56.4.3 Last Output Data Mode (CBC_MAC)

This mode is used to generate cryptographic checksums on data (MAC) by means of cipher block chaining encryption algorithm (CBC-MAC algorithm for example).

The CMAC algorithm is a variant of CBC-MAC with post-processing requiring one-block encryption in ECB mode. Thus CBC-MAC is useful to accelerate CMAC.

After each end of encryption/decryption, the output data are available either on AES_ODATARx for Manual and Auto mode, or at the address specified in the receive buffer pointer for DMA mode (see the table "Last Output Data Mode Behavior versus Start Modes").

AES_MR.LOD allows retrieval of only the last data of several encryption/decryption processes.

Therefore, there is no need to define a read buffer in DMA mode.

This data are only available in AES_ODATARx.