and the latest correction information R1 of the sender A acquired from the registration authority RA. It is.
[0074]
[Expression 2]

[0075]
Next, the hash value calculated by the sender A by decrypting the digital signature G1 added to the electronic document E received from the sender A using the public key P2 of the sender A calculated by the signature confirmation unit 122 in S708 is obtained. At the same time, the function information F is decrypted using the public key P2 of the sender A, the hash value of the received electronic document E is calculated using the function specified thereby, and the two hash values are compared. This confirms that the sender is the A person.
[0076]
As described above, according to the second embodiment of the present invention, since the registration authority RA newly generates the secret key S2 during the signature generation process, the secret key used in the past signature generation process is repeatedly used. Can be prevented. Therefore, unauthorized use (for example, impersonation) of a third party due to leakage of the secret key can be avoided. Moreover, since the receiver B needs to acquire the sender A's public key P1 and the correction information R1 from different organizations, the confidentiality of the process of encrypting and decrypting the information may be strictly concealed. System security can be improved.
[0077]
<Third embodiment>
In the third embodiment, the secret key is reused up to N times. In accordance with this, the correction information providing unit 502 is appropriately adjusted in consideration of the security level required by the system and user convenience.
[0078]
FIG. 10 is a block diagram of the third embodiment. In the third embodiment, an access counter unit 1001 is added to the registration station RA side device 108 with respect to the second embodiment.
[0079]
The access counter unit 1001 is a part that records the number of secret keys provided to the sender A side device 101 from the registration authority RA side device 108 and the number of correction information provided to the receiver B side device 120.
[0080]
The operation of the third embodiment is different from that of the second embodiment during the signature generation process. Therefore, this operation will be described below with reference to FIG. FIG. 11 is a flowchart of the signature generation process.
[0081]
The sender A apparatus 101 first acquires the biometric feature information D of the sender A by the biometric feature acquisition unit 102 in S1101. In step S1102, the common key generation unit 103 generates a common key C2. The common key C2 may be different from the common key C1 used at the time of user (sender) registration processing of the sender A, and a random number or the like can be used. In step S <b> 1103, the public key encryption unit 104 encrypts the biometric feature information D and the common key C <b> 2 using the public key encryption P <b> 0 of the registration authority RA, and transmits it to the registration authority RA side apparatus 108.
[0082]
The registration authority RA side device 108 uses its private key S0 by the private key decryption unit 109 in S1104. Sender A side device 101 The biometric feature information D and the common key C2 transmitted from are decrypted. In step S <b> 1105, the identity verification unit 110 verifies the biometric feature information D transmitted from the sender A side device 101 and the biometric feature information D registered in the personal information database 114 to perform identity verification. When the identity is confirmed, in S1106, it is checked whether the number of times of providing the latest secret key S2 of the sender A recorded in the access counter unit 1001 is within a predetermined number. If it is within the predetermined number, the count number recorded in the access counter unit 1001 is incremented by 1 in S1107, and the operation proceeds to S1111. A certain number of times Beyond If so, the operation proceeds to S1108.
[0083]
In S1108, the private key / public key generation unit 111 newly generates the private key S2 and the public key P2 of the sender A. These keys are preferably different from the secret key or public key generated at the time of registration of the sender A or the previous signature generation process. In step S <b> 1109, the correction information generation unit 501 generates correction information R <b> 1 and registers it in the personal information database 114. The correction information R1 is calculated by the following equation 3 using the newly generated public key P2 of the sender A and the public key P1 of the sender A registered in the personal information database. The correction information R1 registered in the personal information database 114 is always only the latest information.
[0084]
[Equation 3]

[0085]
Next, in S1110, the count number of the access counter unit 1001 is initialized, that is, set to zero.
[0086]
Next, in S1111, the common key encryption unit 112 encrypts the secret key S2 using the common key C2, and transmits it to the sender A side apparatus 101.
[0087]
In S1112, the sender A side apparatus 101 uses the common key decryption unit 105 to decrypt the secret key S2 received from the registration authority RA side apparatus 108 using the common key C2. In step S1113, the signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function, encrypts the hash value using the secret key S1, and generates the digital signature G1. The function information F also includes the secret key. Encrypt using S1. Then, the ID number, the encrypted digital signature G1 and the function information F are added to the electronic document E and transmitted to the receiver B side device 120.
