JPH09114719A - Information recording business card and file transfer system using the card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distribute a public key and to prevent wire tapping, dishonest alteration and impersonation to another person by utilizing a magnetically recorded business card in which the public key of a public key cipher system is recorded in a ciphered electronic mail system. SOLUTION: A transmitter acquires a magnetically recorded business card in which the public key of an opposite party for performing ciphered electronic mail communication is recorded at the time of exchanging the business cards, reads the recorded public key in a magnetic information reader 11, prepares a cryptographic key for ciphering an electronic mail by a cryptographic key preparation part 13, ciphers the cryptographic key by using the public key and transmits the ciphered cryptographic key and the ciphered electronic mail. A receiver deciphers the ciphered cryptographic key by his/her own secret key and deciphers the ciphered electronic mail by using the cryptographic key.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryptographic transmission technique that prevents others from knowing the contents of a transmitted file when the created file is transmitted to a destination, and a key used for encryption and decryption is provided. The present invention relates to a system that uses an information recording business card to securely transmit from a transmission source to a transmission destination.
Preferably, it can be used for sending and receiving e-mail and FAX.

[0002]

2. Description of the Related Art Conventionally, there is a technique of transmitting a created document or the like to a destination via an information transmission network using a telephone line or an optical fiber. Today, we simply set the source and destination to 1
Not only is the connection made on a one-to-one basis to transfer files, but many terminal stations are connected via a relay station, such as the Internet, and the sender sends the created file to the relay station, There are also those that allow files to be transmitted to the destination. That is an e-mail system that creates and sends e-mail.

However, the following problems have occurred with the spread of this system. That is, when the source and the destination are connected on a one-to-one basis, if the file is mistakenly connected to a different address and the file is transmitted, the content of the file will be known to others, and In some cases, the secret cannot be kept. Also, the file may be seen by others other than the destination. Moreover, the file may be tampered with by someone, and another person may read the file without knowing the fact of the tampering. It is also possible to impersonate another person and send the file. Furthermore, it is possible to buy and sell products using an electronic mail system and use a credit card to pay the price, and at that time, it is conceivable to write the card number in the electronic mail. In particular, the card number is highly confidential and may be misused if it is known to others.

[0004]

Therefore, in the above-mentioned file transfer system (e-mail system, etc.), in order to prevent others from knowing the contents of the file, the file is encrypted and transmitted, and the destination is It is necessary to adopt the technique of deciphering it. Internet standardized document RF as a system for sending and receiving encrypted e-mail
C-1421, 1422, 1423, 1425 with PEM
(Privacy Enhanced Mail) is proposed. PEM
Enhances email security by encrypting messages to prevent eavesdropping and introducing digital signatures to prevent falsification at the relay station and impersonation by others. In addition, the user's public key can be trusted by
By using a public key certificate (Public key certificate) certified by icationAuthority) to manage a user's key, an attack that falsifies the public key itself and impersonates another person is prevented.

However, in the PEM, since the public key is managed by the issuing station, a person who wants to send and receive a file needs to register his public key in the issuing station in advance. Therefore, the registration work is troublesome,
The current situation is that it takes time. Also,
Since the public key of the person you want to communicate with will be received via the network, in order to eliminate the risk of forgery at the time of distributing the public key, have the issuing authority issue a public key certificate. The public key certificate and the public key certificate are sent to the destination via the network.

[0006] Further, in the actual transmission of electronic mail, an encryption key that has been encrypted by the public key method is used as the encryption key used when the mail body was encrypted by the conventional key method in the header section of the mail, and Since it is decided to attach the public key certificate of the public key used in the processing of the public key cryptosystem, there is a problem that the communication data amount increases.

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to eliminate the troublesome work of registering a public key in an issuing authority and only to a partner who wants to communicate. An object of the present invention is to provide an information recording business card capable of reliably distributing a public key and reducing the amount of communication data, and a file transfer system using the same.

