| 摘要 |
Authenticated encryption scheme based on stream ciphers and hash functions with in-advance and parallel computation, using random numbers whose length is shorter than 2N with respect to the message length N. The random numbers are generated using a pseudo random-number generator, and divided into blocks. The plaintext is divided into blocks too. Next, the exclusive-OR logical sums of random-number blocks Ri (1≤i≤N) and plaintext blocks Pi (1≤i≤N) are calculated, thereby acquiring ciphertext blocks Ci (1≤i≤N). A hash function (NHR(S)) on the random-number blocks Ri (2≤i≤N+1) and the ciphertext blocks Ci (1≤i≤N) is calculated as well, thereby generating (CN+1 and N+2) the message authentication code (MAC) of the generated ciphertext (1022) Ci (1≤i≤N). The random number generation can be carried out in advance of the authenticated encryption, wherein the generation of the ciphertext and the message authentication code can be executed in parallel. This increases the overall speed of the scheme. <IMAGE> |
