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/*############################################################################
# Copyright 1999-2018 Intel Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
############################################################################*/
/*
// Purpose:
// Cryptography Primitive.
// EC over Prime Finite Field (Verify Signature, DSA version)
//
// Contents:
// ippsECCPVerifyDSA()
//
*/
#include "owndefs.h"
#include "owncp.h"
#include "pcpeccp.h"
/*F*
// Name: ippsECCPVerifyDSA
//
// Purpose: Verify Signature (DSA version).
//
// Returns: Reason:
// ippStsNullPtrErr NULL == pECC
// NULL == pMsgDigest
// NULL == pSignX
// NULL == pSignY
// NULL == pResult
//
// ippStsContextMatchErr illegal pECC->idCtx
// illegal pMsgDigest->idCtx
// illegal pSignX->idCtx
// illegal pSignY->idCtx
//
// ippStsMessageErr MsgDigest >= order
//
// ippStsNoErr no errors
//
// Parameters:
// pMsgDigest pointer to the message representative to be signed
// pSignX,pSignY pointer to the signature
// pResult pointer to the result: ippECValid/ippECInvalidSignature
// pECC pointer to the ECCP context
//
// Note:
// - signer's key must be set up in ECCP context
// before ippsECCPVerifyDSA() usage
//
*F*/
IPPFUN(IppStatus, ippsECCPVerifyDSA,(const IppsBigNumState* pMsgDigest,
const IppsBigNumState* pSignX, const IppsBigNumState* pSignY,
IppECResult* pResult,
IppsECCPState* pEC))
{
/* use aligned EC context */
IPP_BAD_PTR1_RET(pEC);
pEC = (IppsGFpECState*)( IPP_ALIGNED_PTR(pEC, ECGFP_ALIGNMENT) );
IPP_BADARG_RET(!ECP_TEST_ID(pEC), ippStsContextMatchErr);
/* test message representative */
IPP_BAD_PTR1_RET(pMsgDigest);
pMsgDigest = (IppsBigNumState*)( IPP_ALIGNED_PTR(pMsgDigest, BN_ALIGNMENT) );
IPP_BADARG_RET(!BN_VALID_ID(pMsgDigest), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pMsgDigest), ippStsMessageErr);
/* test result */
IPP_BAD_PTR1_RET(pResult);
/* test signature */
IPP_BAD_PTR2_RET(pSignX,pSignY);
pSignX = (IppsBigNumState*)( IPP_ALIGNED_PTR(pSignX, BN_ALIGNMENT) );
pSignY = (IppsBigNumState*)( IPP_ALIGNED_PTR(pSignY, BN_ALIGNMENT) );
IPP_BADARG_RET(!BN_VALID_ID(pSignX), ippStsContextMatchErr);
IPP_BADARG_RET(!BN_VALID_ID(pSignY), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pSignX), ippStsRangeErr);
IPP_BADARG_RET(BN_NEGATIVE(pSignY), ippStsRangeErr);
{
IppECResult vResult = ippECInvalidSignature;
gsModEngine* pModEngine = ECP_MONT_R(pEC);
BNU_CHUNK_T* pOrder = MOD_MODULUS(pModEngine);
int orderLen = MOD_LEN(pModEngine);
/* test input message value */
IPP_BADARG_RET(0<=cpCmp_BNU(BN_NUMBER(pMsgDigest), BN_SIZE(pMsgDigest), pOrder, orderLen), ippStsMessageErr);
/* test signature value */
if(!cpEqu_BNU_CHUNK(BN_NUMBER(pSignX), BN_SIZE(pSignX), 0) &&
!cpEqu_BNU_CHUNK(BN_NUMBER(pSignY), BN_SIZE(pSignY), 0) &&
0>cpCmp_BNU(BN_NUMBER(pSignX), BN_SIZE(pSignX), pOrder, orderLen) &&
0>cpCmp_BNU(BN_NUMBER(pSignY), BN_SIZE(pSignY), pOrder, orderLen)) {
IppsGFpState* pGF = ECP_GFP(pEC);
gsModEngine* pGFE = GFP_PMA(pGF);
int elmLen = GFP_FELEN(pGFE);
int pelmLen = GFP_PELEN(pGFE);
BNU_CHUNK_T* h1 = cpGFpGetPool(2, pGFE);
BNU_CHUNK_T* h2 = h1+pelmLen;
IppsGFpECPoint P, G, Public;
/* Y = 1/signY mod order */
__ALIGN8 IppsBigNumState Y;
__ALIGN8 IppsBigNumState R;
BNU_CHUNK_T* buffer = ECP_SBUFFER(pEC);
BN_Make(buffer, buffer+orderLen+1, orderLen, &Y);
BN_Make(buffer+(orderLen+1)*2, buffer+(orderLen+1)*3, orderLen, &R);
/* BN(order) */
BN_Set(pOrder, orderLen, &R);
ippsModInv_BN((IppsBigNumState*)pSignY, &R, &Y);
/* h1 = 1/signY mod order */
cpGFpElementCopyPadd(h1, orderLen, BN_NUMBER(&Y), BN_SIZE(&Y));
cpMontEnc_BNU_EX(h1, h1, orderLen, pModEngine);
/* validate signature */
cpEcGFpInitPoint(&P, cpEcGFpGetPool(1, pEC),0, pEC);
cpEcGFpInitPoint(&G, ECP_G(pEC), ECP_AFFINE_POINT|ECP_FINITE_POINT, pEC);
cpEcGFpInitPoint(&Public, ECP_PUBLIC(pEC), ECP_FINITE_POINT, pEC);
/* h2 = pSignX * h1 (mod order) */
cpMontMul_BNU_EX(h2,
h1,orderLen, BN_NUMBER(pSignX), BN_SIZE(pSignX),
pModEngine);
/* h1 = pMsgDigest * h1 (mod order) */
cpMontMul_BNU_EX(h1,
h1,orderLen, BN_NUMBER(pMsgDigest), BN_SIZE(pMsgDigest),
pModEngine);
/* compute h1*BasePoint + h2*publicKey */
//gfec_PointProduct(&P,
// &G, h1, orderLen, &Public, h2, orderLen,
// pEC, (Ipp8u*)ECP_SBUFFER(pEC));
gfec_BasePointProduct(&P,
h1, orderLen, &Public, h2, orderLen,
pEC, (Ipp8u*)ECP_SBUFFER(pEC));
/* get P.X */
if(gfec_GetPoint(h1, NULL, &P, pEC)) {
/* C' = 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 make sure signX==P.X */
cpGFpElementCopyPadd(h2, orderLen, BN_NUMBER(pSignX), BN_SIZE(pSignX));
if(GFP_EQ(h1, h2, orderLen))
vResult = ippECValid;
}
cpEcGFpReleasePool(1, pEC);
cpGFpReleasePool(2, pGFE);
}
*pResult = vResult;
return ippStsNoErr;
}
}
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