| 摘要 |
PROBLEM TO BE SOLVED: To provide a cryptographic system and a method for supporting multiple modes of operation such as CBC, CTR and/or CCM modes. SOLUTION: A method for encrypting data includes the steps of: reading a plaintext data block from a memory (S20); storing the plaintext data block in an input buffer (S20); encrypting the plaintext data block in the input buffer using a first mode to generate a first ciphertext (S21); storing the first ciphertext in an output buffer (S22); and encrypting the plaintext data block in the input buffer using a second mode to generate a second ciphertext (S23). For example, in a CCM operation mode wherein the first mode is a CTR (counter) mode and the second mode is a CBC (cipher block chaining) mode, the plaintext block that is initially read from the memory and stored in the data input register is applied to both the CTR and CBC modes, thereby the number of memory read operations is reduced. COPYRIGHT: (C)2004,JPO&NCIPI |
