TW201942783A - Confidential signature method and notarization method for one-origin-multiple-copies document to use a private key corresponding to any one of the public keys to decrypt the corresponding variable document key ciphertext to acquire the variable document key - Google Patents

Abstract

A confidential signature method for a one-origin-multiple-copies document is applicable to transmission of an encrypted document among n electronic devices, and mainly comprises loading the data packets transmitted from a previous electronic device, wherein the data packets include the encrypted document and n variable document key ciphertexts. The encrypted document includes the digital information that is decryptable by a variable document key. The variable document key ciphertexts are generated by encrypting the variable document key with n public keys, one of the public key is from a first electronic device. Then, a private key corresponding to any one of the public keys is used to decrypt the corresponding variable document key ciphertext to acquire the variable document key. Then the variable document key is used to decrypt the encrypted document to obtain the digital information of the encrypted document. As a result, only a user who makes the setting could use the private key to acquire the variable document key for decrypting the encrypted document, this enables the protection of privacy and security, and also allows the encrypted document to be a completely identical document transmitted or duplicated among multiple persons, while a user who does not make the setting, even acquiring one copy, cannot proceed with encryption, thereby easing the document keeping and circulation.

Description

Confidential signature method and notarization method for multiple documents

The present invention relates to a method for confidentially signing a document, and more particularly to a method for confidentially signing and notarizing multiple documents.

With the advancement of technology and the popularization of the Internet, digital information is not only easily copied and transmitted, but also the security of data is seriously threatened. Therefore, the encryption technology of digital information occupies a very important position in the information industry, and has been valued by various countries.

"Encryption algorithms" are mainly divided into symmetric encryption algorithms and asymmetric encryption algorithms, of which:

Symmetric encryption algorithm: The encryption key is the same as the decryption key. Only those who have the same key as the sender can decrypt the encrypted ciphertext data. However, the transmission process of the key of the symmetric encryption algorithm must be absolutely secure, so the transmission channel of the key must not be the same as the transmission channel of the ciphertext (such as the network) without encryption. Otherwise, the attacker only needs to Stealing keys and ciphertext during transmission, plus public algorithms in itself, makes encryption a meaningless task.

Asymmetric encryption algorithm: Encrypting the changed key ciphertext is different from decrypting the changed key ciphertext, one of which can be disclosed to others is called a "public key", and the other one that must be kept by itself and not public is called "private." "Key", because it avoids the trouble of transferring the key, so even if intercepted midway, the content of the ciphertext cannot be revealed, which can be said to solve the long-standing problem of symmetric encryption. However, each ciphertext or a copy of the ciphertext can only be decrypted by a specific person, and the ciphertext cannot be transmitted between multiple persons, thus forming an obstacle in use.

Therefore, the main object of the present invention is to provide a method for confidentially signing multiple documents in one or more types, which can ensure privacy and security, and that encrypted documents can be transmitted between multiple persons.

Another object of the present invention is to provide a notarization method for multiple documents that can be used for notarization of non-repudiation and unmodifiable content.

Therefore, the method for confidentially signing multiple documents of the present invention is suitable for transmitting an encrypted document between a transmitting end and at least one receiving end, and the receiving end implements the following steps through an application program: Step a: Loading a data packet, The data packet includes the encrypted file and n changed key ciphertexts, the encrypted file has digital information that can be decrypted by a changed key, and the changed key ciphertexts are encrypted by the n public keys respectively. The result is n≥2, and one of the public keys comes from the first electronic device. Step b: Decrypt the modified key ciphertext encrypted by the public key with a private key corresponding to one of the public keys in step a to obtain the changed key. Step c: Decrypt the encrypted file with the changed key obtained in step b to obtain digital information of the encrypted file.

A notarization method for multiple documents is performed by a notarization device through an application program: Step y1: Receive a data packet; Step y2: Encrypt the data packet of step y1 with a notarized public key and generate a notarized cipher text Step y3: generating a notarized packet including the data packet of step y1 and the notarized cipher text of step y2; and step y4: decrypting the notarized packet with a notarized private key corresponding to the notarized public key to obtain the aforementioned data packet.

The main effect of the present invention is that only the set user can obtain the changed key for decrypting the encrypted file with the personal private key. Not only can it ensure privacy and security, but the encrypted file can be exactly the same. It is transmitted or copied between people, and the encrypted file is difficult to decrypt even if it is obtained by a non-set user, and it is easy to save and circulate, thereby improving the convenience, practicality and greatly reducing the cost of management.

