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this shit doesn't work.

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fiatjaf
2024-12-24 19:30:29 -03:00
parent 95ddacb9f3
commit 654857d5ab
157 changed files with 71872 additions and 4 deletions
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30
libsecp256k1/examples/CMakeLists.txt Normal file
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function(add_example name)
set(target_name ${name}_example)
add_executable(${target_name} ${name}.c)
target_include_directories(${target_name} PRIVATE
${PROJECT_SOURCE_DIR}/include
)
target_link_libraries(${target_name}
secp256k1
$<$<PLATFORM_ID:Windows>:bcrypt>
)
set(test_name ${name}_example)
add_test(NAME ${test_name} COMMAND ${target_name})
if(BUILD_SHARED_LIBS AND MSVC)
# The DLL must reside either in the same folder where the executable is
# or somewhere in PATH. Using the latter option.
set_tests_properties(${test_name} PROPERTIES
ENVIRONMENT "PATH=$<TARGET_FILE_DIR:secp256k1>;$ENV{PATH}"
)
endif()
endfunction()
add_example(ecdsa)
if(SECP256K1_ENABLE_MODULE_ECDH)
add_example(ecdh)
endif()
if(SECP256K1_ENABLE_MODULE_SCHNORRSIG)
add_example(schnorr)
endif()

121
libsecp256k1/examples/EXAMPLES_COPYING Normal file
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122
libsecp256k1/examples/ecdh.c Normal file
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/*************************************************************************
* Written in 2020-2022 by Elichai Turkel *
* To the extent possible under law, the author(s) have dedicated all *
* copyright and related and neighboring rights to the software in this *
* file to the public domain worldwide. This software is distributed *
* without any warranty. For the CC0 Public Domain Dedication, see *
* EXAMPLES_COPYING or https://creativecommons.org/publicdomain/zero/1.0 *
*************************************************************************/
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <secp256k1.h>
#include <secp256k1_ecdh.h>
#include "examples_util.h"
int main(void) {
unsigned char seckey1[32];
unsigned char seckey2[32];
unsigned char compressed_pubkey1[33];
unsigned char compressed_pubkey2[33];
unsigned char shared_secret1[32];
unsigned char shared_secret2[32];
unsigned char randomize[32];
int return_val;
size_t len;
secp256k1_pubkey pubkey1;
secp256k1_pubkey pubkey2;
/* Before we can call actual API functions, we need to create a "context". */
secp256k1_context* ctx = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
if (!fill_random(randomize, sizeof(randomize))) {
printf("Failed to generate randomness\n");
return 1;
}
/* Randomizing the context is recommended to protect against side-channel
* leakage See `secp256k1_context_randomize` in secp256k1.h for more
* information about it. This should never fail. */
return_val = secp256k1_context_randomize(ctx, randomize);
assert(return_val);
/*** Key Generation ***/
/* If the secret key is zero or out of range (bigger than secp256k1's
* order), we try to sample a new key. Note that the probability of this
* happening is negligible. */
while (1) {
if (!fill_random(seckey1, sizeof(seckey1)) || !fill_random(seckey2, sizeof(seckey2))) {
printf("Failed to generate randomness\n");
return 1;
}
if (secp256k1_ec_seckey_verify(ctx, seckey1) && secp256k1_ec_seckey_verify(ctx, seckey2)) {
break;
}
}
/* Public key creation using a valid context with a verified secret key should never fail */
return_val = secp256k1_ec_pubkey_create(ctx, &pubkey1, seckey1);
assert(return_val);
return_val = secp256k1_ec_pubkey_create(ctx, &pubkey2, seckey2);
