Mediated RSA cryptographic method and system

摘要

A mediated RSA cryptographic method and system is provided in which a sender encrypts a message using an encryption exponent e and a public modulus n, and a recipient and a trusted authority cooperate with each other to decrypt the encrypted message by using respective components d_U, d_T of a decryption exponent. In order to prevent the trusted authority from reading the message in the event that it has access to the recipient decryption exponent components d_U, the recipient blinds the encrypted message before passing it to the trusted authority. This blinding is effected by a modulo-n blinding operation using a factor r^e where r is a secret random number. The trusted authority then applies its decryption exponent component d_T to the message and returns the result to the recipient who cancels the blinding and applies its decryption exponent component d_U.