Another effect of the present invention is that the content of the data packet is notarized and cannot be modified without knowing the content of the data packet.

Referring to FIG. 1, a first embodiment of a method for securely signing multiple documents in accordance with the present invention is suitable for transmitting and receiving encrypted files 21 (see FIG. 2) among n electronic devices, of which the mth electronic device Is an electronic device currently being operated. Such electronic devices may be computers, personal digital assistants, tablets, smartphones, etc. The encrypted file 21 may be a contract, a declaration, a certificate, a will, etc. For the convenience of description below, the number of these electronic devices 1a, 1b, and 1c is 3, that is, n = 3, and can also be 2, or 4, 5, 6, 7, 8, 9, 10, or more than 10, when not This is the limit.

Referring to FIG. 2, FIG. 3, and FIG. 4, the electronic devices 1a, 1b, and 1c belong to the first user, the second user, and the third user, respectively, and each holds a public key PublicKey1, PublicKey2, and PublicKey3 for encryption And private keys PrivateKey1, PrivateKey1, PrivateKey3 corresponding to the aforementioned public keys PublicKey1, PublicKey2, PublicKey3 and used for decryption.

In this first embodiment, the first electronic device 1a is the sending end that initiates the signature for the encrypted file 21, the second electronic device 1b is the receiving end, and at the same time, the encrypted file 21 is also transmitted to the third electronic device The sending end of 1c is the receiving end of the third electronic device 1c, and it is also the sending end of the encrypted file 21 returned to the first electronic device 1a and the second electronic device 1b. The electronic devices 1a, 1b, and 1c respectively implement the following steps through an application program:

[Transmitting end]: The first electronic device 1a, please refer to FIG. 5 and FIGS. 2 and 3 below.

Step 31: Combine the signature message Sig1 of the first user in the digital information of the encrypted file 21.

The digital information of the encrypted file 21 also has a signature flow message SigFlow. The signature flow message SigFlow is used to set the position of one of the input signature messages in the encrypted file 21, the signer ’s account number, the signer ’s identity type, the signer ’s identity verification related information, and the time allowed for the signer to sign Intervals (for example, 0 minutes and 0 seconds on February 1, 2018 to 0 minutes and 0 seconds on February 3, 2018), geographic intervals that allow signers to sign (e.g., set geographic intervals with GPS coordinates), and allow signers The signed device code (such as the IMEI code of the electronic device), the signing sequence of the signer, etc., enables the user participating in the signature to control the person, event, time, place, property and signature that can perform the signature according to the above-mentioned signature flow message SigFlow Sequential process to improve security.

Step 32: Using a symmetric encryption algorithm, generate a variable key DocKey1.

Step 33: Encrypt the modified key DocKey1 with the public key PublicKey1 of the first electronic device 1a and the public key PublicKey2 of the second electronic device 1b, and generate two modified key ciphertexts eDocKey1 and eDocKey2.

Step 34: The encrypted file 21 in step 31 is encrypted with the changed key DocKey1.

Step 35: Combine the encrypted file 21 in step 34 with the two changed key ciphertexts eDocKey1 and eDocKey2 into a data packet 2.

Step 36: Output the data packet 2.

[Receiving end]: The second electronic device 1b, please refer to FIG. 6 and FIGS. 2 to 4 below.

Step 41: Load the data packet 2 transmitted by the previous electronic device 1a. Since the previous electronic device is the electronic device 1a, the data packet 2 includes the encrypted file 21, and two changed key ciphertexts eDocKey1 and eDocKey2.

Step 42: The private key PrivateKey2 is used to decrypt the changed key ciphertext eDocKey2 encrypted by the public key PublicKey2 to obtain the changed key DocKey1.

Step 43: Decrypt the encrypted file 21 with the modified key DocKey1 obtained in step 42 to obtain digital information of the encrypted file 21.

Step 44: Combine the signature information Sig2 of the second user in the digital information of the encrypted file 21.

Step 45: Using a symmetric encryption algorithm, generate another variable key DocKey2.

Step 46: The encrypted file 21 in step 44 is encrypted with the modified key DocKey2 in step 45.

Step 47: It is determined whether a next electronic device 1c needs to be signed according to a selected signal M. If yes, go to step 48. If no, go to step 50.

