secp256k1-zkp/src/modules/recovery/tests_impl.h

/**********************************************************************
 * Copyright (c) 2013-2015 Pieter Wuille                              *
 * Distributed under the MIT software license, see the accompanying   *
 * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
 **********************************************************************/

#ifndef _SECP256K1_MODULE_RECOVERY_TESTS_
#define _SECP256K1_MODULE_RECOVERY_TESTS_

void test_ecdsa_recovery_end_to_end(void) {
    unsigned char extra[32] = {0x00};
    unsigned char privkey[32];
    unsigned char message[32];
    secp256k1_ecdsa_signature signature[5];
    secp256k1_ecdsa_recoverable_signature rsignature[5];
    unsigned char sig[74];
    secp256k1_pubkey pubkey;
    secp256k1_pubkey recpubkey;
    int recid = 0;

    /* Generate a random key and message. */
    {
        secp256k1_scalar msg, key;
        random_scalar_order_test(&msg);
        random_scalar_order_test(&key);
        secp256k1_scalar_get_b32(privkey, &key);
        secp256k1_scalar_get_b32(message, &msg);
    }

    /* Construct and verify corresponding public key. */
    CHECK(secp256k1_ec_seckey_verify(ctx, privkey) == 1);
    CHECK(secp256k1_ec_pubkey_create(ctx, &pubkey, privkey) == 1);

    /* Serialize/parse compact and verify/recover. */
    extra[0] = 0;
    CHECK(secp256k1_ecdsa_sign_recoverable(ctx, &rsignature[0], message, privkey, NULL, NULL) == 1);
    CHECK(secp256k1_ecdsa_sign_recoverable(ctx, &rsignature[4], message, privkey, NULL, NULL) == 1);
    CHECK(secp256k1_ecdsa_sign_recoverable(ctx, &rsignature[1], message, privkey, NULL, extra) == 1);
    extra[31] = 1;
    CHECK(secp256k1_ecdsa_sign_recoverable(ctx, &rsignature[2], message, privkey, NULL, extra) == 1);
    extra[31] = 0;
    extra[0] = 1;
    CHECK(secp256k1_ecdsa_sign_recoverable(ctx, &rsignature[3], message, privkey, NULL, extra) == 1);
    CHECK(secp256k1_ecdsa_recoverable_signature_serialize_compact(ctx, sig, &recid, &rsignature[4]) == 1);
    CHECK(secp256k1_ecdsa_recoverable_signature_convert(ctx, &signature[4], &rsignature[4]) == 1);
    CHECK(secp256k1_ecdsa_verify(ctx, &signature[4], message, &pubkey) == 1);
    memset(&rsignature[4], 0, sizeof(rsignature[4]));
    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsignature[4], sig, recid) == 1);
    CHECK(secp256k1_ecdsa_recoverable_signature_convert(ctx, &signature[4], &rsignature[4]) == 1);
    CHECK(secp256k1_ecdsa_verify(ctx, &signature[4], message, &pubkey) == 1);
    /* Parse compact (with recovery id) and recover. */
    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsignature[4], sig, recid) == 1);
    CHECK(secp256k1_ecdsa_recover(ctx, &recpubkey, &rsignature[4], message) == 1);
    CHECK(memcmp(&pubkey, &recpubkey, sizeof(pubkey)) == 0);
    /* Serialize/destroy/parse signature and verify again. */
    CHECK(secp256k1_ecdsa_recoverable_signature_serialize_compact(ctx, sig, &recid, &rsignature[4]) == 1);
    sig[secp256k1_rand32() % 64] += 1 + (secp256k1_rand32() % 255);
    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsignature[4], sig, recid) == 1);
    CHECK(secp256k1_ecdsa_recoverable_signature_convert(ctx, &signature[4], &rsignature[4]) == 1);
    CHECK(secp256k1_ecdsa_verify(ctx, &signature[4], message, &pubkey) == 0);
    /* Recover again */
    CHECK(secp256k1_ecdsa_recover(ctx, &recpubkey, &rsignature[4], message) == 0 ||
          memcmp(&pubkey, &recpubkey, sizeof(pubkey)) != 0);
}

