TW434516B - Method for batch authentication of multiple digital certificates and method for identification of illegal digital certificates - Google Patents

Abstract

The present invention relates to a method for batch authentication of multiple digital certificates anda method for identification of illegal digital certificates. The method for authentication of multiple digital certificates comprises: providing a process unit to calculate the product of all the public key hash values and the product of all the public key certificates; using the signer's public key to decrypt the product of all the public key certificates; and, by comparing the decryption result with the product of all public key hash values, confirming the legality of each public key certificate. Then, the method for identification of illegal digital certificates should be applied if any illegal public key certificate is found, which comprises: using a process unit to divide all the public key certificates into several subgroups and the foregoing authentication method is applied to check each subgroup individually; using the process unit again to carry out the same authentication procedure on subgroup found to have any illegal public key certificate until only one public key certificate remains in each subgroup.

Description

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V. Description of the invention (1) The present invention relates to a cryptographic communication, and in particular to a method for batch verification of multiple digital vouchers and identification of illegal digital vouchers, which can greatly improve the efficiency of simultaneously verifying multiple digital vouchers, and Identify the illegal digital credentials. With the combination of computer and communication technology, the collection and transmission of information has increased dramatically in terms of speed and quantity. Diversified applications have made electronic transmission replace traditional paper-based communication methods. This result makes the use of information even higher ’, but it also makes the information vulnerable to malicious attacks by illegal or unauthorized persons. Therefore, how to combine information security technology with electronic communication systems to protect the privacy and authenticity of information 'and not be subject to passive eavesdropping or active tampering becomes a top priority. DESCData Encryption Standard) is the first publicly available cryptographic algorithm endorsed by the US government. It is a single-key cryptosystem. The so-called single-key cryptosystem is that the records used for encryption and decryption can be easily deduced from each other, that is, with the encrypted records, the decryption keys can be easily obtained, and vice versa. In 1 976, two scholars, Diffie and Hellamn, proposed the concept of the so-called "public key" cryptosystem to solve the problem of secret key exchange in a single-key cryptosystem. In the key cryptosystem, each key used for encryption has a corresponding decryption key. This pair of completely different keys has an inseparable relationship, but you want

Page 4 V. Description of the invention (2) Eight In this public record password system, the encrypted golden picture of each member must be opened, everyone knows. In this way, anyone who uses the recipient ’s public golden wheel to encrypt the confidential file can securely send the encrypted confidential file to the receiver through the user ’s secure channel. Since only the legitimate receiver will have the decryption key corresponding to the encryption key, only the recipients who are able to decrypt the encrypted secret file will be able to solve it. & Lost Mimar system has a very unique feature, which is the so-called digital signature (Digital Signature). Digital signatures, like traditional autographs, can be used to identify the author of the signature. A digital signature is an act of signing an electronic document, and the result of the signature can provide authentication and non-repudiation. To sign an electronic document, the sender must first enter the electronic document into a so-called one-way hash function to obtain a message digest or hash value. To be safe, the one-way hash function must have two characteristics: it is very easy to get the message digest from the input message, and it is very difficult to push back the input message from the message digest. Once the message digest is obtained, the sender can use the undisclosed decryption balance to encrypt the message digest, and the result of this encryption is the so-called digital signature. The sender can then attach the digital signature to the original electronic file and send it to the receiver for later verification. The receiver can decrypt the digital signature by using the encrypted Jinyu disclosed by the sender to restore the message digest when the signature is signed. On the other hand, the receiver can also enter the received electronic file into a one-way hash function to obtain a message digest, and return the message digest with a digital signature.

Page 5 r A 3 13¾ 5. Description of the invention (3) The original message summary is compared. If they are the same, it means that the electronic file has not been tampered with. At present, there are two well-known public cryptosystems that can provide encryption and signatures at the same time. They are respectively a security-based RS A system (US Patent No. 4 '4 05' 829) and a security-based discrete logarithm. ElGamal system in question. Recently, the Elliptic Curve Cryptosystem (ECC) based security has also been noticed and considered by IEEE PI 363 as one of the standards for cryptographic systems. In fact, the security of elliptic curve-based cryptosystems has many of the same characteristics as the ElGamal system of security based on solving discrete logarithms. The RSA system has been adopted by organizations such as VISA and MasterCard as the Standard for Secure Electronic Transaction (SETTM) to ensure the security of electronic credit transactions and payment information on the Internet. In public cryptosystems, public records must be generated by some trusted certificate authority (CA), and the public input certificate is placed in the directory by the certificate authority or user. Each publicly recorded certificate is signed by the certificate authority with the user's public key using its own private key. The purpose of the public key certificate is to help other users verify the legitimacy of the public key owner. ITU-T recommends using X.509 as part of the X.500 directory retrieval service. X.509 provides authentication services for X.500 directory search services. However, 'the standard does not prescribe those specific algorithms. In fact, X.509 has been used in a variety of situations. For example, the certificate format of χ.509 has been adopted by S / MIME, IP Security, SSL / TLS and SETTM.

