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author | fanquake <fanquake@gmail.com> | 2022-04-06 20:20:30 +0100 |
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committer | fanquake <fanquake@gmail.com> | 2022-04-06 20:20:30 +0100 |
commit | 2619657c993a228ca4c5c1a1085d5a6bcf5946cb (patch) | |
tree | f1b7d33e0271d46eca94f73c4d33cd1cd77f0f4c /src/secp256k1/examples/random.h | |
parent | 41720a1f540ef3c16a283a6cce6f0a63552a4937 (diff) | |
parent | afb7a6fe06a33956ef43429d31f5934448f6e671 (diff) | |
download | bitcoin-2619657c993a228ca4c5c1a1085d5a6bcf5946cb.tar.xz |
Update secp256k1 subtree to latest upstream master
Diffstat (limited to 'src/secp256k1/examples/random.h')
-rw-r--r-- | src/secp256k1/examples/random.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/secp256k1/examples/random.h b/src/secp256k1/examples/random.h new file mode 100644 index 0000000000..439226f09f --- /dev/null +++ b/src/secp256k1/examples/random.h @@ -0,0 +1,73 @@ +/************************************************************************* + * 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 + * It may be out-of-date.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) +#include <windows.h> +#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"); +} |