SYSTEM FOR PROTECTED STORAGE AND MANAGEMENT IN A TTP SERVER

摘要

System for protected storage in a TTP server. A file (Txt) is transmitted from a first (A) to a second user (B) after being enciphered with a session key (SesKey), which is enciphered with the public key (PublKeyB) of the second user. The session key (SesKey) is also enciphered by the first user with the public key (PublKey/TTP) of the TTP server which, after having received it, deciphers said session key with his private key (SecKeyTTP). The TTP server subsequently enciphers the session key (SesKey) and the (original) public key (PubKeyA) of the first user (A) with a "public" storage key (PubStorKey). The enciphered session key ((SesKey)PubStorKey) and public key ((PubKeyA)PubStorKey) of the first user are stored, together with the enciphered file ((Txt)SesKey), in a storage medium (DB). They are recoverable by the TTP, by deciphering with the private storage key (SecStorKey), and may be transmitted after having been enciphered with the current public keys (PubKeyA' or PubKeyB', as the case may be) of the users.