143 results about "Blind signature" patented technology

The invention relates to an anonymous electronic voting method based on blockchain. A blind signature electronic voting scheme is introduced into blockchain as a vote information database, each vote is written into a transaction data block and transmitted to a counting center, in addition, a monitoring mechanism is introduced into the method, then rights of operators can be limited, and the situation that fraud voting is resulted or the voting process is interfered and voting results are affected since rights of operators are too centralized, is avoided. By adopting the method, the anonymity of a conventional electronic voting system is effectively solved, and the method has the characteristics that votes cannot be forged, the voting process and the voting results are open and transparentand can be verified, and the like.

A voter V_i encrypts his vote content v_i with a public key k_PC of a counter C, then concatenates the encrypted vote content x_i with a tag t_i to obtain a ballot z_i, then randomizes it with a random number r_i to create a preprocessed text e_i, and sends it and a signature s_i therefor to an election administrator A. The administrator A generates a blind signature d_i for the preprocessed text e_i and sends it back to the voter V_i. The voter V_i excludes the influence of the random number r_i from the blind signature d_i to obtain administrator signature y_i, and sends vote data <z_i, y_i> to a counter C. The counter C verifies the validity of the administrator signature y_i and, if valid, generates and publishes a vote list containing the data <z_i, y_i> to the voter V_i. The voter V_i checks the vote list to make sure that it contains the data <z_i, y_i> with his tag t_i held in the ballot z_i. The counter C decrypts the encrypted vote content x_i in the ballot z_i to obtain the vote content v_i, and counts the number of votes polled for each candidate.

The invention discloses a client secure deduplication method of ciphertext data in cloud storage. The method comprises the following steps of: (1) key generation; (2) file initialization; (3) data block initialization; (4) data block verification; (5) file storage; (6) challenge generation; (7) proof generation; (8) proof verification; and (9) file decryption. According to the method of the invention, a secure key generation protocol is constructed based on blind signature, and therefore, secondary encryption of convergence keys is realized, and the security of the keys can be ensured; and a signature-based ownership proving method is put forward based on the above encryption, and with the method adopted, it can be ensured that a user can prove his or her ownership of a certain file in the could storage to a could server in a safer and more efficient way, and file-level and block-level deduplication of a ciphertext file can be realized.

The invention provides a blockchain anonymous voting system and method. A voting system is realized by using a block chain; voting logic is put into an intelligent contract for operation; voting datacan be publicized and transparentized; a centralized node does not exist, even if a single node fault occurs, the overall operation of the system is not influenced;, the voting data in the blockchaincan be tampered by any person, and moreover, by introducing cryptographic technologies such as blind signature and ring signature into the blockchain, details such as identity information and voting intention of voters are hidden on the premise of ensuring the openness and legality of necessary voting data, so that the effect of protecting the privacy of users is achieved.

In an apparatus and a method for generating and verifying an identity based blind signature by using bilinear parings, a trust authority generates system parameters and selects a master key. Further, the trust authority generates a private key by using a signer's identity and the master key. The signer computes a commitment and sends the commitment to the user. The user blinds a message and sends the blinded message to the signer. The signer signs the blinded message and sends the signed message to the user. Thereafter, the user unblinds the signed message and then verifies the signature.

The present invention is aimed at the proposal of a limited blind signature system which is highly safe such that its safety can be proven without the assumption of a random oracle model. A signature presenting apparatus is supplied with a public key, a blind secret identifier, a blind public identifier, a blind signature, and a random number. A signature verifying apparatus outputs “valid” if the signature presenting apparatus is supplied with the data and otherwise outputs “invalid”.

The invention discloses a blockchain-based anonymous electronic voting method and a system thereof. The method comprises the following steps: voting terminal identity information and Ethereum accountaddress are sent to the registration center by the voting terminal, and a blind signature is generated at the registration center and sent to the voting terminal, and a voting right signature is output by the voting terminal; voting parameters are generated by a voting managing terminal, the parameters are included to a smart contract and sent to the blockchain network in a transaction manner forinformation announcement, the smart contract voting contents are obtained by the voting terminal, and vote messages at the voting terminal are issued to the smart contract of the voting managing terminal, and then a voting process is finished. When the set voting end time is reached, the voting managing terminal stops receiving votes in a smart contract manner and statistical results are obtained.The voting records can be checked at any time and cannot be falsified, and the voting fairness is improved. The ballots are separated from the true identity of the voting party, and the double anonymity protection of the voting terminal and the voting is realized, and the personal privacy of the voting terminal is better protected.