It is worth noting that the aforementioned selected signal M comes from a signal triggered when the user uses the second electronic device 1b and selects the next signing user through the application, or the first user (the first signer) creates a document At the time, according to the set signature flow message SigFlow, each signing item corresponding to a different user (different document signer) has been set in advance, which is triggered when each user (each signer) completes signing.

Step 48: The public key PublicKey1 of the first electronic device 1a ~ the public key of the m electronic device that has received the data packet 2 and the public key of the next electronic device are used to encrypt the changed key DocKey2 of step 45 to generate m + 1 change key ciphertext. Among them, m is an electronic device currently used as a receiving end, and n ≧ 2, and m ≦ n.

Because the current electronic device as the receiving end is the second electronic device 1b, so m = 2, the electronic device that has received the receipt packet includes the first electronic device 1a and the second electronic device 1b. In this implementation, In the example, n = 3, so the public key of the next electronic device is the public key PublicKey3 of the third electronic device 1c, which will be the same as the public key of the first electronic device 1a, PublicKey1, and the public key of the second electronic device 1b. After the public key 2 encrypts the modified key DocKey2 in step 45, three modified key ciphertexts eDocKey1, eDocKey2, and eDocKey3 are generated.

Step 49: Output the data packet 2 including the encrypted file 21 of step 46 and the changed key cipher text eDocKey1, eDocKey2, and eDocKey3 of step 48 to the next electronic device 1c.

Step 50: Encrypt the modified keys DocKey2 in step 45 with the public keys of the n electronic devices to generate n modified key ciphertexts.

Step 51: Output the data packet 2 including the encrypted file 21 of step 46 and the changed key cipher text eDocKey1 and eDocKey2 of step 50 to the aforementioned first electronic device 1a to the m-1 electronic device.

In this embodiment, n = 3. For the second electronic device 1b, there is also the next electronic device 1c. Therefore, steps 50 and 51 are not established, and details are not described herein again.

[Receiving end]: The third electronic device 1c, please refer to FIG. 6 and FIGS. 2 to 4 below.

The third electronic device 1c will repeat steps 41 to 51. Of course, if m = 4, 5, 6, 7, 8, 9, 10, or more, steps 41 to 51 will also be repeated. In order to explain this embodiment more clearly, the following steps for the third electronic device 1c are further described as follows:

Step 41: Load the data packet 2 of the previous electronic device 1b. Since the previous electronic device is the electronic device 1b, the data packet 2 includes the encrypted file 21 and the three key ciphertexts eDocKey1, eDocKey2, and eDocKey3.

Step 42: Use the private key PrivateKey3 to decrypt the changed key ciphertext eDocKey3 encrypted by the public key PublicKey3, and obtain the changed key DocKey2.

Step 43: Decrypt the encrypted file 21 with the modified key DocKey2 obtained in step 42 to obtain digital information of the encrypted file 21.

Step 44: Combine the signature information Sig3 of the third user in the digital information of the encrypted file 21.

Step 45: Using a symmetric encryption algorithm, generate another variable key DocKey3.

Step 46: The encrypted file 21 in step 44 is encrypted with the modified key DocKey3 in step 45.

Step 47: Determine whether to transmit the next electronic device according to the selected signal M. If yes, go to step 47. If no, go to step 50.

Step 48: The public key PublicKey1 of the first electronic device 1a ~ the public key of the m electronic device that has received the data packet 2 and the public key of the next electronic device are used to encrypt the changed key DocKey2 of step 45 to generate m + 1 change key ciphertext.

Step 49: Output the data packet 2 including the encrypted file 21 of step 46 and the changed key cipher text eDocKey1, eDocKey2, and eDocKey3 of step 48 to the next electronic device.

In this embodiment, n = 3. For the third electronic device 1c, there is no next electronic device 1. Therefore, steps 48 and 49 are not established, and details are not described herein again.

Step 50: Encrypt the modified keys DocKey2 in step 45 with the public keys of the n electronic devices to generate n modified key ciphertexts.

Since n = 3 and the third electronic device 1c is currently loaded with the data packet 2, m = n = 3, so in step 50, the public key 3 of the third electronic device 1c will be used, and The public key PublicKey1 of the first electronic device 1a and the public key PublicKey2 of the second electronic device 1b encrypt the changed key Dockey3 in step 45, and then generate three changed key ciphertexts eDocKey1, eDocKey2, and eDocKey3.