4345 ΐ Sf V. Description of the invention (4) Unfortunately, 'verifying digital credentials is a very time-consuming task, especially when verifying digital credentials of the ElGamal type. For example, it is generally recommended that ElGamal-type certificates need at least two 512-bit signatures to be secure. However, such a large voucher requires a two-bit Modular Exponentiation operation, so it is indeed a time-consuming task to verify multiple digital vouchers in batches. In view of this, the main purpose of the present invention is to propose a method for batch verification of multiple digital certificates and identification of illegal digital certificates, which can efficiently verify multiple public key certificates from the same certificate authority (signator), and Illegal digital credentials were pointed out. 〃 To achieve the above and other objectives, the present invention proposes a method for batch verification of multiple digital certificates, which is used to verify multiple public key certificates from the same signer in an insecure communication channel in order to confirm all public keys The legitimacy of the credentials. The steps of this verification method include: providing a processing unit; and using the processing unit to calculate the hash value product of the public key and the f product of the public record vouchers, and using the public key of the signatory The product of the public key certificates is decrypted, and the product of the decryption result and the hash value of the public keys is compared, and the legitimacy of all public key certificates is met. In this verification method, the public key certificates can be obtained by RSA digital signature method or E1Gafflal digital signature method. The processing unit may be composed of a data processing unit or a communication gateway. In addition, the present invention also provides a method for identifying illegal digital certificates to point out illegal ones in multiple public key certificates of the same signer. Public key certificate. The steps of this identification method include: (a) providing a processing unit;

434516J V. Description of the invention C5) (b) Use this processing unit to divide all public key certificates into a plurality of subgroups, and verify the visibility of each subgroup separately; and (c) Use this processing unit to have illegal public input Sub-groups of vouchers repeat step (b) until there is only one round of vouchers left in each sub-group. In this authentication method, the verification method of the subgroups is to use the processing unit to calculate the product of the hash value of all public records in the subgroup and the product of the public certificate, and use the public records of the signatory Decrypt the product of the public input vouchers to verify the legitimacy of all public input vouchers in the subgroup. In addition, these public certificate can be obtained by A digital signature method or E 1 G a m a 1 digital signature method. The processing unit may be composed of a data processing unit or a communication gateway processor. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings to make a detailed description as follows: Description of the drawings FIG. 1 is the present invention Flow chart of using a data processing unit or a communication gateway processor to verify multiple RSA digital certificates signed by the same private ship; Figure 2 is a flowchart of the present invention using a data processing unit or a communication gateway processor to verify the same § ^ by the same The flowchart of multiple E 1Gama 1 digital vouchers signed by the private M # Jing, Figure 3 is two ElGam al type digital signatures applied to the verification method of the present invention and their corresponding verification formulas; and FIG. 4 is a flowchart of identifying illegal digital signatures from eight digital signatures by using the method of the present invention. Preferred embodiment

4345t6J V. Description of the invention (6) --------------- Verification of digital certificates requires a lot of calculations, so when verifying multiple digital certificates at the same time, the time consumed in calculation is also Very impressive. In view of this, the present invention proposes a method for verifying multiple digital vouchers and identifying illegal digital vouchers, which can greatly reduce the amount of calculation required during verification, and is therefore very suitable for e-commerce. For example, according to the method ′ of the present invention, multiple certificates signed by the same certificate authority or multiple messages signed by the same payment agency require only one verification action to complete the verification of all certificates. Unlike ordinary verification methods, which slowly verify digital certificates one at a time, the present invention verifies digital certificates generated by the same private key in a systematic manner. Regardless of whether the digital certificate is a digital certificate obtained by the RSA digital signature method or the ElGamal digital signature method, the present invention can verify all digital certificates at the same time, and it * time is the same as the verification time of a digital certificate. This feature makes the present invention very suitable for situations where a large number of digital credentials need to be verified. In the method for verifying multiple digital certificates of the present invention, a data processing unit (DPU) or a communication gateway processor (Communication Gateway Processor) is used to process one or more communication channels through an insecure communication channel such as the Internet. The message transmitted between two entities plays the role of receiving and verifying a large number of digital certificates at the same time. Therefore, the data processing unit (DPU) or communication gateway processor (Communication Gateway Processor) is used to check the content of the public key certificate and divide all public input certificates into several subgroups. Among them, the public belonging to the same subgroup Key certificates are generated using the same private key. For each subgroup, data processing unit (DPU) or communication gateway