[0088]
As described above, according to the third embodiment of the present invention, the key generated by one identity verification can be used for a plurality of signatures only within a predetermined number of times. It is possible to increase the speed of providing the key in the secured state, and to improve the convenience of the system.
[0089]
<Fourth embodiment>
In the fourth embodiment, the registration station RA side apparatus 108 manages the number of diversions of the issued secret key S2 in the third embodiment, whereas the sender A side apparatus 101 manages it. .
[0090]
FIG. 12 is a block diagram of the fourth embodiment. In the fourth embodiment, a secret key storage unit 1201 is added to the sender A side device 108 compared to the third embodiment.
[0091]
The secret key storage unit 1201 is a part that records the secret key S2 provided from the registration authority RA side device 108 to the sender A side device 101. The sender A apparatus 101 uses the secret key S2 recorded in the secret key storage unit 1201 to generate the digital signature G1. The sender A side apparatus 101 counts the number of times the secret key S2 recorded in the secret key storage unit 1201 is used by the signature generation unit 106. When the number of diversions exceeds a predetermined number, the sender A side apparatus 101 acquires the biometric feature information D of the sender A and transmits it to the registration station RA side apparatus 108, and the registration station RA side apparatus 108 causes the sender A to generate a new secret key S2.
[0092]
The operation of the fourth embodiment is different from that of the third embodiment at the time of signature generation processing and signature confirmation processing. Therefore, these operations will be described below.
[0093]
First, the operation during the signature generation process will be described with reference to FIG. FIG. 13 is a flowchart of the signature generation process.
[0094]
The sender A side apparatus 101 first determines whether or not to use the issued secret key S2 of the sender A recorded in the secret key storage unit 1201 in S1301. If diverted, the private key S2 of the sender A is read from the private key storage unit 1201 in S1302, and the operation proceeds to S1314. If not diverted, the operation proceeds to S1303.
[0095]
In step S1303, the biometric feature acquisition unit 102 acquires the biometric feature information D of the sender A. In step S1304, the common key generation unit 103 generates a common key C2. The common key C2 may be different from the common key C1 used at the time of user (sender) registration processing of the sender A, and a random number or the like can be used. In step S1305, the public key encryption unit 104 encrypts the biometric feature information D and the common key C2 using the public key encryption P0 of the registration authority RA, and transmits it to the registration authority RA side apparatus 108.
[0096]
The registration authority RA side device 108 uses its private key S0 by the private key decryption unit 109 in S1306. Sender A side device 101 The biometric feature information D and the common key C2 transmitted from are decrypted. In step S <b> 1307, the identity verification unit 110 compares the biometric feature information D transmitted from the sender A side apparatus 101 with the biometric feature information D registered in the personal information database 114 to perform identity verification.
[0097]
When the user is confirmed, the private key / public key generation unit 111 newly generates the private key S2 and the public key P2 of the sender A in S1308. These keys are preferably different from the secret key or public key generated at the time of registration of the sender A or the previous signature generation process. In step S1309, the correction information generation unit 501 generates correction information R1 and registers it in the personal information database 114. The correction information R1 is calculated by the following equation 4 using the newly generated public key P2 of the sender A and the public key P1 of the sender A registered in the personal information database. The correction information R1 registered in the personal information database 114 is always only the latest information.
[0098]
[Expression 4]

[0099]
In step S1310, the count number of the access counter unit 1001 is initialized, that is, set to zero.
[0100]
Next, in S1311, the common key encryption unit 112 encrypts the secret key S2 using the common key C2, and transmits it to the sender A side apparatus 101.
[0101]
In S1312, the sender A side apparatus 101 uses the common key decryption unit 105 to decrypt the secret key S2 received from the registration authority RA side apparatus 108 using the common key C2. In S1313, the secret key S2 is recorded in the secret key storage unit 1201. Next, in S1314, the signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function and encrypts it using the private key S1 to generate the digital signature G1, and the function information F also includes the private key. Encrypt using S1. Then, the ID number, the encrypted digital signature G1 and the function information F are added to the electronic document E and transmitted to the receiver B side device 120.
[0102]
In subsequent signature generation processing operations, operations from S1303 to S1313 can be omitted by using the secret key S2 stored in the secret key storage unit 1201. In this case, the sender A side apparatus 101 determines whether or not the secret key S2 is to be diverted (that is, whether to newly generate the registration station RA side apparatus 108) based on the number of diversions of the secret key S2. become.