Step 51: Output the data packet 2 including the encrypted file 21 of step 46 and the changed key cipher text eDocKey1, eDocKey2, and eDocKey3 of step 50 to the aforementioned first electronic device 1a to the m-1th electronic device.

Since n = 3 and the third electronic device 1c is currently loading the data packet 2, m = n = 3, so in step 51, the data of the changed key ciphertext eDocKey1, eDocKey2, and eDocKey3 will be output. The packet 2 is for the first electronic device 1a to the second electronic device 1b.

As a result, only the first electronic device 1a, the second electronic device 1b, and the third electronic device 1c can decrypt the changed key ciphertext eDocKey1, eDocKey2, and eDocKey3 with the private keys PrivateKey1, PrivateKey2, and PrivateKey3, respectively. DocKey3, while decrypting the digital information in the encrypted file 21 at the same time.

According to the foregoing, the data packets 2 are sequentially transmitted between the first electronic device 1a, the second electronic device 1b, and the third electronic device 1c, so as to achieve the purpose of continuous and sequential signature.

In addition, it is worth noting that after the scheduled user completes the continuous and sequential signing process, the first electronic device 1a, the second electronic device 1b, and the third electronic device 1c only need to repeat steps 41 to 43, and then Obtain digital information of encrypted file 21.

Referring to FIG. 7 and FIG. 8 to FIG. 11, a second embodiment of a method for confidentially signing multiple documents in accordance with the present invention is shown.

In this second embodiment, it is also suitable for transmitting and receiving encrypted files 21 among n electronic devices, where the m-th electronic device is an electronic device currently being operated. The following also takes n = 3 as an example. The electronic devices 1a, 1b, and 1c belong to the first user, the second user, and the third user, respectively, and each holds a public key used for encryption, PublicKey1, PublicKey2, and PublicKey3. , And private keys PrivateKey1, PrivateKey2, PrivateKey3 corresponding to the aforementioned public keys PublicKey1, PublicKey2, PublicKey3 and used for decryption.

The first electronic device 1a is the sender that initiates the signature for the encrypted file 21. The second electronic device 1b and the third electronic device 1c are the receivers. At the same time, the encrypted file 21 is also transmitted to the first electronic device. The sending end of 1a. The electronic devices 1a, 1b, and 1c respectively implement the following steps through an application program:

[Receiving end]: Since the second electronic device 1b to the mth electronic device have m = n = 3, the second electronic device 1b and the third electronic device 1c are the receiving ends, respectively. 12, and Figures 9 and 10.

Step 61: Load the data packet 2. The data packet 2 includes the encrypted file 21, and three changed key cipher texts eDocKey1.1, eDocKey1.2, and eDocKey1.3. The encrypted file 21 has digital information that can be decrypted by a variable key DocKey1. The variable key cipher texts eDocKey1.1, eDocKey1.2, and eDocKey1.3 are respectively encrypted by three public keys PublicKey1, PublicKey2, and PublicKey3. The key DocKey1 (see Figure 8) is generated.

Step 62: Use the private key PrivateKey2 (PrivateKey3) to decrypt the ciphertext eDocKey1.2 (eDocKey1.3) encrypted by the public key PublicKey2 (PublicKey3), and obtain the DocKey1 (Figure 8) .

Step 63: Decrypt the encrypted file 21 with the modified key DocKey1 (see FIG. 8) obtained in step 62, and obtain the digital information of the encrypted file 21.

Step 64: Combine the signature information Sig2 (Sig3) of the second user (third user) in the digital information of the encrypted file 21.

Step 65: Using a symmetric encryption algorithm, generate another change key DocKey2.1 (DocKey2.2).

Step 66: Use the public key PublicKey1 of the first electronic device 1a and the public key of the mth electronic device currently serving as the receiving end to encrypt the changed key DocKey2.1 (DocKey2.2) in step 65, and generate 2 changed funds Key ciphertext.

Taking the second electronic device 1b as an example, step 66 will use the public key PublicKey1 (see Figure 8) of the first electronic device 1a and the public key PublicKey2 corresponding to the second electronic device 1b to encrypt the changed key DocKey2 of step 65. 1. Generates two changed key ciphertexts eDocKey2.1.1 and eDocKey2.1.2.