4 345 t6.i 5. Description of the invention (7) " — The Communication Gateway Processor calculates a hash value for the public machine information of all digital certificates. In this example, 'if the digital voucher is generated using the rSA digital signature method, the data processing unit or communication channel processor can use the modulus η to find the product of all hash values, where η is the product of two large prime numbers. At the same time, the data processing unit (DPU) or the communication channel processor (common gateway processor) will also calculate the product of all digital signatures in the same subgroup under the module n. Then, the signer's public key is used to decrypt the product of these digital signatures under the mode η to verify the legitimacy of all public key certificates until the receipt of the certificate is public with the key. Multiplying by the value, some miscellaneous. All that is combined with law and fruit is a secret testimony. If the public information contained in the key is different, then the stored data is processed and the product summary of the Gateway Chapter is summed together. If the solution is legal, a large number of public certificates are verified. Large prime number p recognized by members of the group. Then, the unit (DPU) or communication gateway processor (common processor) calculates all partial signatures in the module (m0 (hilo) p), and calculates two separate and partial modules in the module p-1. The total value of the signature and customs clearance. Finally, the public key of the signer is used to decrypt the product of these two and the sf calculated beforehand. The secret result passes the signature verification, then all the digital certificates received. Because the present invention only needs a decryption action, the time required to verify the key message can be significantly reduced. Conversely, if the comparison fails, it means that there are illegal digital credentials mixed in the received

Page 10 4345161, V. Description of the invention ⑻-Digital S login. At this time, in order to identify illegal digital credentials, we can divide the received digital credentials into two subgroups' and verify the credentials of the two subgroups individually using the aforementioned verification method. If the verification fails, it means that illegal digital credentials exist in this subgroup. As a result, as long as the grouping and verification work is repeated, illegal digital credentials can be identified. In the first figure, 'If the communication gateway processor needs to verify t public key information called' m2 'mt, only the digital signature (represented respectively as Si, s2, ..., st)' is based on the RSA encryption method. Each signatory who wants to generate a digital certificate of rs A must first choose a modulus n = pq, where ρ and q are two secret large prime numbers. Here 'assume that e is the public key of the signatory and d is the corresponding private key, where ed mod (pl) (ql) = 1, and h (m) represents the hash obtained by bringing the message m into a one-way hash function. Value, the message% and its RSA digital signature 5; satisfy the relationship of mod η. The digital signature verification method is to check whether = S / mod η is established. In other words, the receiver brings the received public input message into a one-way hash function 'and compares the obtained hash value with the value decrypted from the digital signature using the public key e. Because the RSA digital signature method has the characteristics of multiplication homomorphism (Mul tipi icative Homomorphism), when the decryption result of all digital signature products is equal to the product of all public key message digests, that is (m) e i.1 RSA Digital signature 3 In this mod η, all public key information ~ 'm2, ..., s2'St of mt are legal. nh (mi) mt of the individual signatures of the public key information in.

434lSt 61 V. Description of the invention (9) The product i-i rood η is called the signature product (Multiplicative Digital