[0103]
Next, the operation at the time of signature confirmation processing will be described with reference to FIG. FIG. 14 is a flowchart of the signature confirmation process. In this embodiment, the registration station RA side device 108 counts the number of requests for providing the correction information R1 of the sender A from the receiver B side device 120. When the number of requests exceeds the predetermined number, the registration station RA side device 108 stops providing the correction information R1 of the sender A to the receiver B side device 120. As a result, the registration station RA side device 108 ensures the security of the system above a certain level.
[0104]
When the electronic document E and the digital signature are transmitted from the sender A side apparatus 101, the receiver B side apparatus 120 transmits the ID added to the electronic document E to the certification authority CA by the public key request unit 121 in S1401. The number is transmitted to request the provision of the public key P1 of the sender A.
[0105]
The certificate authority CA side apparatus 115 identifies the sender A registered in the public key database 119 by the ID number received in S1402, and transmits the public key P1 of the sender A to the receiver B side apparatus 120.
[0106]
The receiver B side apparatus 120 acquires the public key P1 of the sender A from the certificate authority CA side apparatus 115 in S1403. In step S <b> 1404, the correction information request unit 503 transmits the ID number added to the electronic document E to the registration station RA side device 108 to request the sender A to provide correction information R <b> 1.
[0107]
In step S <b> 1405, the registration authority RA side device 108 checks whether the number of times the latest correction information R <b> 1 of the sender A recorded in the access counter unit 1001 is within a predetermined number. If it is within the predetermined number of times, the count number recorded in the access counter unit 1001 is incremented by one, and the operation proceeds to S1206. If the predetermined number of times is exceeded, the correction information R1 of the sender A cannot be provided. Is transmitted to the receiver B side device 120.
[0108]
In step S <b> 1406, the key correction information providing unit 502 transmits the latest correction information R <b> 1 of the sender A registered in the personal information database 114 to the receiver B side device 120. At this time, when the number of times of providing the latest correction information R1 of the sender A recorded in the access counter unit 1001 reaches a predetermined number, the correction information providing unit 502 is used to prevent reuse of the secret key S2. Deletes the correction information R1 from the personal information database 114.
[0109]
The receiver B side device 120 acquires the correction information R1 from the registration station RA side device 108 in S1407. In step S1408, the public key correction unit 504 corrects the public key P1. The public key P2 obtained by the correction is calculated by the following equation 5 using the public key P1 of the sender A acquired from the certification authority CA and the latest correction information R1 of the sender A acquired from the registration authority RA. It is.
[0110]
[Equation 5]

[0111]
In step S1409, the digital signature G1 added to the electronic document E received from the sender A is decrypted using the sender A public key P2 calculated by the signature confirmation unit 122, and the hash value calculated by the sender A is obtained. At the same time, the function information F is decrypted using the public key P2 of the sender A, the hash value of the received electronic document E is calculated using the function specified thereby, and the two hash values are compared. This confirms that the sender is the A person.
[0112]
As described above, according to the fourth embodiment of the present invention, the sender A side apparatus 101 diverts the previously acquired key to generate the digital signature G1. Therefore, since the sender A side apparatus 101 does not need to communicate with the registration station RA side apparatus 108, electronic information can be provided to the receiver B side apparatus 120 earlier than the third embodiment.
[0113]
<Fifth embodiment>
In the fifth embodiment, the secret key can be reused only within a predetermined time. In accordance with this, the correction information providing unit 502 is appropriately adjusted in consideration of the security level required by the system and user convenience.
[0114]
FIG. 15 is a block diagram of the fifth embodiment. The fifth embodiment is different from the third embodiment in that a time recording unit 1501 is provided instead of the access counter unit 1001.
[0115]
The time recording unit 1501 is a part that records the time when the secret key was generated from the RA authority 108 on the registration authority side 108 to the sender A side apparatus 101, the time provided, the time when correction information was provided to the receiver B side apparatus 120, and the like. is there.
[0116]
The operation of the fifth embodiment is different from that of the third embodiment during the signature generation process. Therefore, this operation will be described below with reference to FIG. FIG. 16 is a flowchart of the signature generation process.