[0008]

In order to achieve this object, an information recording business card according to claim 1 is a business card printing section on which business card information such as a name of a business card holder and a telephone number is printed.
The business card printing unit includes an information recording unit that records a public key for performing encrypted communication with the business card holder by the public key system. Therefore, the public key can be directly transmitted without going online.

In the file transfer system using the information recording business card according to the second aspect, the information recording business card is handed in advance to the other party with whom communication is desired by exchanging the business card. The other party (transmission source) who has received the information recording business card transmits the public key recorded in the information recording section of the magnetic recording business card by the reading means when transferring the file with the business card owner (transmission destination). Read. Further, the encryption key creating means creates an encryption key of the conventional encryption method, and the file encryption means encrypts the file to be transmitted using the encryption key. The encryption key encryption means encrypts the encryption key created by the encryption key creating means using the public key read by the reading means. After this, the transmission means transmits the encryption key encrypted by the encryption key encryption means and the file encrypted by the file encryption means.

On the other hand, at the transmission destination, the secret key corresponding to the public key is stored in the secret key storage means, and the encrypted encryption key received by the encryption key decryption means is used as the secret key. Then, the file is decrypted, and the received file is decrypted using the encryption key decrypted by the file decryption means. Therefore, by handing the public key to the other party in the form of business card exchange in advance, the public key is issued to the issuing authority (network).
It is possible to send and receive public keys without going through. For this reason, the possibility of forgery of the public key that occurs when passing through the network is eliminated, and since it is not necessary to create a public key certificate, the amount of communication data can be reduced.

In the file transfer system using the information recording business card according to the third aspect, the encryption key creating means of the transmission source randomly creates the encryption key for each transmission, so that the encryption key is generated every time communication is performed. It will be changed, and the safety will be improved.

In the file transfer system using the information recording business card according to the fourth aspect, the address information of the business card holder is further recorded in the information recording section of the information recording business card, and the reading means of the transmission source is Address information is read together with the public key, and the transmission means reads the encryption key encrypted by the encryption key encryption means and the file encrypted by the file encryption means. Since it is configured to send to the address described above, the file automatically created by simply reading the information recording part of the information recording business card with the reading means is the destination (name card owner).
Can be sent to.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

First, a magnetic recording business card (information recording business card) of the present invention will be described.

FIG. 1A is a plan view showing the surface of a magnetic recording business card. As shown in the figure, normal business card description items such as company name, job title, name (name of business card owner), and telephone number are printed, and the card itself has a function as a business card.

FIG. 1B is a plan view showing the back surface of the magnetic recording business card. As shown in the drawing, a magnetic track as an information recording portion is provided in a strip shape, and its position and dimensions are as specified in JISB9561. The public key of the public key cryptosystem and the electronic mail address are magnetically recorded in advance on this magnetic track. The magnetic track can be formed not only on the back surface of the magnetic recording business card but also on the front surface thereof. Further, the magnetic track may be formed on the entire front surface or back surface.
Further, instead of magnetically recording the public key and the electronic mail address on a magnetic track, it is possible to form a memory circuit and a connector on an information recording business card like an IC card to store information in the memory circuit. Is.

Next, an electronic mail system (file transfer system) using the magnetic recording business card of the present invention will be described.

The cryptographic algorithm used in this embodiment is RSA (Rivest-Shamir-Adelma) for the public key cryptosystem.
n) DES (data encryption standard) encryption is used for the encryption and the conventional encryption method.

FIG. 2 is a block diagram of an electronic mail system using a magnetic recording business card according to the present embodiment. The figure shows a block diagram of a terminal station connected to a public telephone line or a dedicated line. This terminal station is common to both the transmission source and the transmission destination of the file transfer system, so only one of them is shown.

The magnetic recording business card reading device section 11 as a reading means is a device for reading the public key and the electronic mail address recorded on the magnetic recording business card. The secret key storage unit 20 as a secret key storage means stores the secret key of the public key cryptosystem held by the user of this terminal station. The public key corresponding to this secret key is recorded in advance on the magnetic track of the magnetic recording business card of the user of the terminal station. By exchanging business cards with users of other terminal stations, these users exchange their public keys. That is, the public key is not distributed via the network, and can be reliably transmitted to the communication partner only by exchanging business cards.

