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/*
//
// Purpose:
// Cryptography Primitive.
// EC over Prime Finite Field (Sign, DSA version)
//
// Contents:
// ippsECCPSignDSA()
//
//
*/
#include "owndefs.h"
#include "owncp.h"
#include "pcpeccp.h"
/*F*
// Name: ippsECCPSignDSA
//
// Purpose: Signing of message representative.
// (DSA version).
//
// Returns: Reason:
// ippStsNullPtrErr NULL == pEC
// NULL == pMsgDigest
// NULL == pPrivate
// NULL == pSignX
// NULL == pSignY
//
// ippStsContextMatchErr illegal pEC->idCtx
// illegal pMsgDigest->idCtx
// illegal pPrivate->idCtx
// illegal pSignX->idCtx
// illegal pSignY->idCtx
//
// ippStsIvalidPrivateKey 0 >= Private
// Private >= order
//
// ippStsMessageErr MsgDigest >= order
// MsgDigest < 0
//
// ippStsRangeErr not enough room for:
// signX
// signY
//
// ippStsEphemeralKeyErr (0==signX) || (0==signY)
//
// ippStsNoErr no errors
//
// Parameters:
// pMsgDigest pointer to the message representative to be signed
// pPrivate pointer to the regular private key
// pSignX,pSignY pointer to the signature
// pEC pointer to the ECCP context
//
// Note:
// - ephemeral key pair extracted from pEC and
// must be generated and before ippsECCPDSASign() usage
// - ephemeral key pair destroy before exit
//
*F*/
IPPFUN(IppStatus, ippsECCPSignDSA,(const IppsBigNumState* pMsgDigest,
const IppsBigNumState* pPrivate,
IppsBigNumState* pSignX, IppsBigNumState* pSignY,
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 private key*/
IPP_BAD_PTR1_RET(pPrivate);
pPrivate = (IppsBigNumState*)( IPP_ALIGNED_PTR(pPrivate, BN_ALIGNMENT) );
IPP_BADARG_RET(!BN_VALID_ID(pPrivate), ippStsContextMatchErr);
IPP_BADARG_RET(BN_NEGATIVE(pPrivate), ippStsIvalidPrivateKey);
/* 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 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_ROOM(pSignX)*BITSIZE(BNU_CHUNK_T)<ECP_ORDBITSIZE(pEC)), ippStsRangeErr);
IPP_BADARG_RET((BN_ROOM(pSignY)*BITSIZE(BNU_CHUNK_T)<ECP_ORDBITSIZE(pEC)), ippStsRangeErr);
{
gsModEngine* pMontR = ECP_MONT_R(pEC);
BNU_CHUNK_T* pOrder = MOD_MODULUS(pMontR);
int ordLen = MOD_LEN(pMontR);
BNU_CHUNK_T* pPriData = BN_NUMBER(pPrivate);
int priLen = BN_SIZE(pPrivate);
BNU_CHUNK_T* pMsgData = BN_NUMBER(pMsgDigest);
int msgLen = BN_SIZE(pMsgDigest);
/* make sure regular 0 < private < order */
IPP_BADARG_RET(cpEqu_BNU_CHUNK(pPriData, priLen, 0) ||
0<=cpCmp_BNU(pPriData, priLen, pOrder, ordLen), ippStsIvalidPrivateKey);
/* make sure msg <order */
IPP_BADARG_RET(0<=cpCmp_BNU(pMsgData, msgLen, pOrder, ordLen), ippStsMessageErr);
{
IppsGFpState* pGF = ECP_GFP(pEC);
gsModEngine* pMontP = GFP_PMA(pGF);
int elmLen = GFP_FELEN(pMontP);
BNU_CHUNK_T* dataC = BN_NUMBER(pSignX);
BNU_CHUNK_T* dataD = BN_NUMBER(pSignY);
BNU_CHUNK_T* buffF = BN_BUFFER(pSignX);
BNU_CHUNK_T* buffT = BN_BUFFER(pSignY);
int ns;
/* ephemeral public */
IppsGFpECPoint ephPublic;
cpEcGFpInitPoint(&ephPublic, ECP_PUBLIC_E(pEC), ECP_FINITE_POINT|ECP_AFFINE_POINT, pEC);
/*
// signX = 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);
}
if(!GFP_IS_ZERO(dataC, ordLen)) {
/*
// signY = (1/ephPrivate)*(pMsgDigest + private*signX) (mod order)
*/
/* copy and expand message is being signed */
ZEXPAND_COPY_BNU(buffF, ordLen, pMsgData, msgLen);
/* 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 */
gs_mont_inv(buffT, ECP_PRIVAT_E(pEC), pMontR, alm_mont_inv_ct);
/* (1/ephPrivate)*(pMsgDigest + private*signX) */
GFP_METHOD(pMontR)->mul(dataD, dataD, buffT, pMontR);
/* signX */
ns = ordLen;
FIX_BNU(dataC, ns);
BN_SIGN(pSignX) = ippBigNumPOS;
BN_SIZE(pSignX) = ns;
/* signY */
ns = ordLen;
FIX_BNU(dataD, ns);
BN_SIGN(pSignY) = ippBigNumPOS;
BN_SIZE(pSignY) = ns;
return ippStsNoErr;
}
}
return ippStsEphemeralKeyErr;
}
}
}