In this paper we introduce a Time-Based Cryptosystem (TBC) scheme. This scheme requires a Time-Based Key Generation Center (TBKGC) to broadcast a set of public keys based on the Multi-prime RSA (MPRSA) at every new interval. The sender encrypts the plaintext with a specified period of time and the corresponding public key broadcast by the TBKGC. And the receiver acquires the corresponding key from the TBKGC to decrypt the ciphertext. We discuss the difference between TBC and Time-Specific Encryption (TSE). Finally we suggest extension and directions of improvement of TBC.
