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/*
//
// Purpose:
// Intel(R) Integrated Performance Primitives. Cryptography Primitives.
// EC over GF(p) Operations
//
// Context:
// ippsGFpECSetPointHash_rmf()
//
*/
#include "owndefs.h"
#include "owncp.h"
#include "pcpgfpecstuff.h"
#include "pcphash.h"
#include "pcphash_rmf.h"
/*F*
// Name: ippsGFpECSetPointHash_rmf
//
// Purpose: Constructs a point on an elliptic curve based on the hash of the input message
//
// Returns: Reason:
// ippStsNullPtrErr pPoint == NULL
// pEC == NULL
// pScratchBuffer == NULL
// (msgLen && !pMsg)
// pMethod == NULL
//
// ippStsContextMatchErr invalid pEC->idCtx
// invalid pPoint->idCtx
//
// ippStsBadArgErr !GFP_IS_BASIC(pGFE)
//
// ippStsOutOfRangeErr ECP_POINT_FELEN(pPoint)!=GFP_FELEN()
//
// ippStsQuadraticNonResidueErr square of the Y-coordinate of
// the pPoint is a quadratic non-residue modulo
//
// ippStsLengthErr msgLen<0
//
// ippStsNoErr no error
//
// Parameters:
// hdr Header of the input message
// pMsg Pointer to the input message
// msgLen Length of the input message
// pPoint Pointer to the IppsGFpECPoint context
// pEC Pointer to the context of the elliptic curve
// pMethod Pointer to the hash method
// pScratchBuffer Pointer to the scratch buffer
//
// Note:
// Is not a fact that computed point belongs to BP-related subgroup BP
//
*F*/
IPPFUN(IppStatus, ippsGFpECSetPointHash_rmf,(Ipp32u hdr, const Ipp8u* pMsg, int msgLen, IppsGFpECPoint* pPoint,
IppsGFpECState* pEC, const IppsHashMethod* pMethod,
Ipp8u* pScratchBuffer))
{
IppsGFpState* pGF;
gsModEngine* pGFE;
/* test method pointer */
IPP_BAD_PTR1_RET(pMethod);
/* test message length */
IPP_BADARG_RET((msgLen<0), ippStsLengthErr);
/* test message pointer */
IPP_BADARG_RET((msgLen && !pMsg), ippStsNullPtrErr);
IPP_BAD_PTR3_RET(pPoint, pEC, pScratchBuffer);
pEC = (IppsGFpECState*)( IPP_ALIGNED_PTR(pEC, ECGFP_ALIGNMENT) );
IPP_BADARG_RET( !ECP_TEST_ID(pEC), ippStsContextMatchErr );
pGF = ECP_GFP(pEC);
pGFE = GFP_PMA(pGF);
IPP_BADARG_RET( !GFP_IS_BASIC(pGFE), ippStsBadArgErr );
IPP_BADARG_RET( !ECP_POINT_TEST_ID(pPoint), ippStsContextMatchErr );
IPP_BADARG_RET( ECP_POINT_FELEN(pPoint)!=GFP_FELEN(pGFE), ippStsOutOfRangeErr);
{
int elemLen = GFP_FELEN(pGFE);
BNU_CHUNK_T* pModulus = GFP_MODULUS(pGFE);
Ipp8u md[IPP_SHA512_DIGEST_BITSIZE/BYTESIZE];
int hashLen = pMethod->hashLen;
BNU_CHUNK_T hashVal[BITS_BNU_CHUNK(IPP_SHA512_DIGEST_BITSIZE)+1];
int hashValLen;
IppsHashState_rmf hashCtx;
ippsHashInit_rmf(&hashCtx, pMethod);
{
BNU_CHUNK_T* pPoolElm = cpGFpGetPool(1, pGFE);
/* convert hdr => hdrStr */
BNU_CHUNK_T locHdr = (BNU_CHUNK_T)hdr;
Ipp8u hdrOctStr[sizeof(hdr/*locHdr*/)];
cpToOctStr_BNU(hdrOctStr, sizeof(hdrOctStr), &locHdr, 1);
/* compute md = hash(hrd||msg) */
ippsHashUpdate_rmf(hdrOctStr, sizeof(hdrOctStr), &hashCtx);
ippsHashUpdate_rmf(pMsg, msgLen, &hashCtx);
ippsHashFinal_rmf(md, &hashCtx);
/* convert hash into the integer */
hashValLen = cpFromOctStr_BNU(hashVal, md, hashLen);
hashValLen = cpMod_BNU(hashVal, hashValLen, pModulus, elemLen);
cpGFpSet(pPoolElm, hashVal, hashValLen, pGFE);
if( gfec_MakePoint(pPoint, pPoolElm, pEC)) {
/* set y-coordinate of the point (positive or negative) */
BNU_CHUNK_T* pY = ECP_POINT_Y(pPoint);
if(pY[0] & 1)
cpGFpNeg(pY, pY, pGFE);
/* update point if cofactor>1 */
if(ECP_SUBGROUP(pEC))
gfec_MulPoint(pPoint, pPoint, ECP_COFACTOR(pEC), GFP_FELEN(pGFE), /*0,*/ pEC, pScratchBuffer);
cpGFpReleasePool(1, pGFE);
return ippStsNoErr;
}
}
cpGFpReleasePool(1, pGFE);
return ippStsQuadraticNonResidueErr;
}
}