assert(return_val);
/* Serialize pubkey1 in a compressed form (33 bytes), should always return 1 */
len = sizeof(compressed_pubkey1);
return_val = secp256k1_ec_pubkey_serialize(ctx, compressed_pubkey1, &len, &pubkey1, SECP256K1_EC_COMPRESSED);
assert(return_val);
/* Should be the same size as the size of the output, because we passed a 33 byte array. */
assert(len == sizeof(compressed_pubkey1));
/* Serialize pubkey2 in a compressed form (33 bytes) */
len = sizeof(compressed_pubkey2);
return_val = secp256k1_ec_pubkey_serialize(ctx, compressed_pubkey2, &len, &pubkey2, SECP256K1_EC_COMPRESSED);
assert(return_val);
/* Should be the same size as the size of the output, because we passed a 33 byte array. */
assert(len == sizeof(compressed_pubkey2));
/*** Creating the shared secret ***/
/* Perform ECDH with seckey1 and pubkey2. Should never fail with a verified
* seckey and valid pubkey */
return_val = secp256k1_ecdh(ctx, shared_secret1, &pubkey2, seckey1, NULL, NULL);
assert(return_val);
/* Perform ECDH with seckey2 and pubkey1. Should never fail with a verified
* seckey and valid pubkey */
return_val = secp256k1_ecdh(ctx, shared_secret2, &pubkey1, seckey2, NULL, NULL);
assert(return_val);
/* Both parties should end up with the same shared secret */
return_val = memcmp(shared_secret1, shared_secret2, sizeof(shared_secret1));
assert(return_val == 0);
printf("Secret Key1: ");
print_hex(seckey1, sizeof(seckey1));
printf("Compressed Pubkey1: ");
print_hex(compressed_pubkey1, sizeof(compressed_pubkey1));
printf("\nSecret Key2: ");
print_hex(seckey2, sizeof(seckey2));
printf("Compressed Pubkey2: ");
print_hex(compressed_pubkey2, sizeof(compressed_pubkey2));
printf("\nShared Secret: ");
print_hex(shared_secret1, sizeof(shared_secret1));
/* This will clear everything from the context and free the memory */
secp256k1_context_destroy(ctx);
/* It's best practice to try to clear secrets from memory after using them.
* This is done because some bugs can allow an attacker to leak memory, for
* example through "out of bounds" array access (see Heartbleed), Or the OS
* swapping them to disk. Hence, we overwrite the secret key buffer with zeros.
*
* Here we are preventing these writes from being optimized out, as any good compiler
* will remove any writes that aren't used. */
secure_erase(seckey1, sizeof(seckey1));
secure_erase(seckey2, sizeof(seckey2));
secure_erase(shared_secret1, sizeof(shared_secret1));
secure_erase(shared_secret2, sizeof(shared_secret2));
return 0;
}

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libsecp256k1/examples/ecdsa.c Normal file
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/*************************************************************************
* Written in 2020-2022 by Elichai Turkel *
* To the extent possible under law, the author(s) have dedicated all *
* copyright and related and neighboring rights to the software in this *
* file to the public domain worldwide. This software is distributed *
* without any warranty. For the CC0 Public Domain Dedication, see *
* EXAMPLES_COPYING or https://creativecommons.org/publicdomain/zero/1.0 *
*************************************************************************/
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <secp256k1.h>
#include "examples_util.h"
int main(void) {
/* Instead of signing the message directly, we must sign a 32-byte hash.
* Here the message is "Hello, world!" and the hash function was SHA-256.
* An actual implementation should just call SHA-256, but this example
* hardcodes the output to avoid depending on an additional library.
