ica_aes_cfb

Purpose

Encrypt or decrypt data with an AES key using Cipher Feedback (CFB) mode, as described in NIST Special Publication 800-38A Chapter 6.3.

Required hardware support

KMF-AES-128, KMF-AES-192, or KMF-AES-256

Parameters

const unsigned char *in_data

Pointer to a readable buffer that contains the message to be encrypted or decrypted. The size of the message in bytes is data_length. The size of this buffer must be at least as large as data_length.

unsigned char *out_data

Pointer to a writable buffer to contain the resulting encrypted or decrypted message. The size of this buffer in bytes must be at least as large as data_length.

unsigned long data_length

Length in bytes of the message to be encrypted or decrypted, which resides at the beginning of in_data.

const unsigned char *key

Pointer to a valid AES key.

unsigned int key_length

Length in bytes of the AES key. Supported sizes are 16, 24, and 32, for AES-128, AES-192, and AES-256 respectively. Therefore, you can use the definitions: AES_KEY_LEN128, AES_KEY_LEN192, and AES_KEY_LEN256.

unsigned char *iv

Pointer to a valid initialization vector of the same size as the cipher block in bytes (16 bytes for AES). This vector is overwritten during the function. The result value in iv can be used as the initialization vector for a chained ica_aes_cfb call with the same key, if the data_length in the preceding call is a multiple of lcfb.

unsigned int lcfb

Length in bytes of the cipher feedback, which is a value greater than or equal to 1 and less than or equal to the cipher block size (16 bytes for AES).

unsigned int direction

0

Use the decrypt function.

1

Use the encrypt function.

Return codes

0

Success

For return codes indicating exceptions, see Return codes.