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Stable release v32.1bitcoin/bitcoin · f0de87f04062 ↗3,020 source files · 47.5 MB stored on the server440 file guides

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1/*************************************************************************
2 * Written in 2020-2022 by Elichai Turkel                                *
3 * To the extent possible under law, the author(s) have dedicated all    *
4 * copyright and related and neighboring rights to the software in this  *
5 * file to the public domain worldwide. This software is distributed     *
6 * without any warranty. For the CC0 Public Domain Dedication, see       *
7 * EXAMPLES_COPYING or https://creativecommons.org/publicdomain/zero/1.0 *
8 *************************************************************************/
9
10#include <stdio.h>
11#include <stdlib.h>
12#include <assert.h>
13#include <string.h>
14
15#include <secp256k1.h>
16
17#include "examples_util.h"
18
19int main(void) {
20    /* Instead of signing the message directly, we must sign a 32-byte hash.
21     * Here the message is "Hello, world!" and the hash function was SHA-256.
22     * An actual implementation should just call SHA-256, but this example
23     * hardcodes the output to avoid depending on an additional library.
24     * See https://bitcoin.stackexchange.com/questions/81115/if-someone-wanted-to-pretend-to-be-satoshi-by-posting-a-fake-signature-to-defrau/81116#81116 */
25    unsigned char msg_hash[32] = {
26        0x31, 0x5F, 0x5B, 0xDB, 0x76, 0xD0, 0x78, 0xC4,
27        0x3B, 0x8A, 0xC0, 0x06, 0x4E, 0x4A, 0x01, 0x64,
28        0x61, 0x2B, 0x1F, 0xCE, 0x77, 0xC8, 0x69, 0x34,
29        0x5B, 0xFC, 0x94, 0xC7, 0x58, 0x94, 0xED, 0xD3,
30    };
31    unsigned char seckey[32];
32    unsigned char randomize[32];
33    unsigned char compressed_pubkey[33];
34    unsigned char serialized_signature[64];
35    size_t len;
36    int is_signature_valid, is_signature_valid2;
37    int return_val;
38    secp256k1_pubkey pubkey;
39    secp256k1_ecdsa_signature sig;
40    /* Before we can call actual API functions, we need to create a "context". */
41    secp256k1_context* ctx = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
42    if (!fill_random(randomize, sizeof(randomize))) {
43        printf("Failed to generate randomness\n");
44        return EXIT_FAILURE;
45    }
46    /* Randomizing the context is recommended to protect against side-channel
47     * leakage See `secp256k1_context_randomize` in secp256k1.h for more
48     * information about it. This should never fail. */
49    return_val = secp256k1_context_randomize(ctx, randomize);
50    assert(return_val);
51
52    /*** Key Generation ***/
53    if (!fill_random(seckey, sizeof(seckey))) {
54        printf("Failed to generate randomness\n");
55        return EXIT_FAILURE;
56    }
57    /* If the secret key is zero or out of range (greater than secp256k1's
58    * order), we fail. Note that the probability of this occurring is negligible
59    * with a properly functioning random number generator. */
60    if (!secp256k1_ec_seckey_verify(ctx, seckey)) {
61        printf("Generated secret key is invalid. This indicates an issue with the random number generator.\n");
62        return EXIT_FAILURE;
63    }
64
65    /* Public key creation using a valid context with a verified secret key should never fail */
66    return_val = secp256k1_ec_pubkey_create(ctx, &pubkey, seckey);
67    assert(return_val);
68