Signature) to facilitate the following discussion. Because the signing of the early product check is only required to use the public record e to perform a decryption operation. Therefore, the present invention facilitates the use of the RSA digital signature method with the characteristic of multiplicative homomorphism, and treats the signature product as a legal signature of t public key information%,%, ..., &. Please refer to FIG. 1. This is a flowchart of verifying multiple rSA digital certificates signed by the same private key using a data processing unit or a communication gateway processor according to the present invention. & a As shown in the figure ’In step 10, the communication gateway processor first calculates the message digests h (mi), h (m2), ..., h (m) of each public key information. Next, in step 12, all the received message digests are multiplied by modulo ^ to obtain h (ni)) h (m2) ... h (mt) m 〇 d η. Similarly, in step 14 ', the communication gateway processor calculates the RSA signature product S! S2 ... St mod η corresponding to all public key information. Finally, in step 16 the signer's public key is used to decrypt the product of the digital signature, and the decryption result is compared with the product of all public key message digests. That is, the communication gateway processor of the receiver t ΐ- checks whether (〇Si) e = Dh (mi) mod η is established. If all digital signatures are legal, the above formula will hold. With this, t RSA digital signatures $ 1, \, ..., st can be efficiently completed within the signature verification time. In addition, the communication gateway processor verifies t public key information calls, m

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4 3451 6 I Jade, description of the invention (ίο)… ’mt ’s ElGamal type signature \, S2 ..... st is another example applicable to the present invention. In a digital signature system of the ElGamal type, the signer must choose a publicly large prime p. For the convenience of explanation, suppose χ is the private key of the signer, and y = αχ mod ρ is its corresponding public key, where α is the original number existing in the finite field GF (p). Then, we can write r in the ElGamal digital signature (Γι, Si) signed for the message call as 卩 = akl mod p, where ki is a secret integer chosen by the signer 'and Si is (H (mi), r ;, X, ki) is a function of parameters.

Harn and Xu scholars listed 18 digital signatures of ElGamal type. From the proof of mathematical theory, as long as the digital signature is generated using the signature formula listed in Figure 3, the verification of t signatures can be done in one battle. In order to facilitate the discussion, suppose that SiZki-rihCmJx mc) d pi, the verification of the signature is to bring the public key message and its corresponding signature to s: him) Verification formula * ν = α y mod ρ . If the product mod p of all digital t signatures is equal to the product of all mod ρ, Πγ t is ί′1 = α > mod ρ, then all public key information mi, m2 '…, watts of mt 1〇311131 The type signature (r) '' (r2 's2), ...' (rt, st) are all legal. Because this verification also only needs to use the public round y for a decryption operation. Therefore, the present invention can use This feature is used to verify the legitimacy of t public key information%, m2, ... 'at the same time. Please refer to Figure 2' This is the data processing unit or communication gateway.

Page 13 V. Description of the invention (11) Flow chart of the processor to verify multiple El Gama 1 digital certificates signed by the same private person. As shown in the figure, in step 20, first calculate all public information Message summary) 1 (%), h (m2), ... 'h (mt). Next, in step 22, the product qr2 ... rt mod p of all partial signatures is calculated. Then, in step 24, we calculate 11) 1 'mC) d P ~ 1 of S2 tiSi mod p-1 and R stone. In step 骡 26, asyR mod p is calculated. In step 28, the communication gateway processor of the tny receiver checks whether = asy mod p holds. If all digital signatures are legal, the above formula will hold. From this, it can be seen that t E 1 Gama 1 type signatures (q, s), (r2, s2), ..., (rt 'st) can also be used to effectively verify the work in one battle. Figure 3 shows the two EiGamal digital signature methods applicable to the present invention and their corresponding verification formulas. Because only one decryption action is required, no matter the user chooses the signature method described in Figure 1 or Figure 2 to generate the public record certificate, the time required to verify the public key message is greatly reduced. If an illegal digital certificate exists in the received many public key certificates, the equal sign of the verification formula in step 16 of FIG. 1 and step 28 of FIG. 2 will not hold. In this case, all the public key certificates can be divided into two subgroups' and each subgroup is verified using the batch verification method described previously. If the test of the verification formula is passed, the credentials of the subgroup are all legitimate, otherwise, there are illegal credentials in the subgroup. therefore

