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You may 30 * obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 31 * 32 * 33 * Unless required by applicable law or agreed to in writing, software 34 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 35 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 36 * 37 * See the License for the specific language governing permissions and 38 * limitations under the License. 39 *******************************************************************************/ 40 41 /* 42 // Intel(R) Integrated Performance Primitives. Cryptography Primitives. 43 // EC over GF(p^m) definitinons 44 // 45 // Context: 46 // ippsGFpECVerify() 47 // 48 */ 49 50 #include "owndefs.h" 51 #include "owncp.h" 52 #include "pcpgfpecstuff.h" 53 #include "pcpeccp.h" 54 55 //tbcd: temporary excluded: #include <assert.h> 56 /*F* 57 // Name: ippsGFpECVerify 58 // 59 // Purpose: Verifies the parameters of an elliptic curve. 60 // 61 // Returns: Reason: 62 // ippStsNullPtrErr pEC == NULL 63 // pResult == NULL 64 // pScratchBuffer == NULL 65 // ippStsContextMatchErr invalid pEC->idCtx 66 // ippStsNoErr no error 67 // 68 // Parameters: 69 // pResult Pointer to the verification result 70 // pEC Pointer to the context of the elliptic curve 71 // pScratchBuffer Pointer to the scratch buffer 72 // 73 *F*/ 74 75 IPPFUN(IppStatus, ippsGFpECVerify,(IppECResult* pResult, IppsGFpECState* pEC, Ipp8u* pScratchBuffer)) 76 { 77 IPP_BAD_PTR3_RET(pEC, pResult, pScratchBuffer); 78 pEC = (IppsGFpECState*)( IPP_ALIGNED_PTR(pEC, ECGFP_ALIGNMENT) ); 79 IPP_BADARG_RET( !ECP_TEST_ID(pEC), ippStsContextMatchErr ); 80 81 *pResult = ippECValid; 82 83 { 84 IppsGFpState* pGF = ECP_GFP(pEC); 85 gsModEngine* pGFE = GFP_PMA(pGF); 86 int elemLen = GFP_FELEN(pGFE); 87 88 mod_mul mulF = GFP_METHOD(pGFE)->mul; 89 mod_sqr sqrF = GFP_METHOD(pGFE)->sqr; 90 mod_add addF = GFP_METHOD(pGFE)->add; 91 92 /* 93 // check discriminant ( 4*A^3 + 27*B^2 != 0 mod P) 94 */ 95 if(ippECValid == *pResult) { 96 BNU_CHUNK_T* pT = cpGFpGetPool(1, pGFE); 97 BNU_CHUNK_T* pU = cpGFpGetPool(1, pGFE); 98 //tbcd: temporary excluded: assert(NULL!=pT && NULL!=pU); 99 100 if(ECP_SPECIFIC(pEC)==ECP_EPID2) 101 cpGFpElementPadd(pT, elemLen, 0); /* T = 4*A^3 = 0 */ 102 else { 103 addF(pT, ECP_A(pEC), ECP_A(pEC), pGFE); /* T = 4*A^3 */ 104 sqrF(pT, pT, pGFE); 105 mulF(pT, ECP_A(pEC), pT, pGFE); 106 } 107 108 addF(pU, ECP_B(pEC), ECP_B(pEC), pGFE); /* U = 9*B^2 */ 109 addF(pU, pU, ECP_B(pEC), pGFE); 110 sqrF(pU, pU, pGFE); 111 112 addF(pT, pU, pT, pGFE); /* T += 3*U */ 113 addF(pT, pU, pT, pGFE); 114 addF(pT, pU, pT, pGFE); 115 116 *pResult = GFP_IS_ZERO(pT, elemLen)? ippECIsZeroDiscriminant: ippECValid; 117 118 cpGFpReleasePool(2, pGFE); 119 } 120 121 if(ECP_SUBGROUP(pEC)) { 122 /* 123 // check base point and it order 124 */ 125 if(ippECValid == *pResult) { 126 IppsGFpECPoint G; 127 cpEcGFpInitPoint(&G, ECP_G(pEC), ECP_AFFINE_POINT|ECP_FINITE_POINT, pEC); 128 129 /* check G != infinity */ 130 *pResult = gfec_IsPointAtInfinity(&G)? ippECPointIsAtInfinite : ippECValid; 131 132 /* check G lies on EC */ 133 if(ippECValid == *pResult) 134 *pResult = gfec_IsPointOnCurve(&G, pEC)? ippECValid : ippECPointIsNotValid; 135 136 /* check Gorder*G = infinity */ 137 if(ippECValid == *pResult) { 138 IppsGFpECPoint T; 139 cpEcGFpInitPoint(&T, cpEcGFpGetPool(1, pEC),0, pEC); 140 141 gfec_MulBasePoint(&T, MOD_MODULUS(ECP_MONT_R(pEC)), BITS_BNU_CHUNK(ECP_ORDBITSIZE(pEC)), pEC, pScratchBuffer); 142 143 *pResult = gfec_IsPointAtInfinity(&T)? ippECValid : ippECInvalidOrder; 144 145 cpEcGFpReleasePool(1, pEC); 146 } 147 } 148 149 /* 150 // check order==P 151 */ 152 if(ippECValid == *pResult) { 153 BNU_CHUNK_T* pPrime = GFP_MODULUS(pGFE); 154 int primeLen = GFP_FELEN(pGFE); 155 156 gsModEngine* pR = ECP_MONT_R(pEC); 157 BNU_CHUNK_T* pOrder = MOD_MODULUS(pR); 158 int orderLen = MOD_LEN(pR); 159 160 *pResult = (primeLen==orderLen && GFP_EQ(pPrime, pOrder, primeLen))? ippECIsWeakSSSA : ippECValid; 161 } 162 } 163 164 return ippStsNoErr; 165 } 166 } 167