Further, the communication control section 21 executes a transmission control procedure process of electronic mail data. The mail created is sent to the address of the electronic mail recorded on the magnetic track. The communication interface unit 22 is for realizing connection control with an external device or system via a communication line. The communication control unit 21 and the communication interface unit 22 constitute a transmitting means.

The main control unit 12 executes the control process of the entire electronic mail system, controls the reading process of the magnetic recording business card reading unit 11, and processes for encrypting / decrypting data. And control of digital signature processing. The encryption key generation unit 13 as an encryption key generation unit is for generating an encryption key of a conventional encryption method used in encryption transmission, and here, 56b.
A random number of it is generated to create a 64-bit encryption key of DES encryption.

The encryption key generator 13 randomly creates an encryption key each time an encryption is transmitted, but the frequency of creating the encryption key is arbitrary. That is, for example, a new encryption key may be created every one week, or may be created every one month. Therefore, a clock circuit is provided in the main control unit 12, the encryption key is stored together with the creation date, the elapsed days are calculated based on the current date data from the clock circuit and the creation date data, and the elapsed days are calculated. It is also possible to automatically create the encryption key when the number of days exceeds a predetermined number.

The digital signature generation unit 14 calculates a message digest corresponding to the checksum of the text of the electronic mail to be transmitted, and uses the secret key stored in the secret key storage unit 20 to generate a digital signature for this message digest. The digital signature decryption unit 15 decrypts the digital signature received via the communication interface unit 22 using the public key read by the magnetic recording business card reading device unit 11. The encryption key encryption unit 16 as an encryption key encryption unit uses the public key of the destination terminal station read by the magnetic recording business card reading device unit 11 at the time of transmission to generate the encryption key by the encryption key generation unit 13. The encryption key decryption unit 17 as an encryption key decryption means uses the private key stored in the private key storage unit 20 when receiving an electronic mail to communicate with the communication interface. The encrypted encryption key received via the unit 22 is decrypted to the original value.

The data encryption section 18 as the file encryption means executes the encryption processing of the e-mail text by using the encryption key at the time of encryption transmission, and the data decryption section 19 as the file decryption means , Which converts the encrypted electronic mail received via the communication interface unit 22 into the original electronic mail text using an encryption key.

That is, in each terminal station, as the constitution of the transmission source, the magnetic recording business card reading device unit 11, the encryption key generation unit 13, the digital signature generation unit 14, the encryption key encryption unit 16, the data An encryption unit 18 is provided, and the digital signature decryption unit 15, the encryption key decryption unit 17, and the data decryption unit 1 are configured as a destination (reception side).
9 is provided.

The operation of the electronic mail system configured as above will be described with reference to FIGS.

Prior to communication, the sender and the receiver obtain the magnetically recorded business card of the communication partner having the public key recorded by exchanging the business card (S1). The sender (source) who wants to send the encrypted electronic mail is the magnetic recording business card reader 11
Use to read the information on the magnetic recording business card of the recipient (destination) (S2), obtain the recipient's public key and email address, create the email text (S3), and send the encrypted instructions. (S4). At this time, the sender does not need to input the e-mail address of the recipient, and the e-mail address of the recipient read from the magnetic recording business card is designated as the destination.

As shown in FIG. 4, a cryptographic transmission instruction (S1
The main control unit 12 that has received 1) receives the digital signature generation unit 1
In 4, the message digest corresponding to the checksum of the email body is calculated (S12), and the sender's private key stored in the private key storage unit 20 is used to create a digital signature for this message digest (S13). Next, the main control unit 12 uses the encryption key generation unit 13
In step S14, an encryption key for encrypted communication is generated,
The data encryption unit 18 encrypts the email body using the generated encryption key (S15), and the encryption key used to encrypt the email body is read by the magnetic recording business card reading device unit 11. Encryption is performed by the encryption key encryption unit 16 using the public key (S16). The digital signature created by the series of these processes, the encrypted electronic mail text, and the encrypted encryption key are grouped and transmitted by the communication control unit 21 (S).
17).