69    /* Serialize the pubkey in a compressed form(33 bytes). Should always return 1. */
70    len = sizeof(compressed_pubkey);
71    return_val = secp256k1_ec_pubkey_serialize(ctx, compressed_pubkey, &len, &pubkey, SECP256K1_EC_COMPRESSED);
72    assert(return_val);
73    /* Should be the same size as the size of the output, because we passed a 33 byte array. */
74    assert(len == sizeof(compressed_pubkey));
75
76    /*** Signing ***/
77
78    /* Generate an ECDSA signature `noncefp` and `ndata` allows you to pass a
79     * custom nonce function, passing `NULL` will use the RFC-6979 safe default.
80     * Signing with a valid context, verified secret key
81     * and the default nonce function should never fail. */
82    return_val = secp256k1_ecdsa_sign(ctx, &sig, msg_hash, seckey, NULL, NULL);
83    assert(return_val);
84
85    /* Serialize the signature in a compact form. Should always return 1
86     * according to the documentation in secp256k1.h. */
87    return_val = secp256k1_ecdsa_signature_serialize_compact(ctx, serialized_signature, &sig);
88    assert(return_val);
89
90
91    /*** Verification ***/
92
93    /* Deserialize the signature. This will return 0 if the signature can't be parsed correctly. */
94    if (!secp256k1_ecdsa_signature_parse_compact(ctx, &sig, serialized_signature)) {
95        printf("Failed parsing the signature\n");
96        return EXIT_FAILURE;
97    }
98
99    /* Deserialize the public key. This will return 0 if the public key can't be parsed correctly. */
100    if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, compressed_pubkey, sizeof(compressed_pubkey))) {
101        printf("Failed parsing the public key\n");
102        return EXIT_FAILURE;
103    }
104
105    /* Verify a signature. This will return 1 if it's valid and 0 if it's not. */
106    is_signature_valid = secp256k1_ecdsa_verify(ctx, &sig, msg_hash, &pubkey);
107
108    printf("Is the signature valid? %s\n", is_signature_valid ? "true" : "false");
109    printf("Secret Key: ");
110    print_hex(seckey, sizeof(seckey));
111    printf("Public Key: ");
112    print_hex(compressed_pubkey, sizeof(compressed_pubkey));
113    printf("Signature: ");
114    print_hex(serialized_signature, sizeof(serialized_signature));
115
116    /* This will clear everything from the context and free the memory */
117    secp256k1_context_destroy(ctx);
118
119    /* Bonus example: if all we need is signature verification (and no key
120       generation or signing), we don't need to use a context created via
121       secp256k1_context_create(). We can simply use the static (i.e., global)
122       context secp256k1_context_static. See its description in
123       include/secp256k1.h for details. */
124    is_signature_valid2 = secp256k1_ecdsa_verify(secp256k1_context_static,
125                                                 &sig, msg_hash, &pubkey);
126    assert(is_signature_valid2 == is_signature_valid);
127
128    /* It's best practice to try to clear secrets from memory after using them.
129     * This is done because some bugs can allow an attacker to leak memory, for
130     * example through "out of bounds" array access (see Heartbleed), or the OS
131     * swapping them to disk. Hence, we overwrite the secret key buffer with zeros.
132     *
133     * Here we are preventing these writes from being optimized out, as any good compiler
134     * will remove any writes that aren't used. */
135    secure_erase(seckey, sizeof(seckey));
136
137    return EXIT_SUCCESS;
138}
139