Taking the third electronic device 1c as an example, step 66 will use the public key PublicKey1 (see Figure 8) of the first electronic device 1a and the public key PublicKey3 corresponding to the third electronic device 1c to encrypt the changed key DocKey2 of step 65. 2. Generate two changed key ciphertexts eDocKey2.2.1 and eDocKey2.2.3.

Step 67: Encrypt the encrypted file 21 in step 64 with the modified key DocKey2.1 (DocKey2.2) in step 65.

Step 68: Output the data packet 2.1 (data packet 2.2) including the encrypted file 21 of step 67 and the changed key cipher text eDocKey2.1.1, eDocKey2.1.2 (eDocKey2.2.1, eDocKey2.2.3) of step 66.

[Transmitting end]: The first electronic device 1a, please refer to FIG. 13 and FIGS. 8 and 11 below.

Step 71: Combine the signature information Sig1 of the first user in the digital information of the encrypted file 21.

Step 72: Using a symmetric encryption algorithm, generate a variable key DocKey1 that can be decrypted in step 62.

Step 73: Encrypt the modified keys DocKey1 of step 72 with the public keys of the n electronic devices, and generate n modified key ciphertexts.

Since n = 3, step 73 will use the public key PublicKey1 of the first electronic device 1a, PublicKey2 (see Figure 9) of the second electronic device 1b (see Figure 9), and the third electronic device 1c ( The public key PublicKey3 (see Figure 10) (see Figure 10) encrypts the changed key DocKey1 and generates three changed key ciphertexts eDocKey1.1, eDocKey1.2, and eDocKey1.3.

Step 74: The encrypted file 21 in step 71 is encrypted with the modified key DocKey1 in step 72.

Step 75: Combine the encrypted file 21 of step 74 and the n changed key ciphertexts into n-1 data packets 2.

Since n = 3, and there are 3 changed key ciphertexts eDocKey1.1, eDocKey1.2, and eDocKey1.3, the encrypted file 21 in step 74 will be compared with 3 changed key ciphertexts eDocKey1.1 and eDocKey1.2. , EDocKey1.3 combined into 2 data packets 2.

Step 76: As shown in FIG. 7, the data packets 2 are output to the second electronic device 1b to the m-th electronic device.

Since m = n = 3, step 76 is to output the data packets 2 to the second electronic device 1b and the third electronic device 1c.

Step 77: Referring to FIG. 13 and FIG. 11, load the data packets 2.1 and data packets 2.2 output by the second electronic device 1b to the m-th electronic 1c in step 68.

Step 78: The private key PrivateKey1 of the first electronic device 1a is used to decrypt the data packet 2.1 and data packet 2.2 corresponding to the changed key cipher text eDocKey2.1.1, eDocKey2.2.1 (eDocKey2.2.1, eDocKey2.2.3) in step 77. (See FIG. 9 and FIG. 10), and obtain the modified keys DocKey2.1 and DocKey2.2 in step 65 (see FIG. 9 and FIG. 10).

Step 79: Decrypt the encrypted files 21 with the modified keys DocKey2.1 and DocKey2.2 (see Figs. 9 and 10) obtained in step 78, and obtain the digital information of the encrypted files 21.

Step 80: Combine all the signature information Sig1 and Sig3 in the digital information of the encrypted file 21 in one of the data packets (take the receipt packet 2.1 as an example in this embodiment), and combine the second electronic device 1b ~ m The encrypted file 21 of the electronic device in step 64 is embedded as an attachment in the aforementioned encrypted file 21 combining all the signature messages Sig1 and Sig3.

Since m = n = 3, step 80 is to embed the encrypted file 21 of the second electronic device 1b to the third electronic device 1c in step 64 as an attachment in the aforementioned encrypted file combining all the signature messages Sig1 and Sig3. 21 in.

Step 81: Generate a final change key DocKey3.

Step 82: Encrypt the modified keys DocKey3 in step 81 with n public keys to generate n modified key ciphertexts. In this embodiment, three public keys PublicKey1, PublicKey2, and PublicKey3 are used to encrypt the modified key DocKey3 in step 81 to generate three modified key ciphertexts eDocKey3.1, eDocKey3.2, and eDocKey3.3.

Step 83: The encrypted file 21 in step 80 is encrypted with the final changed key DocKey3 in step 81.

Step 84: Delete the final change key DocKey3 generated in step 81.

Step 85: Output a final data packet 2 'including the encrypted file 21 of step 83 and the changed key cipher text of step 82 to the aforementioned second electronic device 1b to the m-th electronic device.