/* Tests several edge cases. */
void test_ecdsa_recovery_edge_cases(void) {
    const unsigned char msg32[32] = {
        'T', 'h', 'i', 's', ' ', 'i', 's', ' ',
        'a', ' ', 'v', 'e', 'r', 'y', ' ', 's',
        'e', 'c', 'r', 'e', 't', ' ', 'm', 'e',
        's', 's', 'a', 'g', 'e', '.', '.', '.'
    };
    const unsigned char sig64[64] = {
        /* Generated by signing the above message with nonce 'This is the nonce we will use...'
         * and secret key 0 (which is not valid), resulting in recid 0. */
        0x67, 0xCB, 0x28, 0x5F, 0x9C, 0xD1, 0x94, 0xE8,
        0x40, 0xD6, 0x29, 0x39, 0x7A, 0xF5, 0x56, 0x96,
        0x62, 0xFD, 0xE4, 0x46, 0x49, 0x99, 0x59, 0x63,
        0x17, 0x9A, 0x7D, 0xD1, 0x7B, 0xD2, 0x35, 0x32,
        0x4B, 0x1B, 0x7D, 0xF3, 0x4C, 0xE1, 0xF6, 0x8E,
        0x69, 0x4F, 0xF6, 0xF1, 0x1A, 0xC7, 0x51, 0xDD,
        0x7D, 0xD7, 0x3E, 0x38, 0x7E, 0xE4, 0xFC, 0x86,
        0x6E, 0x1B, 0xE8, 0xEC, 0xC7, 0xDD, 0x95, 0x57
    };
    secp256k1_pubkey pubkey;
    /* signature (r,s) = (4,4), which can be recovered with all 4 recids. */
    const unsigned char sigb64[64] = {
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04,
    };
    secp256k1_pubkey pubkeyb;
    secp256k1_ecdsa_recoverable_signature rsig;
    secp256k1_ecdsa_signature sig;
    int recid;

    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sig64, 0));
    CHECK(!secp256k1_ecdsa_recover(ctx, &pubkey, &rsig, msg32));
    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sig64, 1));
    CHECK(secp256k1_ecdsa_recover(ctx, &pubkey, &rsig, msg32));
    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sig64, 2));
    CHECK(!secp256k1_ecdsa_recover(ctx, &pubkey, &rsig, msg32));
    CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sig64, 3));
    CHECK(!secp256k1_ecdsa_recover(ctx, &pubkey, &rsig, msg32));

