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/*
// Intel(R) Integrated Performance Primitives. Cryptography Primitives.
//
// Context:
// ippsGFpECSignDSA()
//
*/
#include "owndefs.h"
#include "owncp.h"
#include "pcpeccp.h"
/*F*
// Name: ippsGFpECSignDSA
//
// Purpose: DSA Signature Generation.
//
// Returns: Reason:
// ippStsNullPtrErr NULL == pEC
// NULL == pMsgDigest
// NULL == pRegPrivate
// NULL == pEphPrivate
// NULL == pSignR
// NULL == pSignS
// NULL == pScratchBuffer
//
// ippStsContextMatchErr illegal pEC->idCtx
// pEC->subgroup == NULL
// illegal pMsgDigest->idCtx
// illegal pRegPrivate->idCtx
// illegal pEphPrivate->idCtx
// illegal pSignR->idCtx
// illegal pSignS->idCtx
//
// ippStsIvalidPrivateKey 0 >= RegPrivate
// RegPrivate >= order
//
// 0 >= EphPrivate
// EphPrivate >= order
//
// ippStsMessageErr MsgDigest >= order
// MsgDigest < 0
//
// ippStsRangeErr not enough room for:
// signR
// signS
//
// ippStsEphemeralKeyErr (0==signR) || (0==signS)
//
// ippStsNotSupportedModeErr pGFE->extdegree > 1
//
//
// ippStsNoErr no errors
//
// Parameters:
// pMsgDigest pointer to the message representative to be signed
// pRegPrivate pointer to the regular private key
// pEphPrivate pointer to the ephemeral private key
// pSignR,pSignS pointer to the signature
// pEC pointer to the EC context
// pScratchBuffer pointer to buffer (1 mul_point operation)
//
*F*/
IPPFUN(IppStatus, ippsGFpECSignDSA,(const IppsBigNumState* pMsgDigest,
const IppsBigNumState* pRegPrivate,
const IppsBigNumState* pEphPrivate,
IppsBigNumState* pSignR, IppsBigNumState* pSignS,
IppsGFpECState* pEC,
Ipp8u* pScratchBuffer))
{
IppsGFpState* pGF;
gsModEngine* pMontP;
/* 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);
pMontP = GFP_PMA(pGF);
IPP_BADARG_RET(1<GFP_EXTDEGREE(pMontP), 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 signature */
IPP_BAD_PTR2_RET(pSignR, pSignS);
pSignR = (IppsBigNumState*)( IPP_ALIGNED_PTR(pSignR, BN_ALIGNMENT) );
pSignS = (IppsBigNumState*)( IPP_ALIGNED_PTR(pSignS, BN_ALIGNMENT) );
IPP_BADARG_RET(!BN_VALID_ID(pSignR), ippStsContextMatchErr);
IPP_BADARG_RET(!BN_VALID_ID(pSignS), ippStsContextMatchErr);
IPP_BADARG_RET((BN_ROOM(pSignR)*BITSIZE(BNU_CHUNK_T)<ECP_ORDBITSIZE(pEC)), ippStsRangeErr);
IPP_BADARG_RET((BN_ROOM(pSignS)*BITSIZE(BNU_CHUNK_T)<ECP_ORDBITSIZE(pEC)), ippStsRangeErr);
/* test private keys */
IPP_BAD_PTR2_RET(pRegPrivate, pEphPrivate);
pRegPrivate = (IppsBigNumState*)( IPP_ALIGNED_PTR(pRegPrivate, ALIGN_VAL) );
IPP_BADARG_RET(!BN_VALID_ID(pRegPrivate), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pRegPrivate), ippStsIvalidPrivateKey);
pEphPrivate = (IppsBigNumState*)( IPP_ALIGNED_PTR(pEphPrivate, ALIGN_VAL) );
IPP_BADARG_RET(!BN_VALID_ID(pEphPrivate), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pEphPrivate), ippStsEphemeralKeyErr);