The recipient is notified of the receipt of the encrypted electronic mail (S
Upon receiving 21), the magnetic recording business card reading device unit 11 is caused to read the information of the magnetic recording business card of the sender (S22), and is instructed to decrypt the encrypted electronic mail (S23). By this instruction, the encrypted electronic mail is decrypted in the system, and the recipient can read the content of the decrypted electronic mail (S24).

Main control unit 1 of recipient's electronic mail system
When the decryption processing instruction is received (S31), the decryption processing 2 decrypts the digital signature of the encrypted electronic mail received by the digital signature decryption unit 15 using the public key read by the magnetic recording business card reading device unit 11 to perform the message digest. (S32), the encrypted encryption key is decrypted by the encryption key decryption unit 17 using the recipient's private key stored in the private key storage unit 20 (S33), and the encryption key is extracted and decrypted. The data decryption unit 19 decrypts the email body encrypted using the encrypted key (S34). Next, the main control unit 12 calculates the message digest of the decrypted e-mail text, checks whether it matches the message digest of the decrypted digital signature (S35), authenticates the sender and the content of the e-mail. It is judged whether or not the data has been tampered with. If the message digests match (S35: Y), it is confirmed that the content of the encrypted email has been correctly received, and the decrypted email body is displayed (S36). If they do not match (S35: N), an error message is displayed (S37).

As described above, according to the present embodiment, the sender and the receiver directly meet each other to exchange the magnetic recording business cards, so that it is possible to prevent spoofing due to forgery of the public key, and the receiver can , It is possible to confirm the authenticity of the sender and the presence or absence of falsification of the content of the received encrypted electronic mail by the digital signature.

In the above-described embodiment, the magnetic recording business card is read every communication, but the magnetic recording business card obtained by exchanging the business card is read in advance and a plurality of information is stored in the electronic mail system. It is also possible to retrieve the public key from the email addresses of the sender and the recipient.

In the above embodiment, the RSA cryptosystem is used as the public key cryptosystem, but other public key cryptosystems may be used, and the DES cryptosystem is used as the conventional cryptosystem, but the FEAL cryptosystem is used. It is also possible to use other conventional encryption methods such as.

In the above description, description of parts that are not directly related to the present invention is omitted.

[0036]

As is apparent from the above description, the information recording business card according to claim 1 is exchanged with each other when exchanging the business card, but the public key of the exchanged information recording business card is surely the business card. This is the public key of the holder of the company, and there is no risk of forgery. Even if it is forged, it will not be possible to carry out encrypted communication with the holder of the business card, so a third party will masquerade as the holder of the business card. It is possible to eliminate the danger. You can certainly pass the public key to the other party you want to communicate with, compared to when using a conventional network,
There is no need to register the public key with the issuing authority,
Moreover, the amount of communication data can be reduced.

Further, in the file transfer system using the information recording business card according to the second aspect, the information recording business card is handed to the other party with whom the user wishes to communicate by exchanging the business card in advance. The other party (transmission source) who has received the information recording business card transmits the public key recorded in the information recording section of the information recording business card by the reading means when transferring the file with the business card owner (transmission destination). Read. Further, the encryption key creating means creates an encryption key of the conventional encryption method, and the file encryption means encrypts the file to be transmitted using the encryption key. The encryption key encryption means encrypts the encryption key created by the encryption key creating means using the public key read by the reading means. After this, the transmission means transmits the encryption key encrypted by the encryption key encryption means and the file encrypted by the file encryption means.