src/wallet/receive.cpp

src/wallet/coinselection.cpp

src/consensus/validation.h

src/primitives/transaction.cpp

src/script/descriptor.cpp

src/bitcoin-cli.cpp

src/rpc/blockchain.cpp

src/rpc/rawtransaction.cpp

src/init.cpp

src/crypto/sha256.cpp

src/consensus/merkle.h

src/consensus/tx_check.h

src/consensus/tx_verify.h

src/policy/feerate.h

src/policy/feerate.cpp

src/primitives/transaction_identifier.h

src/chainparamsbase.h

src/chainparamsbase.cpp

src/util/moneystr.cpp

src/crypto/ripemd160.h

src/crypto/sha1.h

src/crypto/sha512.h

src/crypto/hmac_sha256.h

src/crypto/hmac_sha512.h

src/crypto/hmac_sha256.cpp

src/crypto/hmac_sha512.cpp

src/crypto/hkdf_sha256_32.h

src/crypto/hkdf_sha256_32.cpp

src/support/cleanse.h

src/support/cleanse.cpp

src/crypto/siphash.cpp

src/crypto/muhash.h

src/crypto/chacha20.h

src/crypto/poly1305.h

src/crypto/chacha20poly1305.h

src/crypto/chacha20poly1305.cpp

src/util/chaintype.cpp

src/util/obfuscation.h

src/util/byte_units.h

src/util/overflow.h

src/blockencodings.cpp

src/net_permissions.cpp

src/policy/packages.cpp

src/policy/rbf.cpp

src/policy/truc_policy.cpp

src/policy/ephemeral_policy.cpp

src/policy/settings.cpp

src/policy/policy.cpp

src/node/transaction.cpp

src/node/coin.cpp

src/rpc/client.cpp

src/rpc/external_signer.cpp

src/rpc/request.cpp

src/rpc/server_util.cpp

src/rpc/fees.cpp

src/rpc/output_script.cpp

src/rpc/rawtransaction_util.cpp

src/rpc/rawtransaction_util.h

src/rpc/register.h

src/rpc/request.h

src/rpc/server_util.h

src/rpc/protocol.h

src/rpc/server.h

src/rpc/signmessage.cpp

src/rpc/txoutproof.cpp

src/rpc/util.cpp

src/rpc/util.h

src/wallet/rpc/addresses.cpp

src/wallet/rpc/backup.cpp

src/wallet/rpc/coins.cpp

src/wallet/rpc/encrypt.cpp

src/wallet/rpc/signmessage.cpp

src/wallet/rpc/util.cpp

src/wallet/rpc/util.h

src/wallet/coincontrol.cpp

src/wallet/coincontrol.h

src/wallet/context.cpp

src/wallet/context.h

src/wallet/crypter.cpp

src/wallet/crypter.h

src/wallet/db.cpp

src/wallet/export.cpp

src/wallet/external_signer_scriptpubkeyman.cpp

src/wallet/rpc/spend.cpp

src/wallet/rpc/transactions.cpp

src/wallet/rpc/wallet.cpp

src/wallet/feebumper.cpp

src/wallet/feebumper.h

src/index/base.h

src/index/base.cpp

src/index/txindex.h

src/index/txindex.cpp

src/index/txindex_key.h

src/index/txospenderindex.h

src/index/txospenderindex.cpp

src/index/blockfilterindex.h

src/index/blockfilterindex.cpp

src/index/coinstatsindex.h

src/index/coinstatsindex.cpp

src/index/db_key.h

src/index/disktxpos.h

src/kernel/chain.cpp

src/kernel/chain.h

src/kernel/checks.cpp

src/kernel/checks.h

src/kernel/context.cpp

src/kernel/context.h

src/kernel/cs_main.cpp

src/kernel/cs_main.h

src/kernel/disconnected_transactions.cpp

src/kernel/disconnected_transactions.h

src/kernel/mempool_removal_reason.cpp

src/kernel/mempool_removal_reason.h

src/kernel/coinstats.cpp

src/kernel/coinstats.h

src/kernel/chainparams.cpp

src/kernel/chainparams.h

src/wallet/sqlite.cpp

src/wallet/sqlite.h

src/wallet/transaction.cpp

src/wallet/transaction.h

src/wallet/dump.cpp

src/wallet/dump.h

src/wallet/init.cpp

src/wallet/walletutil.cpp

src/wallet/walletutil.h

src/wallet/wallettool.cpp

src/wallet/wallettool.h

src/wallet/export.h

src/wallet/migrate.cpp

src/wallet/migrate.h

src/wallet/db.h

src/wallet/walletdb.cpp

src/wallet/interfaces.cpp

src/wallet/scriptpubkeyman.cpp

src/wallet/scriptpubkeyman.h

src/kernel/bitcoinkernel.cpp

src/kernel/bitcoinkernel.h

src/kernel/bitcoinkernel_wrapper.h

src/node/chainstate.cpp

src/node/chainstate.h

src/node/blockstorage.cpp

src/node/blockstorage.h

src/node/mempool_persist.cpp

src/node/mempool_persist.h

src/node/utxo_snapshot.cpp

src/node/utxo_snapshot.h

src/node/kernel_notifications.cpp

src/node/kernel_notifications.h

src/node/blockmanager_args.cpp

src/kernel/blockmanager_opts.h

src/util/expected.cpp

src/policy/settings.h

src/util/types.h

