The essence of the invention is in that when making a digital blind RSA-signature a new technique for blinding an initial data by a RSA-encryption and corresponding technique for unblinding the signed blinded data are employed, which gives the possibility to use an unlimited number of kinds of the signature in electronic systems of the mass scale service. The untraceability is ensured by a corresponding choice of the randomized exponent R, RSA-key used in RSA-encryption the initial data, and by the public module N properties verified in an arbitrary time moment. In so doing, N=PQ, where P and Q are secret prime factors, and R is multiple to N-1. In other variants of the invention the diversity of kinds of the signature is set by limitings on multiplicities of public exponents, said limitings being chosen prior to blinding the initial data. The apparatus to realize the method for making a digital blind RSA-signature comprises a blinding unit based on a modular exponentiator, and a corresponding unblinding unit.
A security system using an RSA algorithm that includes a key input section for receiving a secret key and a public key used in one of encryption and decryption of a message, a random coefficient generating section for generating a random coefficient r having a bit of a predetermined size, a first calculation section for dividing the secret key into a first secret key and a second secret key by using the value of r, and performing an exponentiation of RSA algorithm by using the respective secret keys and the public key, and a second calculation section for performing one of the encryption and the decryption by combining results of exponentiation calculated respectively by using the first and the second secret keys.
A method and system for utilizing and encryption or decryption agent so as to preclude access by the encryption agent or decryption agent, respectively, to the information being encrypted or decrypted. To preclude access by the encryption agent, a blinding function is applied to the information prior to forwarding such information to the encryption agent for encryption. To preclude access to the information by the decryption agent, a blinding function is applied to the encrypted information prior to forwarding the encrypted information to the decryption agent for decryption. Once the information has been returned, the information is unblinded, leaving an encrypted or decrypted message respectively.