[0117]
The sender A-side apparatus 101 first acquires the biometric feature information D of the sender A by the biometric feature acquisition unit 102 in S1601. In step S1602, the common key generation unit 103 generates a common key C2. The common key C2 may be different from the common key C1 used at the time of user (sender) registration processing of the sender A, and a random number or the like can be used. In step S1603, the public key encryption unit 104 encrypts the biometric feature information D and the common key C2 using the public key encryption P0 of the registration authority RA, and transmits it to the registration authority RA side apparatus 108.
[0118]
The registration authority RA side device 108 uses its private key S0 by the private key decryption unit 109 in S1604. Sender A side device 101 The biometric feature information D and the common key C2 transmitted from are decrypted. In step S <b> 1605, the identity verification unit 110 compares the biometric feature information D transmitted from the sender A-side device 101 with the biometric feature information D registered in the personal information database 114 to perform identity verification. If it is confirmed that it is the principal, in S1606, it is checked whether the current time is within a predetermined time from the time when the latest secret key S2 of the sender A recorded in the time recording unit 1301 is generated. If it is within the predetermined time, the operation proceeds to S1609. Predetermined time Beyond If so, the operation proceeds to S1607.
[0119]
In S1607, the secret key / public key generation unit 111 newly generates the secret key S2 and the public key P2 of the sender A. These keys are preferably different from the secret key or public key generated at the time of registration of the sender A or the previous signature generation process. In step S1608, the correction information generation unit 501 generates correction information R1 and registers the correction information R1 in the personal information database 114. The correction information R1 is calculated by the following equation 6 using the newly generated public key P2 of the sender A and the public key P1 of the sender A registered in the personal information database. The correction information R1 registered in the personal information database 114 is always only the latest information.
[0120]
[Formula 6]

[0121]
In step S1609, the time recording unit 1501 records the time. At this time, if the operation proceeds from S1606, the time recording unit 1501 records the time when the latest secret key S2 of the sender A is provided to the sender A side device 101, and the operation proceeds from S1608. If so, the time when the latest secret key S2 of the sender A is generated is recorded.
[0122]
Next, in S1610, the common key encryption unit 112 encrypts the secret key S2 using the common key C2, and transmits it to the sender A side apparatus 101.
[0123]
In S1611, the sender A side apparatus 101 uses the common key decryption unit 105 to decrypt the secret key S2 received from the registration authority RA side apparatus 108 using the common key C2. Next, in S1612, the signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function, encrypts the hash value using the secret key S1, and generates the digital signature G1, and the function information F also includes the secret key. Encrypt using S1. Then, the ID number, the encrypted digital signature G1 and the function information F are added to the electronic document E and transmitted to the receiver B side device 120.
[0124]
As described above, according to the fifth embodiment of the present invention, a key generated by one identity verification can be used for a plurality of signatures only within a predetermined time. It is possible to increase the speed of providing the key in the secured state, and to improve the convenience of the system.
[0125]
<Sixth embodiment>
In the sixth embodiment, the registration station RA side apparatus 108 manages the time when the issued secret key S2 is diverted in the fifth embodiment, whereas the sender A side apparatus 101 manages the time. is there.
[0126]
FIG. 17 is a block diagram of the sixth embodiment. In the sixth example, a secret key storage unit 1701 is added to the sender A side apparatus 108 compared to the fifth example.
[0127]
The secret key storage unit 1701 is the same part as the secret key storage unit 1201 described in the fourth embodiment. That is, the secret key storage unit 1701 is a part that records the secret key S2 provided from the registration authority RA side device 108 to the sender A side device 101. The sender A side apparatus 101 uses the secret key S2 recorded in the secret key storage unit 1701 to generate the digital signature G1. The sender A side apparatus 101 monitors the time when the signature generation unit 106 records the secret key S2 in the secret key storage unit 1201. When a predetermined time has elapsed from the recorded time, the sender A side apparatus 101 acquires the biometric feature information D of the sender A and transmits it to the registration station RA side apparatus 108 to register the registration station RA. The side device 108 is caused to generate a new secret key S2 of the sender A.
[0128]
The operation of the sixth embodiment is different from that of the fifth embodiment during signature generation processing and signature confirmation processing. Therefore, these operations will be described below.
[0129]
First, the operation during signature generation processing will be described with reference to FIG. FIG. 18 is a flowchart of the signature generation process.
[0130]
The sender A side apparatus 101 first determines whether to use the issued secret key S2 of the sender A recorded in the secret key storage unit 1701 in S1801. If diverted, the private key S2 of the sender A is read from the private key storage unit 1701 in S1802, and the operation proceeds to S1814. If not diverted, the operation proceeds to S1803.
