[PATCH 2/3] v4.0 Blowfish: Add bcrypt support.

--- Makefile.in | 2 +- blowfish-bcrypt.c | 519 ++++++++++++++++++++++++++++++++++++++++++++++ blowfish.h | 15 ++ nettle.texinfo | 67 ++++++ 4 files changed, 602 insertions(+), 1 deletion(-) create mode 100644 blowfish-bcrypt.c

diff --git a/Makefile.in b/Makefile.in index 64ff1001..77efb5c9 100644 --- a/Makefile.in +++ b/Makefile.in @@ -73,7 +73,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \ aes256-set-encrypt-key.c aes256-set-decrypt-key.c \ aes256-meta.c \ arcfour.c arcfour-crypt.c \ - arctwo.c arctwo-meta.c blowfish.c \ + arctwo.c arctwo-meta.c blowfish.c blowfish-bcrypt.c \ base16-encode.c base16-decode.c base16-meta.c \ base64-encode.c base64-decode.c base64-meta.c \ base64url-encode.c base64url-decode.c base64url-meta.c \ diff --git a/blowfish-bcrypt.c b/blowfish-bcrypt.c new file mode 100644 index 00000000..c06f9e90 --- /dev/null +++ b/blowfish-bcrypt.c @@ -0,0 +1,519 @@ +/* blowfish-bcrypt.c + + The blowfish bcrypt implementation. + + Copyright (c) 2020 Stephen R. van den Berg + + This file is part of GNU Nettle. + + GNU Nettle is free software: you can redistribute it and/or + modify it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at your + option) any later version. + + or both in parallel, as here. + + GNU Nettle is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see http://www.gnu.org/licenses/. +*/ + +#if HAVE_CONFIG_H +#include "config.h" +#endif + +#include <assert.h> +#include <string.h> +#include <stdlib.h> + +#include "blowfish.h" +#include "blowfish-internal.h" +#include "base64.h" + +#include "macros.h" + +#define CRYPTPLEN 7 +#define SALTLEN ((BLOWFISH_BCRYPT_BINSALT_SIZE*8+5) / 6) + +#define HASHOFFSET (CRYPTPLEN + SALTLEN) + +static const signed char radix64_decode_table[0x100] = { + /* White space is HT, VT, FF, CR, LF and SPC */ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, + 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, -1, -1, -1, -3, -1, -1, + -1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, + 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, -1, -1, -1, -1, -1, + -1, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, + 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +}; + +static const char radix64_encode_table[64] = + "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789"; + +int +blowfish_bcrypt_verify(const char *key, + const char *hashed) +{ + char newhash[BLOWFISH_BCRYPT_HASH_SIZE]; + + return blowfish_bcrypt_hash(sizeof newhash, + newhash, key, hashed, -1, (void*)0) + && !strcmp(newhash, hashed); +} + +static char *encode_radix64(char *dst, size_t len, const uint8_t *src) +{ + struct base64_encode_ctx ctx; + base64_encode_init(&ctx); + ctx.alphabet = radix64_encode_table; + dst += base64_encode_update(&ctx, dst, len, src); + dst += base64_encode_final(&ctx, dst); + *--dst = '\0'; /* Strip the trailing = */ + return dst; +} + +/* + * Large parts of the code below are based on public domain sources. + * The comments and copyright notices have been preserved. + * Any code added or modified by me is licensed under the + * licenses listed above. -- Stephen R. van den Berg + */ + +/* + * This code comes from John the Ripper password cracker, with reentrant + * and crypt(3) interfaces added, but optimizations specific to password + * cracking removed. + * + * Written by Solar Designer <solar at openwall.com> in 1998-2015. + * No copyright is claimed, and the software is hereby placed in the public + * domain. In case this attempt to disclaim copyright and place the software + * in the public domain is deemed null and void, then the software is + * Copyright (c) 1998-2015 Solar Designer and it is hereby released to the + * general public under the following terms: + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted. + * + * There's ABSOLUTELY NO WARRANTY, express or implied. + * + * It is my intent that you should be able to use this on your system, + * as part of a software package, or anywhere else to improve security, + * ensure