* See https://bitcoin.stackexchange.com/questions/81115/if-someone-wanted-to-pretend-to-be-satoshi-by-posting-a-fake-signature-to-defrau/81116#81116 */
unsigned char msg_hash[32] = {
0x31, 0x5F, 0x5B, 0xDB, 0x76, 0xD0, 0x78, 0xC4,
0x3B, 0x8A, 0xC0, 0x06, 0x4E, 0x4A, 0x01, 0x64,
0x61, 0x2B, 0x1F, 0xCE, 0x77, 0xC8, 0x69, 0x34,
0x5B, 0xFC, 0x94, 0xC7, 0x58, 0x94, 0xED, 0xD3,
};
unsigned char seckey[32];
unsigned char randomize[32];
unsigned char compressed_pubkey[33];
unsigned char serialized_signature[64];
size_t len;
int is_signature_valid, is_signature_valid2;
int return_val;
secp256k1_pubkey pubkey;
secp256k1_ecdsa_signature sig;
/* Before we can call actual API functions, we need to create a "context". */
secp256k1_context* ctx = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
if (!fill_random(randomize, sizeof(randomize))) {
printf("Failed to generate randomness\n");
return 1;
}
/* Randomizing the context is recommended to protect against side-channel
* leakage See `secp256k1_context_randomize` in secp256k1.h for more
* information about it. This should never fail. */
return_val = secp256k1_context_randomize(ctx, randomize);
assert(return_val);
/*** Key Generation ***/
/* If the secret key is zero or out of range (bigger than secp256k1's
* order), we try to sample a new key. Note that the probability of this
* happening is negligible. */
while (1) {
if (!fill_random(seckey, sizeof(seckey))) {
printf("Failed to generate randomness\n");
return 1;
}
if (secp256k1_ec_seckey_verify(ctx, seckey)) {
break;
}
}
/* Public key creation using a valid context with a verified secret key should never fail */
return_val = secp256k1_ec_pubkey_create(ctx, &pubkey, seckey);
assert(return_val);
/* Serialize the pubkey in a compressed form(33 bytes). Should always return 1. */
len = sizeof(compressed_pubkey);
return_val = secp256k1_ec_pubkey_serialize(ctx, compressed_pubkey, &len, &pubkey, SECP256K1_EC_COMPRESSED);
assert(return_val);
/* Should be the same size as the size of the output, because we passed a 33 byte array. */
assert(len == sizeof(compressed_pubkey));
/*** Signing ***/
/* Generate an ECDSA signature `noncefp` and `ndata` allows you to pass a
* custom nonce function, passing `NULL` will use the RFC-6979 safe default.
* Signing with a valid context, verified secret key
* and the default nonce function should never fail. */
return_val = secp256k1_ecdsa_sign(ctx, &sig, msg_hash, seckey, NULL, NULL);
assert(return_val);
/* Serialize the signature in a compact form. Should always return 1
* according to the documentation in secp256k1.h. */
return_val = secp256k1_ecdsa_signature_serialize_compact(ctx, serialized_signature, &sig);
assert(return_val);
/*** Verification ***/
/* Deserialize the signature. This will return 0 if the signature can't be parsed correctly. */
if (!secp256k1_ecdsa_signature_parse_compact(ctx, &sig, serialized_signature)) {
printf("Failed parsing the signature\n");
return 1;
}
/* Deserialize the public key. This will return 0 if the public key can't be parsed correctly. */
if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, compressed_pubkey, sizeof(compressed_pubkey))) {
printf("Failed parsing the public key\n");
return 1;
}
/* Verify a signature. This will return 1 if it's valid and 0 if it's not. */
is_signature_valid = secp256k1_ecdsa_verify(ctx, &sig, msg_hash, &pubkey);
printf("Is the signature valid? %s\n", is_signature_valid ? "true" : "false");
printf("Secret Key: ");
print_hex(seckey, sizeof(seckey));
printf("Public Key: ");
print_hex(compressed_pubkey, sizeof(compressed_pubkey));
printf("Signature: ");
print_hex(serialized_signature, sizeof(serialized_signature));
/* This will clear everything from the context and free the memory */
secp256k1_context_destroy(ctx);
/* Bonus example: if all we need is signature verification (and no key
generation or signing), we don't need to use a context created via
secp256k1_context_create(). We can simply use the static (i.e., global)
context secp256k1_context_static. See its description in
include/secp256k1.h for details. */
is_signature_valid2 = secp256k1_ecdsa_verify(secp256k1_context_static,
&sig, msg_hash, &pubkey);
assert(is_signature_valid2 == is_signature_valid);
/* It's best practice to try to clear secrets from memory after using them.