{
gsModEngine* pMontR = ECP_MONT_R(pEC);
BNU_CHUNK_T* pOrder = MOD_MODULUS(pMontR);
int ordLen = MOD_LEN(pMontR);
BNU_CHUNK_T* dataC = BN_NUMBER(pSignR);
BNU_CHUNK_T* dataD = BN_NUMBER(pSignS);
BNU_CHUNK_T* buffF = BN_BUFFER(pSignR);
BNU_CHUNK_T* buffT = BN_BUFFER(pSignS);
BNU_CHUNK_T* pPriData = BN_NUMBER(pRegPrivate);
int priLen = BN_SIZE(pRegPrivate);
BNU_CHUNK_T* pEphData = BN_NUMBER(pEphPrivate);
int ephLen = BN_SIZE(pEphPrivate);
BNU_CHUNK_T* pMsgData = BN_NUMBER(pMsgDigest);
int msgLen = BN_SIZE(pMsgDigest);
/* test value of private keys: 0 < regPrivate < order, 0 < ephPrivate < order */
IPP_BADARG_RET(cpEqu_BNU_CHUNK(pPriData, priLen, 0) ||
0<=cpCmp_BNU(pPriData, priLen, pOrder, ordLen), ippStsIvalidPrivateKey);
IPP_BADARG_RET(cpEqu_BNU_CHUNK(pEphData, ephLen, 0) ||
0<=cpCmp_BNU(pEphData, ephLen, pOrder, ordLen), ippStsEphemeralKeyErr);
/* make sure msg <order */
IPP_BADARG_RET(0<=cpCmp_BNU(pMsgData, msgLen, pOrder, ordLen), ippStsMessageErr);
{
int elmLen = GFP_FELEN(pMontP);
int ns;
/* compute ephemeral public key */
IppsGFpECPoint ephPublic;
cpEcGFpInitPoint(&ephPublic, cpEcGFpGetPool(1, pEC), 0, pEC);
gfec_MulBasePoint(&ephPublic,
BN_NUMBER(pEphPrivate), BN_SIZE(pEphPrivate),
pEC, pScratchBuffer);
/*
// signR = int(ephPublic.x) (mod order)
*/
{
BNU_CHUNK_T* buffer = gsModPoolAlloc(pMontP, 1);
gfec_GetPoint(buffer, NULL, &ephPublic, pEC);
GFP_METHOD(pMontP)->decode(buffer, buffer, pMontP);
ns = cpMod_BNU(buffer, elmLen, pOrder, ordLen);
cpGFpElementCopyPadd(dataC, ordLen, buffer, ns);
gsModPoolFree(pMontP, 1);
}
cpEcGFpReleasePool(1, pEC);
if(!GFP_IS_ZERO(dataC, ordLen)) {
/*
// signS = (1/ephPrivate)*(pMsgDigest + private*signR) (mod order)
*/
/* reduce message: msg = msg mod ordfer */
BNU_CHUNK_T* buffMsg= BN_BUFFER(pMsgDigest);
COPY_BNU(buffMsg, pMsgData, msgLen);
ns = cpMod_BNU(buffMsg, msgLen, pOrder, ordLen);
/* copy and expand message is being signed */
ZEXPAND_COPY_BNU(buffF, ordLen, buffMsg, ns);
/* private representation in Montgomery domain */
ZEXPAND_COPY_BNU(dataD, ordLen, pPriData, priLen);
GFP_METHOD(pMontR)->encode(dataD, dataD, pMontR);
/* (private*signX) in regular domain */
GFP_METHOD(pMontR)->mul(dataD, dataD, dataC, pMontR);
/* pMsgDigest + private*signX */
cpModAdd_BNU(dataD, dataD, buffF, pOrder, ordLen, buffT);
if(!GFP_IS_ZERO(dataD, ordLen)) {
/* (1/ephPrivate) in Montgomery domain */
ZEXPAND_COPY_BNU(buffT, ordLen, pEphData, ephLen);
gs_mont_inv(buffT, buffT, pMontR, alm_mont_inv_ct);
/* (1/ephPrivate)*(pMsgDigest + private*signS) */
GFP_METHOD(pMontR)->mul(dataD, dataD, buffT, pMontR);
/* signR */
ns = ordLen;
FIX_BNU(dataC, ns);
BN_SIGN(pSignR) = ippBigNumPOS;
BN_SIZE(pSignR) = ns;
/* signS */
ns = ordLen;
FIX_BNU(dataD, ns);
BN_SIGN(pSignS) = ippBigNumPOS;
BN_SIZE(pSignS) = ns;
return ippStsNoErr;
}
}
return ippStsEphemeralKeyErr;
}
}
}