[0131]
In S1803, the biometric feature acquisition unit 102 acquires the biometric feature information D of the sender A. In step S1804, the common key generation unit 103 generates a common key C2. The common key C2 may be different from the common key C1 used at the time of user (sender) registration processing of the sender A, and a random number or the like can be used. In step S1805, the public key encryption unit 104 encrypts the biometric feature information D and the common key C2 using the public key encryption P0 of the registration authority RA, and transmits the encrypted information to the registration authority RA side apparatus 108.
[0132]
The registration authority RA side device 108 uses the private key S0 by the private key decryption unit 109 in S1806. Sender A side device 101 The biometric feature information D and the common key C2 transmitted from are decrypted. In step S <b> 1807, the identity verification unit 110 verifies the biometric feature information D transmitted from the sender A side apparatus 101 with the biometric feature information D registered in the personal information database 114 to perform identity verification.
[0133]
When the user is confirmed, the private key / public key generation unit 111 newly generates the private key S2 and the public key P2 of the sender A in S1808. These keys are preferably different from the secret key or public key generated at the time of registration of the sender A or the previous signature generation process. In step S 1809, the correction information generation unit 501 generates correction information R 1 and registers it in the personal information database 114. The correction information R1 is calculated by the following equation 7 using the newly generated public key P2 of the sender A and the public key P1 of the sender A registered in the personal information database. The correction information R1 registered in the personal information database 114 is always only the latest information.
[0134]
[Expression 7]

[0135]
In step S1810, the time recording unit 1301 records the time when the latest secret key S2 of the sender A is generated.
[0136]
Next, in S1811, the common key encryption unit 112 encrypts the secret key S2 using the common key C2, and transmits it to the sender A side apparatus 101.
[0137]
In S1812, the sender A side apparatus 101 uses the common key decryption unit 105 to decrypt the secret key S2 received from the registration authority RA side apparatus 108 using the common key C2. In S1813, the secret key S2 is recorded in the secret key storage unit 1201. The time at this time is also recorded in the secret key storage unit 1201. In step S1814, the signature generation unit 106 calculates a hash value of the electronic document E using an arbitrary function, encrypts the hash value using the secret key S1, and generates the digital signature G1. The function information F also includes the secret key. Encrypt using S1. Then, the ID number, the encrypted digital signature G1 and the function information F are added to the electronic document E and transmitted to the receiver B side device 120.
[0138]
In subsequent signature generation processing operations, operations from S1803 to S1813 can be omitted by using the secret key S2 stored in the secret key storage unit 1701. In this case, whether the secret key S2 is diverted or not (that is, whether the registration station RA side apparatus 108 newly generates it) is an elapsed time after the sender A side apparatus 101 receives the provision of the secret key S2. Judgment based on.
[0139]
Next, the operation at the time of signature confirmation processing will be described with reference to FIG. FIG. 19 is a flowchart of the signature confirmation process. In this embodiment, the registration station RA side device 108 monitors the time when the receiver B side device 120 requests to provide the correction information R1 of the sender A. When a predetermined time has elapsed since the time when the private key S2 of the sender A was provided to the sender A side apparatus 101, the registration authority RA side apparatus 108 transmits the sender A to the receiver B side apparatus 120. The provision of the correction information R1 is stopped. As a result, the registration station RA side device 108 ensures the security of the system above a certain level.
[0140]
When the electronic document E and the digital signature are transmitted from the sender A side device 101, the receiver B side device 120 transmits the ID added to the electronic document E to the certification authority CA by the public key request unit 121 in S1901. The number is transmitted to request the provision of the public key P1 of the sender A.
[0141]
The certificate authority CA side device 115 identifies the sender A registered in the public key database 119 by the ID number received in S1902, and transmits the public key P1 of the sender A to the receiver B side device 120.
[0142]
The receiver B side device 120 acquires the sender A public key P1 from the certificate authority CA side device 115 in S1903. In step S1904, the correction information request unit 503 transmits the ID number added to the electronic document E to the registration station RA side apparatus 108 to request the sender A to provide correction information R1.
