SHA1MessageDigest

Developer Reference for Intel® Integrated Performance Primitives Cryptography

Computes SHA-1 digest value of the input message.

Syntax

IppStatus ippsSHA1MessageDigest(const Ipp8u *pMsg, int len, Ipp8u *pMD);

Include Files

ippcp.h

Parameters

pMsg	Pointer to the input message.
len	Message length in octets.
pMD	Pointer to the resultant digest.

Description

The function uses the selected hash algorithm to compute the digest value of the entire (non-streaming) input message.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or warning.
ippStsNullPtrErr	Indicates an error condition if any of the specified pointers is NULL.
ippStsLengthErr	Indicates an error condition if the input data stream length is less than zero.

Example

The code example below shows SHA1 digest of a message.

    //    Compute two SHA1 digests of a message:
    //    1-st will correspond of 1/2 message
    //    2-nd will correspond of whole message
void SHA1_sample(void){
   // get size of the SHA1 context
   int ctxSize;
   ippsSHA1GetSize(&ctxSize);

   // allocate the SHA1 context
   IppsSHA1State* pCtx = (IppsSHA1State*)( new Ipp8u [ctxSize] );
   // and initialize the context
   ippsSHA1Init(pCtx);
   // define a message
   Ipp8u msg[] = "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq";
   int n;
   // update digest using a piece of message
   for(n=0; n<(sizeof(msg)-1)/2; n++)
      ippsSHA1Update(msg+n, 1, pCtx);
// clone the SHA1 context
   IppsSHA1State* pCtx2 = (IppsSHA1State*)( new Ipp8u [ctxSize] );
   ippsSHA1Init(pCtx2);
   ippsSHA1Duplicate(pCtx, pCtx2);
 // finalize and extract digest of a half message
   Ipp8u digest[20];
   ippsSHA1Final(digest, pCtx);
   // update digest using the SHA1 clone context
   ippsSHA1Update(msg+n, sizeof(msg)-1-n, pCtx2);

   // finalize and extract digest of a whole message
   Ipp8u digest2[20];
   ippsSHA1Final(digest2, pCtx2);

   delete [] (Ipp8u*)pCtx;
   delete [] (Ipp8u*)pCtx2;
}