Patent ID: 7529366

Claim:
A method for block encryption comprising: transferring plaintext data stored in a first memory to a second memory; loading to an initial value memory an initial value; loading into a register a mode indication indicating a mode of encryption to be executed on the plaintext data and an initial value flag indicating whether a block of the plaintext data is an initial block; transferring the plaintext data from the second memory to an encryption circuit, through a data control circuit, in blocks of predetermined length; transferring the initial value from the initial value memory to an exclusive-OR circuit in the data control circuit, and transferring the mode indication and initial value flag from the register to a latch in the data control circuit; encrypting the plaintext data in the encryption circuit in blocks of predetermined length based on the transferred initial value, the transferred mode indication, and the transferred initial value flag; transferring the encrypted data to the second memory; and transferring the encrypted data to the first memory when the encrypted data stored in the second memory reaches a predetermined size exceeding the block length.