The invention discloses a blind signature generation method and system based on SM9 digital signature. The method comprises the following steps: 1) a key generation center KGC generates a signature private key DSA of a Signer; 2) the Signer calculates a first temporary variable w and sends the w to a User; 3) after the User receives the w, a second temporary variable w' and a hash value h) of a to-be-signed message M are generated, and a third temporary variable h' is calculated and sent to the Signer finally; 4) after the Signer receives the h', the temporary signature S' is calculated and sent to the User; 5) the User receives the S' and then calculates a signature value S, and outputs the signature (h, S). The method has the characteristics of low complexity, high security, easy verification, etc. The signature generation process must have both Signer and User participating simultaneously, and the process of generating the SM9 blind signature does not leak the signed message to thesigner, thus ensuring the security of the message, and improving the fairness of the SM9 digital signature generation.

An anonymous and secure on-line payment system and method based on the partially blind signature cryptographic method with revocable anonymity. To this end, an Anonymity Server (SA) enables the Customer (C) to acquire on-line anonymous payment means on the basis of a protocol that does not enable the Anonymity Server to link the payment means to the Customer (C). The Payment Server (SdP) comprises means for opening an anonymous account using the anonymous payment means (50). A Customer (C) can make an on-line purchase from a Merchant Site (SM) without having to give a bank card number and remaining anonymous to the merchant and more generally to any entity present in the transaction or absent therefrom. However, this anonymity may be revoked by a trusted entity in the event of fraud on the Customer. Finally, a Customer can make payments when on the move.

The invention discloses a blind signature method and a blind signature system. The method comprises the steps of selecting prime numbers p and q, and outputting a group Zp* with the order of the prime number q; randomly selecting two generators g1 and g2 in the group Zp*, and three random elements s1, s2 and t in a domain Zq; working out v according to a FORMULA; according to the information amount of signatures, selecting the size n of a batch; and working out n cryptographs through interactively using parallel batch processing index computation products by a client and a blind singer; and verifying the signatures in batches. The blind signature method has the advantages as follows compared with the general batch processing index computation product, about 25% computation quantity is saved, thus the computational pressure is effectively relieved; and during the verifying process, the n signatures are simultaneously verified by a batch verifying method, the computation time is effectively saved, only about 70% of the time of the general method is needed, and the efficiency is high.

Signature requestor terminal device (10) codes a plurality of messages to a quantum state and transmits it to signer terminal device (20). Signer terminal device (20) issues a blind signature for the plurality of the messages coded to the quantum state, codes the messages and the signature to a quantum state and sends them back to signature requestor terminal device (10).

The invention discloses a data security duplicate removal method based on a threshold blind signature. The invention relates to the field of digital signatures in information security, and solves theproblems that n key management nodes are adopted to perform blind signing on messages at the same time, a large amount of information needs to be interacted among the key management nodes, and the calculation overhead for verifying signatures is large. System initialization is firstly performed, and a main key node generates a public key and a public key; the n sub-key nodes are numbered as k1, k2,..., kn, and a t-1-order polynomial is constructed: f(x)=a0+a1x+...+a<t-1>x<t-1>; partial private keys corresponding to each sub-key node: f(k1), f(k2),...,f(kn), are calculated and safely transmitted to the sub-key nodes; and then the client blinds the message, and sends the blinded message to the sub-key node. And the sub-key node signs the message and returns the message to the client. And theclient uploads the ciphertext data to the cloud server. According to the method provided by the invention, a single-point fault problem does not exist, the main key node can be offline after initialization is completed, and the n sub-key nodes only need at least t available sub-key nodes to complete subsequent steps.

The invention is applicable to the technical field of information security and provides a CL-PBS (certificateless partially blind signature) method. The method comprises the steps as follows: a public system parameter params=[G1, G2, P, e, g, H0, H1, H2, Ppub] is established; a signer extracts a private key shown in the specification and a public key shown in the specification; a signer randomly selects an icon shown in the specification, calculates z=H0(c) and R=rP and sends R to a signature requester; the signature requester randomly selects a blinding factor shown in the specification after receiving the R, calculates formulas shown in the specification and sends h to the signer; the signer calculates a formula shown in the specification and sends S to the signature requester after receiving h; the signature requester conducts de-blinding work and calculates S'=alphaS to obtain a signature sigma=(y, h', S') of a message m and a consultation message c; a verifier verifies the signature. The method effectively solves the security problems caused by tapering of consultation public information in CL-PBS.

The invention discloses an anonymous secure payment channel method and a device, and the method comprises the steps: enabling two transaction parties to communicate on the Internet, determining the willingness of a transaction, selecting a path, determining a transaction man-in-the-middle, and building deployment intelligent contracts with the transaction man-in-the-middle, so as to build a channel; transmitting a virtual channel opening certificate between the two transaction parties and the transfer intermediary; controlling two transaction parties to perform transaction, and sending transaction certificates to each other; sending a final result of a transaction to a transaction intermediary through a first transaction user; and performing calculation by the transaction intermediary, sending a blind signature certificate for closing settlement to the first transaction user after confirmation, performing exchange with a certificate for closing the channel with the first transaction user, and the first transaction user carries out blind removal processing on the received blind signature certificate and forwards the blind signature certificate to the second transaction user for closing the channel. The method can realize non-linkable identities of both parties in a transaction process, and is suitable for most blockchain networks supporting smart contracts.