* This is done because some bugs can allow an attacker to leak memory, for
* example through "out of bounds" array access (see Heartbleed), Or the OS
* swapping them to disk. Hence, we overwrite the secret key buffer with zeros.
*
* Here we are preventing these writes from being optimized out, as any good compiler
* will remove any writes that aren't used. */
secure_erase(seckey, sizeof(seckey));
return 0;
}

108
libsecp256k1/examples/examples_util.h Normal file
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/*************************************************************************
* Copyright (c) 2020-2021 Elichai Turkel *
* Distributed under the CC0 software license, see the accompanying file *
* EXAMPLES_COPYING or https://creativecommons.org/publicdomain/zero/1.0 *
*************************************************************************/
/*
* This file is an attempt at collecting best practice methods for obtaining randomness with different operating systems.
* It may be out-of-date. Consult the documentation of the operating system before considering to use the methods below.
*
* Platform randomness sources:
* Linux -> `getrandom(2)`(`sys/random.h`), if not available `/dev/urandom` should be used. http://man7.org/linux/man-pages/man2/getrandom.2.html, https://linux.die.net/man/4/urandom
* macOS -> `getentropy(2)`(`sys/random.h`), if not available `/dev/urandom` should be used. https://www.unix.com/man-page/mojave/2/getentropy, https://opensource.apple.com/source/xnu/xnu-517.12.7/bsd/man/man4/random.4.auto.html
* FreeBSD -> `getrandom(2)`(`sys/random.h`), if not available `kern.arandom` should be used. https://www.freebsd.org/cgi/man.cgi?query=getrandom, https://www.freebsd.org/cgi/man.cgi?query=random&sektion=4
* OpenBSD -> `getentropy(2)`(`unistd.h`), if not available `/dev/urandom` should be used. https://man.openbsd.org/getentropy, https://man.openbsd.org/urandom
* Windows -> `BCryptGenRandom`(`bcrypt.h`). https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom
*/
#if defined(_WIN32)
/*
* The defined WIN32_NO_STATUS macro disables return code definitions in
* windows.h, which avoids "macro redefinition" MSVC warnings in ntstatus.h.
*/
#define WIN32_NO_STATUS
#include <windows.h>
#undef WIN32_NO_STATUS
#include <ntstatus.h>
#include <bcrypt.h>
#elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
#include <sys/random.h>
#elif defined(__OpenBSD__)
#include <unistd.h>
#else
#error "Couldn't identify the OS"
#endif
#include <stddef.h>
#include <limits.h>
#include <stdio.h>
/* Returns 1 on success, and 0 on failure. */
static int fill_random(unsigned char* data, size_t size) {
#if defined(_WIN32)
NTSTATUS res = BCryptGenRandom(NULL, data, size, BCRYPT_USE_SYSTEM_PREFERRED_RNG);
if (res != STATUS_SUCCESS || size > ULONG_MAX) {
return 0;
} else {
return 1;
}
#elif defined(__linux__) || defined(__FreeBSD__)
/* If `getrandom(2)` is not available you should fallback to /dev/urandom */
ssize_t res = getrandom(data, size, 0);
if (res < 0 || (size_t)res != size ) {
return 0;
} else {
return 1;
}
#elif defined(__APPLE__) || defined(__OpenBSD__)
/* If `getentropy(2)` is not available you should fallback to either
* `SecRandomCopyBytes` or /dev/urandom */
int res = getentropy(data, size);
if (res == 0) {
return 1;
} else {
return 0;
}
#endif
return 0;
}
static void print_hex(unsigned char* data, size_t size) {
size_t i;
printf("0x");
for (i = 0; i < size; i++) {
printf("%02x", data[i]);
}
printf("\n");
}
#if defined(_MSC_VER)
// For SecureZeroMemory
#include <Windows.h>
#endif
/* Cleanses memory to prevent leaking sensitive info. Won't be optimized out. */
static void secure_erase(void *ptr, size_t len) {
#if defined(_MSC_VER)
/* SecureZeroMemory is guaranteed not to be optimized out by MSVC. */
SecureZeroMemory(ptr, len);
#elif defined(__GNUC__)
/* We use a memory barrier that scares the compiler away from optimizing out the memset.
