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/*
// Intel(R) Integrated Performance Primitives. Cryptography Primitives.
//
// Context:
// ippsGFpECVerifyNR()
//
*/
#include "owndefs.h"
#include "owncp.h"
#include "pcpeccp.h"
/*F*
// Name: ippsGFpECVerifyNR
//
// Purpose: NR Signature Verification.
//
// Returns: Reason:
// ippStsNullPtrErr NULL == pEC
// NULL == pMsgDigest
// NULL == pRegPublic
// NULL == pSignR
// NULL == pSignS
// NULL == pResult
// NULL == pScratchBuffer
//
// ippStsContextMatchErr illegal pEC->idCtx
// pEC->subgroup == NULL
// illegal pMsgDigestDigest->idCtx
// illegal pRegPublic->idCtx
// illegal pSignR->idCtx
// illegal pSignS->idCtx
//
// ippStsMessageErr 0> MsgDigest
// order<= MsgDigest
//
// ippStsRangeErr SignR < 0 or SignS < 0
//
// ippStsOutOfRangeErr bitsize(pRegPublic) != bitsize(prime)
//
// ippStsNotSupportedModeErr 1<GFP_EXTDEGREE(pGFE)
//
// ippStsNoErr no errors
//
// Parameters:
// pMsgDigest pointer to the message representative to being signed
// pRegPublic pointer to the regular public key
// pSignR,pSignS pointer to the signature
// pResult pointer to the result: ippECValid/ippECInvalidSignature
// pEC pointer to the ECCP context
// pScratchBuffer pointer to buffer (2 mul_point operation)
//
*F*/
IPPFUN(IppStatus, ippsGFpECVerifyNR,(const IppsBigNumState* pMsgDigest,
const IppsGFpECPoint* pRegPublic,
const IppsBigNumState* pSignR, const IppsBigNumState* pSignS,
IppECResult* pResult,
IppsGFpECState* pEC,
Ipp8u* pScratchBuffer))
{
IppsGFpState* pGF;
gsModEngine* pGFE;
/* EC context and buffer */
IPP_BAD_PTR2_RET(pEC, pScratchBuffer);
pEC = (IppsGFpECState*)( IPP_ALIGNED_PTR(pEC, ECGFP_ALIGNMENT) );
IPP_BADARG_RET(!ECP_TEST_ID(pEC), ippStsContextMatchErr);
IPP_BADARG_RET(!ECP_SUBGROUP(pEC), ippStsContextMatchErr);
pGF = ECP_GFP(pEC);
pGFE = GFP_PMA(pGF);
IPP_BADARG_RET(1<GFP_EXTDEGREE(pGFE), ippStsNotSupportedModeErr);
/* test message representative */
IPP_BAD_PTR1_RET(pMsgDigest);
pMsgDigest = (IppsBigNumState*)( IPP_ALIGNED_PTR(pMsgDigest, ALIGN_VAL) );
IPP_BADARG_RET(!BN_VALID_ID(pMsgDigest), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pMsgDigest), ippStsMessageErr);
/* test regular public key */
IPP_BAD_PTR1_RET(pRegPublic);
IPP_BADARG_RET( !ECP_POINT_TEST_ID(pRegPublic), ippStsContextMatchErr );
IPP_BADARG_RET( ECP_POINT_FELEN(pRegPublic)!=GFP_FELEN(pGFE), ippStsOutOfRangeErr);
/* test signature */
IPP_BAD_PTR2_RET(pSignR, pSignS);
pSignR = (IppsBigNumState*)( IPP_ALIGNED_PTR(pSignR, ALIGN_VAL) );
pSignS = (IppsBigNumState*)( IPP_ALIGNED_PTR(pSignS, ALIGN_VAL) );
IPP_BADARG_RET(!BN_VALID_ID(pSignR), ippStsContextMatchErr);
IPP_BADARG_RET(!BN_VALID_ID(pSignS), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pSignR), ippStsRangeErr);
IPP_BADARG_RET(BN_NEGATIVE(pSignS), ippStsRangeErr);
/* test result */
IPP_BAD_PTR1_RET(pResult);
{
IppECResult vResult = ippECInvalidSignature;
gsModEngine* pMontR = ECP_MONT_R(pEC);
BNU_CHUNK_T* pOrder = MOD_MODULUS(pMontR);
int orderLen = MOD_LEN(pMontR);
/* test mesage: msg<order */
IPP_BADARG_RET((0<=cpCmp_BNU(BN_NUMBER(pMsgDigest), BN_SIZE(pMsgDigest), pOrder, orderLen)), ippStsMessageErr);
/* test signature value */
if(!cpEqu_BNU_CHUNK(BN_NUMBER(pSignR), BN_SIZE(pSignR), 0) &&
!cpEqu_BNU_CHUNK(BN_NUMBER(pSignS), BN_SIZE(pSignS), 0) &&
0>cpCmp_BNU(BN_NUMBER(pSignR), BN_SIZE(pSignR), pOrder, orderLen) &&
0>cpCmp_BNU(BN_NUMBER(pSignS), BN_SIZE(pSignS), pOrder, orderLen)) {
int elmLen = GFP_FELEN(pGFE);
int pelmLen = GFP_PELEN(pGFE);
BNU_CHUNK_T* h1 = cpGFpGetPool(3, pGFE);
BNU_CHUNK_T* h2 = h1+pelmLen;
BNU_CHUNK_T* f = h2+pelmLen;
IppsGFpECPoint P;
cpEcGFpInitPoint(&P, cpEcGFpGetPool(1, pEC),0, pEC);
/* P = [d]BasePoint + [c]publicKey */
ZEXPAND_COPY_BNU(h1, orderLen, BN_NUMBER(pSignS),BN_SIZE(pSignS));
ZEXPAND_COPY_BNU(h2, orderLen, BN_NUMBER(pSignR),BN_SIZE(pSignR));
gfec_BasePointProduct(&P,
h1, orderLen, pRegPublic, h2, orderLen,
pEC, pScratchBuffer);
/* get P.X */
if(gfec_GetPoint(h1, NULL, &P, pEC)) {
/* x = int(P.x) mod order */
GFP_METHOD(pGFE)->decode(h1, h1, pGFE);
elmLen = cpMod_BNU(h1, elmLen, pOrder, orderLen);
cpGFpElementPadd(h1+elmLen, orderLen-elmLen, 0);
/* and recover msg f = (signC -x) mod order */
ZEXPAND_COPY_BNU(f, orderLen, BN_NUMBER(pMsgDigest),BN_SIZE(pMsgDigest));
cpModSub_BNU(h1, h2, h1, pOrder, orderLen, h2);
if(GFP_EQ(f, h1, orderLen))
vResult = ippECValid;
}
cpEcGFpReleasePool(1, pEC);
cpGFpReleasePool(3, pGFE);
}
*pResult = vResult;
return ippStsNoErr;
}
}