Since m = n = 3, step 85 outputs the final data packet 2 'to the second electronic device 1b to the third electronic device 1c.

As a result, only the first electronic device 1a, the second electronic device 1b, and the third electronic device 1c can decrypt the eDocKey3.1, eDocKey3.2, and eDocKey3.3 with the private keys PrivateKey1, PrivateKey2, and PrivateKey3, respectively, to obtain the change money. The key DocKey3 simultaneously decrypts the digital information in the encrypted file 21 at the same time.

According to the foregoing, the data packet 2 is simultaneously transmitted by the first electronic device 1a to the second electronic device 1b and the third electronic device 1c, thereby achieving the purpose of simultaneous signature by multiple persons.

In addition, it is worth noting that after the scheduled user completes the synchronous signing process, the first electronic device 1a, the second electronic device 1b, and the third electronic device 1c need only repeat steps 61 to 63 to obtain encryption. Digital Information for Document 21.

Referring to FIG. 1, FIG. 7, and FIG. 14 and FIG. 15, the notarization method for multiple documents of the present invention uses a notarization device 10 as a tool, and the notarization device 10 belongs to a notary public, and uses public and encrypted Notarized public key PublicKey4, and notarized private key PrivateKey4 corresponding to the aforementioned notarized public key PublicKey4 and used for decryption.

The notary device 10 implements the following steps through an application:.

Step 91: Receive a data packet 2 (2 '). The data packet 2 (2 ') may be the final data packet 2' in step 85 in the second embodiment, or the data packet 2 in step 58 in the first embodiment.

Step 92: The data packet 2 (2 ') is encrypted according to a seal condition and the notarized public key PublicKey4, and a notarized cipher text eNotary is generated.

Step 93: Generate a notarized packet 2 "including the data packet 2 (2 ') of step 91 and the notarized cipher text eNotary of step 92".

At this time, for the notary of the notary device 10, because the encrypted data packet 2 (2 ') cannot be decrypted, the encrypted file 21 can be processed without knowing the content of the encrypted file 21 Notarization and non-modifiable content notarization.

It is worth noting that in step 93, the aforementioned notarized packet 2 "may be transmitted to the electronic device 1a, the second electronic device 1b, and the third electronic device 1c, and the first electronic device 1a and the second electronic device 1b may be retained. , And the first user, the second user, and the third user of the third electronic device 1c will not be able to decrypt the notarized cipher text in the notarized packet 2 because the notarized private key PrivateKey4 corresponding to the notarized public key PublicKey4. eNotary, also achieves non-repudiation and unmodifiability.

Step 94: When the seal condition is released, the notarized cipher text eNotary in the notarized packet 2 "is decrypted with the notarized private key PrivateKey4 corresponding to the notarized public key PublicKey4, and the data packet 2 (2 ') is obtained.

The aforementioned seal conditions can be electronic or manual. The encrypted file 21 is a contract as an example. The electronic seal conditions can be date conditions. For example, the contract was signed on January 1, 2016, and set January 1, 2017. Automatically release the seal condition. Taking the encrypted file 21 as a testament as an example, the manual seal condition may be a human condition. For example, if the testator dies on a date that cannot be expected, the death of the testator will come to an end and the seal condition will be lifted.

Step 95: The data packet 2 (2 ') is transmitted to the aforementioned n electronic devices, in this embodiment, it is transmitted to the first electronic device 1a, the second electronic device 1b, and the third electronic device 1c.

As a result, the first electronic device 1a, the second electronic device 1b, or the third electronic device 1c loaded in the data packet 23 can each use the private key PrivateKey1 (as shown in Figs. 2 and 8) and PrivateKey2 (as shown in the figures). (3, Figure 9), PrivateKey3 (Figure 4, Figure 10) decrypt eDocKey1 (eDocKey3.1), eDocKey2 (eDocKey3.2), eDocKey3 (eDocKey3.3) to obtain the change key DocKey3 (DocKey3), and at the same time decrypt the encrypted file Digital information in 21.

Through the above description, the advantages of the foregoing embodiments can be summarized as follows:

1. The present invention uses the aforementioned special encryption method. Similarly, only the set user can obtain the changed key for decrypting the encrypted file 21 with the personal private key. Therefore, even if the encrypted file 21 is intercepted in the middle, or by a non-set user After obtaining a copy, the content of the encrypted file 21 cannot be decrypted, and it is easy to save and circulate. It is important to combine the method of encrypting and decrypting the encrypted file 21 with a change key to make the encrypted file 21 sequentially or through data packets. Simultaneous transmission or copying to multiple people, to achieve the purpose of continuous and sequential signing, or the purpose of simultaneous signing by multiple people, greatly reducing the cost of management.

