GUID-99EF313F-E857-4804-8990-BC649E34815C.md

CRYPT_ECC_DSA_HashSign Function

Parent topic:MPLAB® Harmony Crypto Library

C

int CRYPT_ECC_DSA_HashSign(
    CRYPT_ECC_CTX* ecc, 
    CRYPT_RNG_CTX* rng, 
    unsigned char* sig, 
    unsigned int sigSz, 
    unsigned int* usedSz, 
    const unsigned char* in, 
    unsigned int inSz
);

Description

This function takes a message digest and signs it using a private ECC key.

Preconditions

The ECC context must have been initialized with a call to CRYPT_ECC_Initialize. The RNG context must have been initialized with a call to CRYPT_RNG_Initialize. The private key used for the signature must have been imported or created prior to calling this function.

Parameters

Parameters	Description
ecc	Pointer to ECC context which saves state between calls and holds keys.
rng	Pointer to Random Number Generator context.
sig	Destination for the signature.
sigSz	The max size of the signature, in bytes.
usedSz	The resulting size of the signature, in bytes.
in	Pointer to the message digest to sign.
inSz	The length of the digest, in bytes.

Returns

• BAD_FUNC_ARG - An invalid pointer was passed to the function.

• 0 - An invalid pointer was not passed to the function.

Remarks

None.

Example

CRYPT_ECC_CTX userA; 
int           ret;
byte          sig[100];
unsigned int  sigSz = (unsigned int)sizeof(sig);
unsigned int  usedA = 0;

ret = CRYPT_ECC_Initialize(&userA);
...
// Import or generate private key
...
ret = CRYPT_ECC_DSA_HashSign(&userA, &mcRng, sig, sigSz, &usedA, ourData, CRYPT_SHA_DIGEST_SIZE);