The invention provides a partially blind signature method based on identity and relates to the technical field of information security. The partially blind signature method based on identity is capable of reducing the calculation complexity and improving the execution efficiency. The method comprises the following steps: public system parameters {G1, q, 1, P, G2, e, H1, H2, H3, QPKG} are established by PSK and an integer sPKG is randomly selected as a private key for secret storage from the integral multiplicative group as shown in the description of mod q; a signer sends own identity information as shown in the description to a private key generation center, the private key generation center generates the private key Did of the signer and sends the private key Did to the signer via a security authentication channel, and then the signal obtains the private key Sid and confirms that the private key is generated by the private key generation center; next, the signer signs; a verifier verifies the validity of the signature by use of the public key of the signer. The partially blind signature method based on identity can be applied to electronic cash, electronic voting and electron transactions.

The invention relates to a reputation evaluation method and system for privacy protection based on a block chain, and belongs to the technical field of blind signatures, secure multi-party signaturesand block chains. After the user and the merchant finish the online transaction, anonymous evaluation is carried out on the merchant to generate an evaluation transaction, the evaluation transaction is sent to the alliance block chain network, each service provider carries out partial decryption on the evaluation in the evaluation transaction and sends the evaluation to the block chain network, and the merchant updates the reputation of the merchant according to the partial decryption information. Specifically, the method comprises the following steps: a user, a merchant and a service providerregister with a trusted party to obtain corresponding keys; and the user accesses the reputation of the merchant under each service provider, evaluates the service provider after online transaction,broadcasts the reputation in a block chain transaction form, and the service provider serves as a miner of the block chain network, calculates the obtained evaluation for all merchants and updates themerchants. The method and the system have the advantages of reputation publicity, reputation availability, data audit and effective privacy protection for user evaluation.

The invention provides blind digital signature system and method based on a braid group. The system comprises a key generating device, an information blinding device, a signing device and a signature de-blinding device, wherein the key generating device is used for generating public keys and private keys based on system parameters; the information blinding device is used for selecting blinding factors based on the system parameters and calculating the selected blinding factors and information to be signed based on the conjugation operation to generate a blinding information braid; the signing device is used for calculating the private keys generated by the key generating device and the blinding information braid to be signed based on the conjugation operation to generate a blinding signature braid; and the signature de-blinding device is used for calculating the blinding factors and the blinding signature braid based on the conjugation operation to generate a signature braid and combining the information to be signed and the de-blinded signature braid into a whole signature, therefore, the blind digital signature based on the braid group can be verified in the aspect of safety, hopefully stands against the known quantum analysis, and is more suitable for the application scenes of the blind digital signature, such as electronic money and the like.

In a fair blind signature process, a user interacts with a signer in order to complete a 7-tuple (A,e,s,t,x_u,x,m) such that A^e=a₀α₁^x α₂^m α₃^{<sub2>u </sub2>}α₄^t α₅^s (mod n), where a₀, a₁, a₂, a₃, a₄ and a₅ and n are elements of the Signer's public key (PUBK_s). During the signature-issuing phase the user (U) provides the signer (S) with a data element (α₁^x) encrypted according to a key (f) known to a trusted authority (TA), and this data element (α₁^x) is disclosed during transmission of the signed message. Similarly, the signed message is transmitted associated with second encrypted data comprising a second data element (α₃^{x<sub2>u</sub2>}) encrypted according to a key (f) known to the trusted authority (TA), and this second data element (α₃^{x<sub2>u</sub2>}) is disclosed to the Signer during the signature-issuing phase. Thus, the trusted authority (TA) can revoke the anonymity of the digital signature.

The invention discloses a blind signcryption method under a lattice public key cryptosystem. The blind signcryption method is characterized by comprising the steps of system initialization, user key generation, message owner blinding message, user signature, encryption and verification. According to the invention, by referencing a blind signcryption and lattice password method under a traditionalpassword system, a lattice-based post-quantum blind signcryption method is constructed, so that the blind signcryption efficiency is higher than the efficiency of blind signature before encryption, compared with a lattice-based blind signature method, an encryption function is added, and relative to a blind signcryption method under the assumption of finite field discrete logarithm and elliptic curve discrete logarithm, due to the fact that the blind determination message Mu is added in the signcryption scheme, the blind function is added, the signcryption has anonymity, the privacy of a message owner is effectively protected, the quantum attack can be resisted, the calculation efficiency is higher, and the method can be used for the technical field of electronic signcryption.