/* * Generate message signature */ void ed25519_SignMessage( unsigned char *signature, /* OUT: [64 bytes] signature (R,S) */ const unsigned char *privKey, /* IN: [64 bytes] private key (sk,pk) */ const void *blinding, /* IN: [optional] null or blinding context */ const unsigned char *msg, /* IN: [msg_size bytes] message to sign */ size_t msg_size) { SHA512_CTX H; Affine_POINT R; U_WORD a[K_WORDS], t[K_WORDS], r[K_WORDS]; U8 md[SHA512_DIGEST_LENGTH]; /* [a:b] = H(sk) */ SHA512_Init(&H); SHA512_Update(&H, privKey, 32); SHA512_Final(md, &H); ecp_TrimSecretKey(md); /* a = first 32 bytes */ ecp_BytesToWords(a, md); /* r = H(b + m) mod BPO */ SHA512_Init(&H); SHA512_Update(&H, md+32, 32); SHA512_Update(&H, msg, msg_size); SHA512_Final(md, &H); eco_DigestToWords(r, md); eco_Mod(r); /* r mod BPO */ /* R = r*P */ edp_BasePointMultiply(&R, r, blinding); ed25519_PackPoint(signature, R.y, R.x[0]); /* R part of signature */ /* S = r + H(encoded(R) + pk + m) * a mod BPO */ SHA512_Init(&H); SHA512_Update(&H, signature, 32); /* encoded(R) */ SHA512_Update(&H, privKey+32, 32); /* pk */ SHA512_Update(&H, msg, msg_size); /* m */ SHA512_Final(md, &H); eco_DigestToWords(t, md); eco_MulReduce(t, t, a); /* h()*a */ eco_AddReduce(t, t, r); eco_Mod(t); ecp_WordsToBytes(signature+32, t); /* S part of signature */ /* Clear sensitive data */ ecp_SetValue(a, 0); ecp_SetValue(r, 0); }
int curve25519_SelfTest(int level) { int rc = 0; U64 A[4], B[4], C[4]; U8 a[32], b[32], c[32], d[32]; ecp_AddReduce(A, _w_I, _w_P); ECP_MOD(A); if (ecp_Cmp(A, _w_I) != 0) { rc++; printf("assert I+p == I mod p FAILED!!\n"); ecp_PrintHexWords("A_1", A, 4); } if (ecp_Cmp(_w_I, _w_P) >= 0) { rc++; printf("assert I < P FAILED!!\n"); } if (ecp_Cmp(_w_P, _w_I) <= 0) { rc++; printf("assert P > I FAILED!!\n"); } ecp_MulReduce(B, _w_I, _w_D); ECP_MOD(B); if (ecp_Cmp(B, _w_IxD) != 0) { rc++; printf("assert I*D FAILED!!\n"); ecp_PrintHexWords("A_2", B, 4); } // assert I*I == p-1 ecp_MulMod(A, _w_I, _w_I); if (ecp_Cmp(A, _w_Pm1) != 0) { rc++; printf("assert mul(I,I) == p-1 FAILED!!\n"); ecp_PrintHexWords("A_3", A, 4); } // assert I**2 == p-1 ecp_SqrReduce(B, _w_I); ECP_MOD(B); if (ecp_Cmp(B, _w_Pm1) != 0) { rc++; printf("assert square(I) == p-1 FAILED!!\n"); ecp_PrintHexWords("B_4", B, 4); } // assert (-I)*(-I) == p-1 ecp_Sub(B, _w_P, _w_I); ecp_MulMod(A, B, B); if (ecp_Cmp(A, _w_Pm1) != 0) { rc++; printf("assert mul(-I,-I) == p-1 FAILED!!\n"); ecp_PrintHexWords("A_5", A, 4); ecp_PrintHexWords("B_5", B, 4); } ecp_SetValue(A, 50153); ecp_Inverse(B, A); ecp_MulMod(A, A, B); if (ecp_Cmp(A, _w_One) != 0) { rc++; printf("invmod FAILED!!\n"); ecp_PrintHexWords("inv_50153", B, 4); ecp_PrintHexWords("expected_1", A, 4); } // assert expmod(d,(p-1)/2,p) == p-1 ecp_ExpMod(A, _w_D, _b_Pm1d2, 32); if (ecp_Cmp(A, _w_Pm1) != 0) { rc++; printf("assert expmod(d,(p-1)/2,p) == p-1 FAILED!!\n"); ecp_PrintHexWords("A_3", A, 4); } ecp_CalculateY(a, ecp_BasePoint); ecp_BytesToWords(A, a); if (ecp_Cmp(A, _w_Gy) != 0) { rc++; printf("assert clacY(Base) == Base.y FAILED!!\n"); ecp_PrintHexBytes("Calculated_Base.y", a, 32); } ecp_PointMultiply(a, ecp_BasePoint, _b_Om1, 32); if (memcmp(a, ecp_BasePoint, 32) != 0) { rc++; printf("assert (l-1).Base == Base FAILED!!\n"); ecp_PrintHexBytes("A_5", a, 32); } ecp_PointMultiply(a, ecp_BasePoint, _b_O, 32); ecp_BytesToWords(A, a); if (!ecp_IsZero(A)) { rc++; printf("assert l.Base == 0 FAILED!!\n"); ecp_PrintHexBytes("A_6", a, 32); } // Key generation ecp_PointMultiply(a, ecp_BasePoint, pk1, 32); ecp_PrintHexBytes("PublicKey1", a, 32); ecp_PointMultiply(b, ecp_BasePoint, pk2, 32); ecp_PrintHexBytes("PublicKey2", b, 32); // ECDH - key exchange ecp_PointMultiply(c, b, pk1, 32); ecp_PrintHexBytes("SharedKey1", c, 32); ecp_PointMultiply(d, a, pk2, 32); ecp_PrintHexBytes("SharedKey2", d, 32); if (memcmp(c, d, 32) != 0) { rc++; printf("ECDH key exchange FAILED!!\n"); } memset(a, 0x44, 32); // our secret key ecp_PointMultiply(b, ecp_BasePoint, a, 32); // public key ecp_PointMultiply(c, b, _b_k1, 32); ecp_PointMultiply(d, c, _b_k2, 32); if (memcmp(d, b, 32) != 0) { rc++; printf("assert k1.k2.D == D FAILED!!\n"); ecp_PrintHexBytes("D", d, 4); ecp_PrintHexBytes("C", c, 4); ecp_PrintHexBytes("A", a, 4); } ecp_BytesToWords(A, _b_k1); ecp_BytesToWords(B, _b_k2); eco_InvModBPO(C, A); if (ecp_Cmp(C, B) != 0) { rc++; printf("assert 1/k1 == k2 mod BPO FAILED!!\n"); ecp_PrintHexWords("Calc", C, 4); ecp_PrintHexWords("Expt", B, 4); } eco_MulMod(C, A, B); if (ecp_Cmp(C, _w_One) != 0) { rc++; printf("assert k1*k2 == 1 mod BPO FAILED!!\n"); ecp_PrintHexWords("Calc", C, 4); } return rc; }