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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 == pEC // NULL == pMsgDigest // NULL == pSignX // NULL == pSignY // NULL == pResult // // ippStsContextMatchErr illegal pEC->idCtx // illegal pMsgDigest->idCtx // illegal pSignX->idCtx // illegal pSignY->idCtx // // ippStsMessageErr MsgDigest >= order // MsgDigest < 0 // // ippStsRangeErr SignX < 0 or SignY < 0 // // 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 // pEC 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_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; } }