2. Furthermore, the present invention can cooperate with the aforementioned notarization method, so that the notary public can notarize and deny the content of the encrypted file 21 without knowing the content of the encrypted file 21, and can also make the first The user, the second user, and the third user cannot decrypt the notarized packet 2 ", which also achieves non-repudiation and non-modifiability, ensuring privacy and security.

3. In addition, since the present invention can limit the users to be decrypted, the set user may not be the signatory, but it can also be a specific person who is authorized to operate the file with specific permissions (such as only being able to read or export). The present invention can also be applied to the sale and distribution of e-books, whereby only users who pay or meet the conditions can obtain the changed key for decrypting the encrypted file 21 with their personal private keys, and other illegal users can obtain data packets 23. It is also impossible to open the encrypted file 21. Of course, the encrypted file 21 can be protected from information content extraction through the permission setting, or the user is prohibited from changing the changed key and the changed key ciphertext, thereby improving the security of the encrypted file 21.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, any simple equivalent changes and modifications made according to the scope of the patent application and the contents of the patent specification of the present invention are still Within the scope of the invention patent.

1a ~ 1c‧‧‧Electronic device

10‧‧‧Notary device

2, 2`‧‧‧ Data Packet

2.1‧‧‧Data Packet

2.2‧‧‧Data Packet

21‧‧‧ encrypted file

2``‧‧‧Notarized packet

31 ~ 36‧‧‧step flow

41 ~ 52‧‧‧step flow

61 ~ 68‧‧‧step flow

71 ~ 85‧‧‧step flow

91 ~ 95‧‧‧step flow

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a schematic diagram illustrating a first embodiment of a method for confidentially signing multiple documents of the present invention; FIG. 2 is a schematic diagram illustrating the encryption of the encrypted file by the first electronic device in the first embodiment and the data packet output therefrom; FIG. 3 is a schematic diagram illustrating the encryption of the second electronic device in the first embodiment The file is encrypted, and the data packet it outputs; Figure 4 is a schematic diagram illustrating the encryption of the encrypted file by the third electronic device in the first embodiment, and the data packet that it outputs; Figure 5 is the first embodiment FIG. 6 is a flowchart of a receiving end in the first embodiment; FIG. 7 is a schematic diagram illustrating a second embodiment of a method for confidentially signing multiple documents in accordance with the present invention; FIG. 8 is a schematic diagram illustrating the first electronic device in the second embodiment to encrypt the encrypted file and the data packet output therefrom; FIG. 9 is a schematic diagram illustrating the second embodiment in the second embodiment The electronic device encrypts the encrypted file and its output data packet; FIG. 10 is a schematic diagram illustrating the third electronic device encrypts the encrypted file and its output data packet in the second embodiment; FIG. 11 is a A schematic diagram illustrating that the first electronic device in the second embodiment encrypts the encrypted file again; FIG. 12 is a flowchart of a receiving end in the second embodiment; FIG. 13 is a flowchart of a transmitting end in the second embodiment A flowchart; FIG. 14 is a schematic diagram of the notary method of the foregoing embodiment, illustrating a notary device encrypting the aforementioned data packet and a notary packet generated by it; and FIG. 15 is a flowchart of the notary method of the foregoing embodiment.

Claims (13)