    for (recid = 0; recid < 4; recid++) {
        int i;
        int recid2;
        /* (4,4) encoded in DER. */
        unsigned char sigbder[8] = {0x30, 0x06, 0x02, 0x01, 0x04, 0x02, 0x01, 0x04};
        unsigned char sigcder_zr[7] = {0x30, 0x05, 0x02, 0x00, 0x02, 0x01, 0x01};
        unsigned char sigcder_zs[7] = {0x30, 0x05, 0x02, 0x01, 0x01, 0x02, 0x00};
        unsigned char sigbderalt1[39] = {
            0x30, 0x25, 0x02, 0x20, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x04, 0x02, 0x01, 0x04,
        };
        unsigned char sigbderalt2[39] = {
            0x30, 0x25, 0x02, 0x01, 0x04, 0x02, 0x20, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04,
        };
        unsigned char sigbderalt3[40] = {
            0x30, 0x26, 0x02, 0x21, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x04, 0x02, 0x01, 0x04,
        };
        unsigned char sigbderalt4[40] = {
            0x30, 0x26, 0x02, 0x01, 0x04, 0x02, 0x21, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04,
        };
        /* (order + r,4) encoded in DER. */
        unsigned char sigbderlong[40] = {
            0x30, 0x26, 0x02, 0x21, 0x00, 0xFF, 0xFF, 0xFF,
            0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
            0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xBA, 0xAE, 0xDC,
            0xE6, 0xAF, 0x48, 0xA0, 0x3B, 0xBF, 0xD2, 0x5E,
            0x8C, 0xD0, 0x36, 0x41, 0x45, 0x02, 0x01, 0x04
        };
        CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sigb64, recid) == 1);
        CHECK(secp256k1_ecdsa_recover(ctx, &pubkeyb, &rsig, msg32) == 1);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbder, sizeof(sigbder)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 1);
        for (recid2 = 0; recid2 < 4; recid2++) {
            secp256k1_pubkey pubkey2b;
            CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sigb64, recid2) == 1);
            CHECK(secp256k1_ecdsa_recover(ctx, &pubkey2b, &rsig, msg32) == 1);
            /* Verifying with (order + r,4) should always fail. */
            CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderlong, sizeof(sigbderlong)) == 0);
        }
        /* DER parsing tests. */
        /* Zero length r/s. */
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigcder_zr, sizeof(sigcder_zr)) == 0);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigcder_zs, sizeof(sigcder_zs)) == 0);
        /* Leading zeros. */
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderalt1, sizeof(sigbderalt1)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 1);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderalt2, sizeof(sigbderalt2)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 1);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderalt3, sizeof(sigbderalt3)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 1);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderalt4, sizeof(sigbderalt4)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 1);
        sigbderalt3[4] = 1;
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderalt3, sizeof(sigbderalt3)) == 0);
        sigbderalt4[7] = 1;
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbderalt4, sizeof(sigbderalt4)) == 0);
        /* Damage signature. */
        sigbder[7]++;
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbder, sizeof(sigbder)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 0);
        sigbder[7]--;
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbder, 6) == 0);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbder, sizeof(sigbder) - 1) == 0);
        for(i = 0; i < 8; i++) {
            int c;
            unsigned char orig = sigbder[i];
            /*Try every single-byte change.*/
            for (c = 0; c < 256; c++) {
                if (c == orig ) {
                    continue;
                }
                sigbder[i] = c;
                CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigbder, sizeof(sigbder)) == 0 || secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyb) == 0);
            }
            sigbder[i] = orig;
        }
    }

    /* Test r/s equal to zero */
    {
        /* (1,1) encoded in DER. */
        unsigned char sigcder[8] = {0x30, 0x06, 0x02, 0x01, 0x01, 0x02, 0x01, 0x01};
        unsigned char sigc64[64] = {
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
        };
        secp256k1_pubkey pubkeyc;
        CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sigc64, 0) == 1);
        CHECK(secp256k1_ecdsa_recover(ctx, &pubkeyc, &rsig, msg32) == 1);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigcder, sizeof(sigcder)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyc) == 1);
        sigcder[4] = 0;
        sigc64[31] = 0;
        CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sigc64, 0) == 1);
        CHECK(secp256k1_ecdsa_recover(ctx, &pubkeyb, &rsig, msg32) == 0);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigcder, sizeof(sigcder)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyc) == 0);
        sigcder[4] = 1;
        sigcder[7] = 0;
        sigc64[31] = 1;
        sigc64[63] = 0;
        CHECK(secp256k1_ecdsa_recoverable_signature_parse_compact(ctx, &rsig, sigc64, 0) == 1);
        CHECK(secp256k1_ecdsa_recover(ctx, &pubkeyb, &rsig, msg32) == 0);
        CHECK(secp256k1_ecdsa_signature_parse_der(ctx, &sig, sigcder, sizeof(sigcder)) == 1);
        CHECK(secp256k1_ecdsa_verify(ctx, &sig, msg32, &pubkeyc) == 0);
    }
}

void run_recovery_tests(void) {
    int i;
    for (i = 0; i < 64*count; i++) {
        test_ecdsa_recovery_end_to_end();
    }
    test_ecdsa_recovery_edge_cases();
}

#endif