QuickCrypt Library

API

CBC Mode API Overview

CBC Mode API assists you in performing encryption/decryption in CBC mode of operation.

To encrypt/decrypt a continuous memory buffer, perform the following:

• Allocate at least CONTEXTSIZE bytes for the context. For example, to perform DES encryption/decryption allocate at least SLC_DES_CONTEXTSIZE bytes for the context.

• Call the Init function of the encryption algorithm you need to use, passing to it the secret key and the cipher direction (SLC_ENCRYPT  or SLC_DECRYPT). For example, to perform DES encryption/decryption call SL_DES_Init function.

• Call the SL_CBC_Init function to initialize the context with the initialization vector and with the cipher direction (SLC_ENCRYPT or SLC_DECRYPT). The cipher direction must be the same as in previous step.

• Call the SL_CBC_Process function to encrypt/decrypt the memory buffer.

  Note. The SL_CBC_Process function can be replaced with SL_CBC_ProcessBlock and SL_CBC_ProcessLastBlock functions. Divide the memory buffer into blocks of BLOCKSIZE bytes each and call SL_CBC_ProcessBlock function for each of them. If the last block that has to be processed is shorter than BLOCKSIZE bytes call SL_CBC_ProcessLastBlock function instead of SL_CBC_ProcessBlock.

CBC Mode API Functions   |   Useful Links