*
* Quoting Adam Langley <agl@google.com> in commit ad1907fe73334d6c696c8539646c21b11178f20f
* in BoringSSL (ISC License):
* As best as we can tell, this is sufficient to break any optimisations that
* might try to eliminate "superfluous" memsets.
* This method used in memzero_explicit() the Linux kernel, too. Its advantage is that it is
* pretty efficient, because the compiler can still implement the memset() efficiently,
* just not remove it entirely. See "Dead Store Elimination (Still) Considered Harmful" by
* Yang et al. (USENIX Security 2017) for more background.
*/
memset(ptr, 0, len);
__asm__ __volatile__("" : : "r"(ptr) : "memory");
#else
void *(*volatile const volatile_memset)(void *, int, size_t) = memset;
volatile_memset(ptr, 0, len);
#endif
}

156
libsecp256k1/examples/schnorr.c Normal file
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/*************************************************************************
* Written in 2020-2022 by Elichai Turkel *
* To the extent possible under law, the author(s) have dedicated all *
* copyright and related and neighboring rights to the software in this *
* file to the public domain worldwide. This software is distributed *
* without any warranty. For the CC0 Public Domain Dedication, see *
* EXAMPLES_COPYING or https://creativecommons.org/publicdomain/zero/1.0 *
*************************************************************************/
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <secp256k1.h>
#include <secp256k1_extrakeys.h>
#include <secp256k1_schnorrsig.h>
#include "examples_util.h"
int main(void) {
unsigned char msg[12] = "Hello World!";
unsigned char msg_hash[32];
unsigned char tag[17] = "my_fancy_protocol";
unsigned char seckey[32];
unsigned char randomize[32];
unsigned char auxiliary_rand[32];
unsigned char serialized_pubkey[32];
unsigned char signature[64];
int is_signature_valid, is_signature_valid2;
int return_val;
secp256k1_xonly_pubkey pubkey;
secp256k1_keypair keypair;
/* Before we can call actual API functions, we need to create a "context". */
secp256k1_context* ctx = secp256k1_context_create(SECP256K1_CONTEXT_NONE);
if (!fill_random(randomize, sizeof(randomize))) {
printf("Failed to generate randomness\n");
return 1;
}
/* Randomizing the context is recommended to protect against side-channel
* leakage See `secp256k1_context_randomize` in secp256k1.h for more
* information about it. This should never fail. */
return_val = secp256k1_context_randomize(ctx, randomize);
assert(return_val);
/*** Key Generation ***/
/* If the secret key is zero or out of range (bigger than secp256k1's
* order), we try to sample a new key. Note that the probability of this
* happening is negligible. */
while (1) {
if (!fill_random(seckey, sizeof(seckey))) {
printf("Failed to generate randomness\n");
return 1;
}
/* Try to create a keypair with a valid context, it should only fail if
* the secret key is zero or out of range. */
if (secp256k1_keypair_create(ctx, &keypair, seckey)) {
break;
}
}
/* Extract the X-only public key from the keypair. We pass NULL for
* `pk_parity` as the parity isn't needed for signing or verification.
* `secp256k1_keypair_xonly_pub` supports returning the parity for
* other use cases such as tests or verifying Taproot tweaks.