On the other hand, at the transmission destination, the secret key corresponding to the public key is stored in the secret key storage means, and the encrypted encryption key received by the encryption key decryption means is used as the secret key. Then, the file is decrypted, and the received file is decrypted by using the encryption key decrypted by the file decryption means. Therefore, by handing the public key to the other party in the form of business card exchange in advance, the public key can be sent and received without passing through the issuing station which is required when transmitting the public key via the network. For this reason, the possibility of forgery of the public key that occurs when passing through the network is eliminated, and since it is not necessary to create a public key certificate, the amount of communication data can be reduced.

Further, in the file transfer system using the information recording business card according to the third aspect, the encryption key creating means of the transmission source randomly creates the encryption key for each transmission. Will be changed, and the safety will be improved.

Further, in the file transfer system using the information recording business card according to claim 4, address information of the business card holder is further recorded in the information recording section of the information recording business card, and the reading means of the transmission source. Is configured to read the address information together with the public key, and the transmission means reads the encryption key encrypted by the encryption key encryption means and the file encrypted by the file encryption means. Since it is configured to send to the address, the file created by simply reading the information recording unit of the information recording business card with the reading unit can be automatically transmitted to the destination (name card owner).

[Brief description of the drawings]

FIG. 1 (a) is a plan view showing the surface of a magnetic recording business card showing an embodiment of the present invention. FIG. 1 (b)
It is a top view which shows the back surface of the magnetic recording business card which shows one Embodiment of this invention.

FIG. 2 is a block diagram of an electronic mail system showing an embodiment of the present invention.

FIG. 3 is a flowchart of a sender's operation according to the embodiment of the present invention.

FIG. 4 is a flowchart of the operation of the receiving-side electronic mail system according to the embodiment of the present invention.

FIG. 5 is a flowchart of a recipient's operation according to the embodiment of the present invention.

FIG. 6 is a flowchart of the operation of the electronic mail system on the receiving side according to the embodiment of the present invention.

[Explanation of symbols]

 11 Magnetic Recording Business Card Reading Device Section 12 Main Control Section 13 Cryptographic Key Generation Section 14 Digital Signature Generation Section 15 Digital Signature Decryption Section 16 Cryptographic Key Encryption Section 17 Cryptographic Key Decryption Section 18 Data Encryption Section 19 Data Decryption Section 20 Secret Key storage unit 21 Communication control unit 22 Communication interface unit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G09C 1/00 630 7259-5J G09C 1/00 630F 660 7259-5J 660G H04L 9/08 H04L 9 / 00 601B 9/10 601F 621A

Claims (4)

[Claims] 1. A public key method is used for encrypted communication between a business card printing section on which business card information such as a name and a telephone number of a business card holder is printed and a business card holder printed on the business card printing section. An information recording business card consisting of an information recording section in which the public key of is recorded. 2. A file transfer system for cryptographically transmitting a file created at a transmission source to a transmission destination, directly or via a relay station, wherein the transmission source obtains the information recorded business card information from the transmission destination. A reading means for reading the public key from the recording section, an encryption key creating means for creating an encryption key of a conventional key cryptosystem, and a public key read by the reading means for the encryption key created by the encryption key creating means. An encryption key encryption means for encrypting the file to be transmitted using the encryption key created by the encryption key creating means, and an encryption key encryption means for encrypting the file to be transmitted. A private key storage for storing the private key corresponding to the public key at the destination, which comprises a encrypted encryption key and a transmission unit for transmitting the file encrypted by the file encryption unit. Means, an encryption key decryption means for decrypting the encrypted encryption key received from the transmission source using the secret key, and an encryption key decrypted by the encryption key decryption means. And a file decryption means for decrypting the encrypted file received from the transmission source, the file transfer system using an information recording business card. 3. The file transfer system using an information recording business card according to claim 2, wherein the sender's encryption key creating means creates the encryption key at random for each transmission. 4. The information recording unit of the information recording business card further stores address information of a business card owner, and the reading means of the transmission source is configured to read the address information together with the public key, and The transmitting means is configured to transmit the encryption key encrypted by the encryption key encryption means and the file encrypted by the file encryption means to the read address. A file transfer system using the information recording business card according to claim 2 or 3.