[0143]
In step S1905, the registration authority RA side device 108 checks whether or not it is within a predetermined time from the time when the sender A's private key S2 is provided to the sender A side device 101. If it is within the predetermined time, the operation proceeds to S1906, and if the predetermined time has elapsed, the fact that the correction information R1 of the sender A cannot be provided is transmitted to the receiver B side device 120. If the predetermined time has elapsed, the correction information providing unit 502 deletes the correction information R1 from the personal information database 114 in order to prevent reuse of the secret key S2.
[0144]
In step S1906, the key correction information providing unit 502 transmits the latest correction information R1 of the sender A registered in the personal information database 114 to the receiver B side device 120.
[0145]
The receiver B side device 120 acquires the correction information R1 from the registration station RA side device 108 in S1907. In step S1908, the public key correction unit 504 corrects the public key P1. The public key P2 obtained by the correction is calculated by the following equation 8 using the public key P1 of the sender A acquired from the certification authority CA and the latest correction information R1 of the sender A acquired from the registration authority RA. It is.
[0146]
[Equation 8]

[0147]
Next, the hash value calculated by the sender A by decrypting the digital signature G1 added to the electronic document E received from the sender A using the public key P2 of the sender A calculated by the signature confirmation unit 122 in S1909 is obtained. At the same time, the function information F is decrypted using the public key P2 of the sender A, the hash value of the received electronic document E is calculated using the function specified thereby, and the two hash values are compared. This confirms that the sender is the A person.
[0148]
As described above, according to the sixth embodiment of the present invention, the sender A side apparatus 101 diverts the previously acquired key to generate the digital signature G1. Therefore, since the sender A side apparatus 101 does not need to communicate with the registration station RA side apparatus 108, electronic information can be provided to the receiver B side apparatus 120 earlier than the fifth embodiment.
[0149]
The present invention is not limited to the above-described embodiments, and various applications and modifications can be considered without departing from the gist of the present invention.
[0150]
For example, the present invention can be used as a mechanism for guaranteeing various electronic information issuers. For example, it can be used for a mechanism for guaranteeing an issuer of an order form in electronic commerce, an issuer of a public document such as a family register copy or a resident's card, and an electronic information issuer in an electronic application by a network.
[0151]
Further, the registration station RA side apparatus can generate the private key S1, public key P1, and correction information R1 of the sender A using the biometric feature information D of the sender A registered in the personal information database 114. It is. As shown in FIG. 8, the biometric feature information D of the sender A is registered in the personal information database 114.
[0152]
For example, in the case of the name “Taro Yamada”, the biometric feature information D is “1011100010010”. The biometric feature information D has a size of several tens to several hundreds of bytes when acquired from an iris as in this embodiment. With this size information, various values can be extracted. For example, the number of values “1” (six in the case of the name “Taro Yamada” in the example of FIG. 8) or the value “0”. ”(Same as 6), the number of locations where the value“ 1 ”continues (same as 1), the number of locations where the value“ 0 ”continues (same as 2), and the like can be extracted. . Therefore, the registration station RA side apparatus can generate the private key S1, the public key P1, and the correction information R1 of the sender A using the biometric feature information D based on an arbitrary algorithm.
[0153]
Further, when the system is configured to be usable by performing identity verification using the biometric feature information D, an authentication device that performs identity verification can play the role of the registration authority RA. In the system configured as described above, the biometric feature information D is acquired when the system becomes available. If the biometric feature information D is transmitted to the registration authority RA at this time, the signature generation process is performed. Sometimes the step of obtaining the biometric feature information D can be omitted.
[0154]
In the above embodiment, the sender A side apparatus 101 uses the common keys C1 and C2 when receiving the secret keys S1 and S2 from the registration station RA side apparatus 108. Instead, it is possible to use public keys P1, P2 and others. For example, the sender A separately generates a new secret key S ′ and a public key P ′ and transmits the public key P ′ to the registration station RA. The registration station RA uses the public key P ′ to transmit the secret key S ′. 'Is encrypted and transmitted to the sender A. The sender A can decrypt the secret key S ′ transmitted from the registration authority RA and generate a digital signature using the decrypted secret key S ′.
[0155]
Further, although the certificate authority CA side device 115 and the receiver B side device 120 use the ID number as the information for specifying the sender, it is also possible to use biometric feature information or other information.
[0156]
In the above embodiment, the identity verification in the registration authority RA is performed using the biometric feature information D, but it is also possible to use a conventionally used password or IC card instead. is there.
[0157]
【The invention's effect】
The present invention described above has the following effects.