* This should never fail with a valid context and public key. */
return_val = secp256k1_keypair_xonly_pub(ctx, &pubkey, NULL, &keypair);
assert(return_val);
/* Serialize the public key. Should always return 1 for a valid public key. */
return_val = secp256k1_xonly_pubkey_serialize(ctx, serialized_pubkey, &pubkey);
assert(return_val);
/*** Signing ***/
/* Instead of signing (possibly very long) messages directly, we sign a
* 32-byte hash of the message in this example.
*
* We use secp256k1_tagged_sha256 to create this hash. This function expects
* a context-specific "tag", which restricts the context in which the signed
* messages should be considered valid. For example, if protocol A mandates
* to use the tag "my_fancy_protocol" and protocol B mandates to use the tag
* "my_boring_protocol", then signed messages from protocol A will never be
* valid in protocol B (and vice versa), even if keys are reused across
* protocols. This implements "domain separation", which is considered good
* practice. It avoids attacks in which users are tricked into signing a
* message that has intended consequences in the intended context (e.g.,
* protocol A) but would have unintended consequences if it were valid in
* some other context (e.g., protocol B). */
return_val = secp256k1_tagged_sha256(ctx, msg_hash, tag, sizeof(tag), msg, sizeof(msg));
assert(return_val);
/* Generate 32 bytes of randomness to use with BIP-340 schnorr signing. */
if (!fill_random(auxiliary_rand, sizeof(auxiliary_rand))) {
printf("Failed to generate randomness\n");
return 1;
}
/* Generate a Schnorr signature.
*
* We use the secp256k1_schnorrsig_sign32 function that provides a simple
* interface for signing 32-byte messages (which in our case is a hash of
* the actual message). BIP-340 recommends passing 32 bytes of randomness
* to the signing function to improve security against side-channel attacks.
* Signing with a valid context, a 32-byte message, a verified keypair, and
* any 32 bytes of auxiliary random data should never fail. */
return_val = secp256k1_schnorrsig_sign32(ctx, signature, msg_hash, &keypair, auxiliary_rand);
assert(return_val);
/*** Verification ***/
/* Deserialize the public key. This will return 0 if the public key can't
* be parsed correctly */
if (!secp256k1_xonly_pubkey_parse(ctx, &pubkey, serialized_pubkey)) {
printf("Failed parsing the public key\n");
return 1;
}
/* Compute the tagged hash on the received messages using the same tag as the signer. */
return_val = secp256k1_tagged_sha256(ctx, msg_hash, tag, sizeof(tag), msg, sizeof(msg));
assert(return_val);
/* Verify a signature. This will return 1 if it's valid and 0 if it's not. */
is_signature_valid = secp256k1_schnorrsig_verify(ctx, signature, msg_hash, 32, &pubkey);
printf("Is the signature valid? %s\n", is_signature_valid ? "true" : "false");
printf("Secret Key: ");
print_hex(seckey, sizeof(seckey));
printf("Public Key: ");
print_hex(serialized_pubkey, sizeof(serialized_pubkey));
printf("Signature: ");
print_hex(signature, sizeof(signature));
/* This will clear everything from the context and free the memory */
secp256k1_context_destroy(ctx);
/* Bonus example: if all we need is signature verification (and no key
generation or signing), we don't need to use a context created via
secp256k1_context_create(). We can simply use the static (i.e., global)
context secp256k1_context_static. See its description in
include/secp256k1.h for details. */
is_signature_valid2 = secp256k1_schnorrsig_verify(secp256k1_context_static,
signature, msg_hash, 32, &pubkey);
assert(is_signature_valid2 == is_signature_valid);
/* It's best practice to try to clear secrets from memory after using them.
* This is done because some bugs can allow an attacker to leak memory, for
* example through "out of bounds" array access (see Heartbleed), Or the OS
* swapping them to disk. Hence, we overwrite the secret key buffer with zeros.
*
* Here we are preventing these writes from being optimized out, as any good compiler
* will remove any writes that aren't used. */
secure_erase(seckey, sizeof(seckey));
return 0;
}