A method for confidentially signing multiple documents is suitable for transmitting and receiving encrypted documents between n electronic devices. Each electronic device implements the following steps through an application program: Step a: Load the data transmitted by the previous electronic device. Packet, the data packet includes the encrypted file and two or more changed key ciphertexts, the encrypted file has digital information that can be decrypted by a changed key, and the changed key ciphertexts are composed of two or more public keys Generate the encrypted encryption key separately, and one of the public keys comes from the first electronic device; Step b: Decrypt the encrypted ciphertext of the modified key encrypted by the public key with a private key corresponding to one of the public keys in step a To obtain the changed key; step c: decrypt the encrypted file with the changed key obtained in step b to obtain digital information of the encrypted file. As described in claim 1, each electronic device serving as a receiving end, through the application, further includes step c after step c: combining the signature information with the digits of the encrypted file In the information; Step e: Generate another changed key; Step f: Encrypt the encrypted file of step d with the changed key of step e; Step g: Determine whether to transmit the next electronic device, and if so, go to step h-1, If not, go to step h-3; Step h-1: Encrypt the public key of the first electronic device to the public key of the mth electronic device that has received the data packet and the public key of the next electronic device. Change the key to generate m + 1 ciphertext of the changed key, where m is the electronic device currently used as the receiving end, and n≥2, m ≦ n; Step h-2: Output the encrypted file including step f and The data packet of the changed key ciphertext in step h-1 is sent to the next electronic device; step h-3: the public key of the n electronic devices that have received the data packet is used to encrypt the changed keys in step e to generate n changes Key ciphertext; and step h-4: the output includes step f Secret file 21 and h-3 step changes the key ciphertext data packets to said first electronic device 1a ~ 1 m-1 of the electronic device. The method for confidentially signing multiple documents as described in claim 2, wherein the data packet received by the second electronic device to the mth electronic device in step a is the m-1th electronic device in step h-2 output. The method for confidentially signing multiple copies of a document as described in claim 1, wherein the digital information of the encrypted document also has a signature flow message, and the signature flow message is used to set a signature field of one of the signature information input to the encryption. Location in the file, signer's account number, signer's identity type, signer's identity verification related information, time interval allowed for signer to sign, geographic interval allowed for signer to sign, device code that allowed signer to sign, signature At least one of them must be in order. The method for confidentially signing multiple documents as described in claim 2, wherein the data packets received by the second electronic device to the m-th electronic device in step a are all from the first electronic device, and m = n. According to the method for confidentially signing multiple copies of a document as described in claim 5, the second electronic device to the m-th electronic device respectively through the application also include step i after step c: combining the signature message with the encryption In the digital information of the file; Step j: Generate another change key; Step k: Encrypt the change key of step j with the public key corresponding to the private key of the first electronic device and the private key of the m electronic device Key and generate 2 modified key ciphertexts; Step l: Encrypt the encrypted file of Step h with the changed key of Step j; Step o: Output the data including the encrypted file of Step l and the changed key ciphertext of Step k Packet. As described in claim 6, the first electronic device further includes step p after step o: loading the second electronic device to the m-th electronic output in step o The data packets; Step q: Decrypt the corresponding changed key ciphertext in step o with the private key of the first electronic device to obtain the changed key in Step j; Step r: Obtain in Step q The encrypted key is used to decrypt the encrypted files and obtain the digital information of the encrypted files. As described in claim 7, the first electronic device further includes a step s after step r: combining all the signature information into the digital information of one of the encrypted files; step t : Generate a final modified key; Step u: Encrypt the modified key of Step t with n public keys to generate n Variable key ciphertexts; Step v: Encrypt the encryption of Step s with the final Changed key of Step t File; and step w: output the final data packet including the encrypted file of step v and the changed key ciphertext of step u to the aforementioned second electronic device to the m-th electronic device. The method for confidentially signing multiple documents as described in claim 8, wherein the encrypted file of step s is further combined with other encrypted files from step r and embedded as an attachment. The method for confidentially signing a plurality of documents as described in claim 8, further comprising step x after step v and before step w: deleting the final change key generated in step t. A notarization method for multiple documents as described in claim 8, which implements the following steps by an notary device through an application: Step y1: Receive the final data packet of step w; Step y2: Encrypt with a notarized public key The final data packet of step y1 and generates a notarized ciphertext; step y3: generating a final data packet including step y1 and the notarized cipher text of step y2; and step y4: to correspond to the notarized public key A notarized private key is used to decrypt the notarized packet to obtain the final data packet of step w. A notarization method for multiple documents as described in claim 2, by a notary device through an application program to achieve the following steps: step y1: receiving the data packet of step h; step y2: encrypting step y1 with a notarized public key Step y3: generate a data packet including step y1 and step y2 of a notarized cipher text; and step y4: decrypt a notarized private key corresponding to the notarized public key This notarized packet obtains a data packet including the changed key ciphertext of step h-1. The notarization method of multiple documents as described in claim 11 or 12, wherein step y2 further encrypts the data packet according to a seal condition, and in step y4, when the seal condition is removed, the response The notarized private key of the notarized public key decrypts the notarized packet to obtain a data packet including the changed key ciphertext of step h-1.