DecInit

Synopsis

#include “fmciphobj.h”
int (*DecInit)(struct CipherObj * ctx,
int mode,
const void * key, unsigned int klength,
const void * param, unsigned int plength);
 

Description

This function initializes the cipher object for a decrypt operation. It must be called prior to any DecryptUpdate or DecryptFinal calls.

Parameters

Parameter	Description
ctx	The address of a cipher object instance.
mode	The encrypt mode. Different algorithms support different values for this parameter. Please consult Algorithm-Specific Cipher Information for the possible values for a certain algorithm.
key	The address of a buffer containing the key value. The encoding of the key is algorithm-dependent. However, for most block ciphers, this buffer contains the key value. Please consult Algorithm-Specific Cipher Information for key encoding information.
klength	Number of bytes in the key buffer.
param	The address of the buffer containing various parameters for the encrypt operation. The contents and the encoding of this buffer are algorithm and mode dependent. However, for most block ciphers this buffer contains the IV when one of the CBC modes is used. Please consult Algorithm-Specific Cipher Information for key encoding information.
plength	Number of bytes in the param buffer.

Return Value

0: The operation was successful.

Otherwise: An error occurred.