src/kernel/messagestartchars.h

src/kernel/warning.h

src/util/exception.h

src/common/license_info.h

src/node/coins_view_args.h

src/node/database_args.h

src/util/batchpriority.h

src/util/ui_change_type.h

src/node/coins_view_args.cpp

src/node/peerman_args.h

src/util/serfloat.h

src/node/blockmanager_args.h

src/node/database_args.cpp

src/util/overloaded.h

src/interfaces/types.h

src/node/chainstatemanager_args.h

src/node/minisketchwrapper.h

src/util/macros.h

src/util/syserror.h

src/common/run_command.h

src/util/bytevectorhash.cpp

src/node/mempool_persist_args.cpp

src/util/exec.h

src/util/rbf.h

src/crypto/hex_base.h

src/node/mempool_persist_args.h

src/interfaces/echo.h

src/util/any.h

src/util/batchpriority.cpp

src/util/threadnames.h

src/node/coin.h

src/node/mempool_args.h

src/util/asmap.h

src/util/bytevectorhash.h

src/node/context.cpp

src/util/insert.h

src/util/readwritefile.h

src/node/peerman_args.cpp

src/node/interface_ui.cpp

src/interfaces/handler.h

src/node/mining_args.h

src/util/hasher.cpp

src/common/init.h

src/kernel/mempool_limits.h

src/common/system.h

src/crypto/sha3.h

src/util/threadinterrupt.cpp

src/node/protocol_version.h

src/util/exception.cpp

src/common/messages.h

src/node/connection_types.cpp

src/util/bip32.h

src/common/license_info.cpp

src/util/stdmutex.h

src/common/run_command.cpp

src/util/check.cpp

src/util/golombrice.h

src/node/types.h

src/node/timeoffsets.h

src/util/readwritefile.cpp

src/util/fastrange.h

src/util/signalinterrupt.h

src/util/task_runner.h

src/util/syserror.cpp

src/common/interfaces.cpp

src/common/types.h

src/util/threadinterrupt.h

src/kernel/chainstatemanager_opts.h

src/node/psbt.h

src/policy/ephemeral_policy.h

src/util/trace.h

src/common/url.cpp

src/kernel/mempool_options.h

src/util/serfloat.cpp

src/kernel/notifications_interface.h

src/node/timeoffsets.cpp

src/node/warnings.cpp

src/util/hash_type.h

src/crypto/hex_base.cpp

src/node/eviction.h

src/util/tokenbucket.h

src/crypto/aes.h

src/common/pcp.h

src/util/feefrac.cpp

src/node/transaction.h

src/util/threadnames.cpp

src/common/signmessage.h

src/util/exec.cpp

src/util/signalinterrupt.cpp

src/clientversion.cpp

src/common/signmessage.cpp

src/compat/assumptions.h

src/compat/byteswap.h

src/deploymentinfo.cpp

src/deploymentinfo.h

src/deploymentstatus.cpp

src/deploymentstatus.h

src/dummywallet.cpp

src/external_signer.h

src/init/bitcoin-gui.cpp

src/init/bitcoin-node.cpp

src/init/bitcoin-qt.cpp

src/init/bitcoin-wallet.cpp

src/init/bitcoind.cpp

src/init/common.h

src/interfaces/init.h

src/interfaces/ipc.h

src/key_io.h

src/logging/categories.h

src/logging/timer.h

src/mapport.h

src/musig.h

src/net_permissions.h

src/netgroup.h

src/netmessagemaker.h

src/node/chainstatemanager_args.cpp

src/node/connection_types.h

src/node/context.h

src/node/interface_ui.h

src/node/mempool_args.cpp

src/node/mining_args.cpp

src/node/minisketchwrapper.cpp

src/node/txreconciliation.h

src/policy/fees/estimator_args.cpp

src/policy/fees/estimator_args.h

src/policy/fees/estimator_man.cpp

src/policy/fees/estimator_man.h

src/policy/packages.h

src/policy/rbf.h

src/policy/truc_policy.h

src/pow.h

src/primitives/block.cpp

src/randomenv.h

src/rest.h

src/script/keyorigin.h

src/script/parsing.cpp

src/script/parsing.h

src/script/script_error.h

src/script/sigcache.cpp

src/script/sigcache.h

src/script/solver.h

src/script/verify_flags.h

src/semaphore_grant.h

src/signet.h

src/span.h

src/support/allocators/secure.h

src/support/allocators/zeroafterfree.h

src/util/tokenpipe.cpp

src/util/translation.h

src/util/vector.h

src/versionbits.h

src/versionbits_impl.h

src/wallet/external_signer_scriptpubkeyman.h

src/wallet/fees.h

src/wallet/load.h

src/wallet/receive.h

src/wallet/rpc/wallet.h

src/wallet/types.h

src/walletinitinterface.h

src/zmq/zmqabstractnotifier.cpp

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