ica_des_ofb

Purpose

Encrypt or decrypt data with a DES key using Output Feedback (OFB) mode, as described in NIST Special Publication 800-38A Chapter 6.4.

Format

unsigned int ica_des_ofb(const unsigned char *in_data,
  unsigned char *out_data,
  unsigned long data_length,
  const unsigned char *key,
  unsigned int key_length,
  unsigned char *iv,
  unsigned int direction);

Required hardware support

KMO-DEA

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 that contains the resulting encrypted or decrypted message. The size of this buffer 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 DES key of 8 bytes in length.

unsigned char *iv

Pointer to a valid initialization vector of the same size as the cipher block in bytes (8 bytes for DES). This vector is overwritten during the function. If data_length is a multiple of the cipher block size (8 bytes for DES), the result value in iv can be used as the initialization vector for a chained ica_des_ofb call with the same key.

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.