VerifyFinal

Synopsis

#include “fmciphobj.h”
int (*VerifyFinal)(struct CipherObj * ctx,
const void * sig, unsigned int slength,
void * tgt, unsigned int tlength, unsigned int * plen);
 

Description

This function must be called to finish a signature or MAC verification operation. It can be used for either discovering the target buffer length, or for actually performing the operation.

If the target buffer address, tgt, is NULL, then the variable pointed to by plen is updated to contain the length of the output that is required to perform the operation.

If the target buffer address is not NULL, then the verification operation is completed. In addition to the verification, the recovered signature is placed in the output buffer.

Parameters

Parameter	Description
ctx	The address of a cipher object instance.
sig	The address of the buffer containing the signature or the MAC.
slength	Number of bytes in the sig buffer.
tgt	The address of the output buffer. It may be set to NULL for output buffer length estimation.
tlength	Total number of bytes available in the output buffer.
plen	Address of a variable that will receive the number of bytes placed in the target buffer. This variable must not be NULL.

Return Value

0: The signature or MAC was correct.

Otherwise: there was an error, or the signature or MAC was incorrect.

Comments

This function finalizes the verification context. VerifyInit() must be called again to verify more data, even when the key is the same.