Page 14 43 ^ 5 t 6 § V. Description of the Invention (12) ’As long as the above steps are repeated for subgroups containing illegal credentials until each subgroup contains only one credential, all illegal credentials can be identified. Please refer to FIG. 4 for a flowchart of identifying illegal digital signatures from eight digital signatures using the method of the present invention. As shown in the figure, 'assuming that the communication gateway processor is to verify eight register credentials Si, sa' ..., s8 ', all of which are valid credentials except S5. In step 40, use the method described in Figure i or Figure 2 to verify eight logins at the same time. However, because it contains illegal credentials, it cannot pass step 16 (RSA signature) in Figure 1 or Figure 2 Test of step 28 (ElGamal type signature). In this case, these credentials can be divided into (&, S2, S3, S4) and (S5, SB, S7, S8) two subgroups. In step 42, the subgroup (Si, SZ 'Ss' SO passes the verification, but the subgroup (S5 'S6' S7, S8) that fails the verification must be further divided into equal parts (§5, se) and (S7, S8) Two subgroups. In steps 46 and 46, because S5 is an illegal credential, 8 (Ss, Se) is cut into (Ss) and (se) two subgroups. Finally, in steps 48 and 48, the illegal credentials Sjj are successfully identified. In summary, the method of batch verification of multiple digital credentials and identifying illegal digital credentials of the present invention can be efficiently verified Multiple publicly-documented certificates from the same certificate ((signator)) will point out the illegal digital certificate among them. In addition, the present invention is not only applicable to a certain type of public key cryptosystem but is applicable to any signature system. The elliptic curve signature method drafted by IEEE Pl 363 has similar characteristics to the ElGamal type digital signature, so the present invention can also be applied to the elliptic curve signature method.

AA 隽 表 6 A 8 ^ _ V. Description of the Invention (13) Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art will not depart from the spirit and scope of the present invention. Within the scope, it can be modified and retouched. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

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Claims (1)

¢ 321¾ 1 6 ^ VI. Patent application scope j. A method for batch verification of multiple digital certificates, verifying multiple public key certificates from the same signer in an insecure communication channel in order to confirm the validity of all public key certificates Legitimacy, the steps include: providing a processing unit; and using the processing unit to calculate a product of the hash values of the public keys and a product of the public key certificates' and decrypting the public key certificates using the public key of the signatory The product of 'is compared to the product of the decryption result and the hash value of the public keys', and the legality of all public key certificates is recognized. 2 _ The method for batch verification of multiple digital certificates as described in item 1 of the scope of patent application ', wherein the public key certificates are obtained by the RSA digital signature method. 3 _ — A method for batch verification of multiple digital certificates, verifying multiple public key certificates from the same signer in an insecure communication channel, in order to confirm the legality of all public key certificates, the steps include: providing a Processing unit; and using the processing unit to calculate the hash value of the public keys, the ^ product of all partial signatures: and the sum of the two values related to the partial signature and the hash value, respectively, and 1 If the two sums are signed with all parts, μ v decrypts them. If the decryption result passes the signature verification, all the received key certificates are legal. As described in Item 3 of the Patent Scope, please apply for batch verification of multiple digital certificates. These public key certificates are obtained by the ElGamal digital signature method. π ^ t claims the method of batch verification of multiple digital cards as described in item 1 or 3 of the patent scope ', where the bite is in the process and the processing element is composed of a data processing unit. Page 17 No. 1 6 J. Patent Application Range 6. The method of applying for patent scope 苐 哎 灯 lamp method, in which the batch described in the processing item validates multiple digits 4 7. Identification of illegal public cruises; m-channel processing器 组合。 Composition. Illegal ::: method is used in multiple rounds of vouchers to: (a) provide a voucher for the success of the same-signature, the steps of which include: (b) the use of the processing unit Jiang group, and eight forces # 立 μ ^ f All public key certificates are divided into a plurality of subgroups. Do not verify the authenticity of each subgroup; and repeat + 丄 spear: η processing single 覆 step over subgroups with illegal public key certificates = ) Until there is only one public record credential in each subgroup. Law, 2 claims: the party identifying the illegal public certificate mentioned in item 7 of the patent scope, this public record certificate is obtained by RSA digital signature method, then all eight groups, and the method is to use the processing unit to calculate the child In the group = the product of the two remaining hash values and the product of the public certificate, and use the right of the signature to decrypt the product of the public key certificates, # to verify the legality of all public key certificates in the subgroup Sex. 9 The party identifying the illegal public key certificate as described in item 7 of the scope of the patent application, wherein if these public key certificates are obtained by the digital signature method of £ 1 (^ 11] £ 11, these subgroups The verification method is to use the processing unit to calculate the public ^: hash value 'product of all partial signatures, and two sum values related to partial signatures and hash values, respectively' and then use the public key of the signature holder Decrypt the product of these two sums with the signature of all parts and decrypt the result. If the signature is verified, all the public key certificates received are legal. 1 0 'As described in item 7 of the scope of patent application Method for batch verification of multiple digital vouchers, wherein the processing unit is composed of a data processing unit. I ^ irin page 18 Page 19