[0158]
That is, the sender A can save the trouble of issuing the secret key or the public key, and can eliminate the trouble of strictly managing its own secret key. Therefore, the convenience of communication using a digital signature can be improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a first embodiment.
FIG. 2 is a flowchart of user registration processing.
FIG. 3 is a flowchart of a signature generation process.
FIG. 4 is a flowchart of a signature confirmation process.
FIG. 5 is a configuration diagram of a second embodiment.
FIG. 6 is a flowchart of a signature generation process.
FIG. 7 is a flowchart of a signature confirmation process.
FIG. 8 is a diagram showing a flow of information.
FIG. 9 is a diagram showing a flow of information.
FIG. 10 is a configuration diagram of a third embodiment.
FIG. 11 is a flowchart of a signature generation process.
FIG. 12 is a configuration diagram of a fourth embodiment.
FIG. 13 is a flowchart of a signature generation process.
FIG. 14 is a flowchart of a signature confirmation process.
FIG. 15 is a block diagram of a fifth embodiment.
FIG. 16 is a flowchart of a signature generation process.
FIG. 17 is a block diagram of a sixth embodiment.
FIG. 18 is a flowchart of a signature generation process.
FIG. 19 is a flowchart of a signature confirmation process.
[Explanation of symbols]
101 Sender A side device
102 Biometric feature acquisition unit
103 Common key generator
104 Public key encryption unit
105 Common key decryption unit
106 Signature generation unit
107 Communication Department
108 Registration station RA side equipment
109 Secret key decryption unit
110 Identity Confirmation Department
111 Private key / public key generator
112 Common key encryption unit
113 Communication Department
114 Personal information database
115 Certificate Authority CA side device
116 Public Key Registration Department
117 Public key provider
118 Communication Department
119 public key database
120 Receiver B side device
121 Public key request part
122 Signature confirmation part
123 communication unit

Claims (4)

In the provider confirmation system in which the person who acquired the electronic information confirms the provider of the electronic information from the digital signature added to the electronic information,
A registration station side device that acquires provider-specific information and generates a provider's private key and public key, and registers the generated provider's private key;
A provider-side device that generates an encrypted digital signature using the provider's private key generated by the registration authority-side device, and adds the generated digital signature to electronic information;
A certificate authority side device that registers the provider's public key and provides the provider's public key to the electronic information acquirer;
The provider's public key is acquired from the certificate authority side device based on the information specifying the provider added to the electronic information, and is added to the electronic information using the acquired provider's public key An acquirer side device for decrypting the digital signature ;
When the registration authority side device generates the provider's new private key and public key, the registration authority side device transmits the provider's new secret key to the provider side device and issues the provider's new public key and provider Register the correction information that has calculated the difference with the already published public key,
The acquirer-side device acquires a provider's issued public key from the certification authority-side device, and corrects the provider's issued public key by acquiring correction information from the registration authority-side device. A provider confirmation system characterized in that the provider's new public key is obtained . The provider registration system according to claim 1, wherein the registration station side device can transmit correction information to the acquirer side device only within a predetermined number of times or within a predetermined time . In the provider confirmation method in which the person who acquired the electronic information confirms the provider of the electronic information from the digital signature added to the electronic information,
A step in which a provider-side device transmits provider-specific information to a registration authority-side device that generates a secret key and a public key;
The registration station side device generating a provider's private key and public key;
Registering the provider's private key generated by the registration station side device with itself;
The provider side device acquires the provider's private key from the registration authority side device, generates an encrypted digital signature using the acquired provider's private key, and electronically converts the encrypted digital signature Adding to the information,
The acquirer-side device requests the provider's public key from the certificate authority-side device in which the provider's public key generated by the registration authority-side device is registered; and
The certificate authority side device transmitting the provider's public key to the acquirer side device; and
The acquirer side device decrypting the digital signature added to the electronic information using the provider's public key,
When the registration authority side device generates the provider's new secret key and public key, the registration authority side device transmits the provider's new secret key to the provider side device and issues the provider's new public key and provider's issue Register the correction information that calculates the difference with the already-existing public key,
The acquirer-side device acquires the provider's issued public key from the certification authority-side device, and corrects the provider's issued public key by acquiring correction information from the registration authority-side device. And obtaining a new public key of the provider. 4. The provider confirmation method according to claim 3, wherein the registration station side device can transmit the correction information to the acquirer side device only within a predetermined number of times or within a predetermined time.

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