compatibility, or for any other purpose. I would appreciate + * it if you give credit where it is due and keep your modifications in + * the public domain as well, but I don't require that in order to let + * you place this code and any modifications you make under a license + * of your choice. + * + * This implementation is fully compatible with OpenBSD's bcrypt.c for prefix + * "$2b$", originally by Niels Provos <provos at citi.umich.edu>, and it uses + * some of his ideas. The password hashing algorithm was designed by David + * Mazieres <dm at lcs.mit.edu>. For information on the level of + * compatibility for bcrypt hash prefixes other than "$2b$", please refer to + * the comments in set_key() below and to the included crypt(3) man page. + */ + +typedef uint32_t bf_key[_BLOWFISH_ROUNDS + 2]; + +/* + * Magic IV for 64 Blowfish encryptions that we do at the end. + * The string is "OrpheanBeholderScryDoubt" on big-endian. + */ +static uint32_t magic_w[6] = { + 0x4F727068, 0x65616E42, 0x65686F6C, + 0x64657253, 0x63727944, 0x6F756274 +}; + +static void swap32(uint32_t *x, int count) +{ +#if !WORDS_BIGENDIAN + do { + uint32_t tmp = *x; + tmp = (tmp << 16) | (tmp >> 16); + *x++ = ((tmp & 0x00FF00FF) << 8) | ((tmp >> 8) & 0x00FF00FF); + } while (--count); +#endif +} + +static void set_xkey(const char *key, bf_key expanded, bf_key initial, + unsigned bug, uint32_t safety) +{ + const char *ptr = key; + unsigned i, j; + uint32_t sign, diff, tmp[2]; + +/* + * There was a sign extension bug in older revisions of this function. While + * we would have liked to simply fix the bug and move on, we have to provide + * a backwards compatibility feature (essentially the bug) for some systems and + * a safety measure for some others. The latter is needed because for certain + * multiple inputs to the buggy algorithm there exist easily found inputs to + * the correct algorithm that produce the same hash. Thus, we optionally + * deviate from the correct algorithm just enough to avoid such collisions. + * While the bug itself affected the majority of passwords containing + * characters with the 8th bit set (although only a percentage of those in a + * collision-producing way), the anti-collision safety measure affects + * only a subset of passwords containing the '\xff' character (not even all of + * those passwords, just some of them). This character is not found in valid + * UTF-8 sequences and is rarely used in popular 8-bit character encodings. + * Thus, the safety measure is unlikely to cause much annoyance, and is a + * reasonable tradeoff to use when authenticating against existing hashes that + * are not reliably known to have been computed with the correct algorithm. + * + * We use an approach that tries to minimize side-channel leaks of password + * information - that is, we mostly use fixed-cost bitwise operations instead + * of branches or table lookups. (One conditional branch based on password + * length remains. It is not part of the bug aftermath, though, and is + * difficult and possibly unreasonable to avoid given the use of C strings by + * the caller, which results in similar timing leaks anyway.) + * + * For actual implementation, we set an array index in the variable "bug" + * (0 means no bug, 1 means sign extension bug emulation) and a flag in the + * variable "safety" (bit 16 is set when the safety measure is requested). + * Valid combinations of settings are: + * + * Prefix "$2a$": bug = 0, safety = 0x10000 + * Prefix "$2b$": bug = 0, safety = 0 + * Prefix "$2x$": bug = 1, safety = 0 + * Prefix "$2y$": bug = 0, safety = 0 + */ + + sign = diff = 0; + + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i++) { + tmp[0] = tmp[1] = 0; + for (j = 0; j < 4; j++) { + tmp[0] <<= 8; + tmp[0] |= (unsigned char)*ptr; /* correct */ + tmp[1] <<= 8; + tmp[1] |= (signed char)*ptr; /* bug */ +/* + * Sign extension in the first char has no effect - nothing to overwrite yet, + * and those extra 24 bits will be fully shifted out of the 32-bit word. For + * chars 2, 3, 4 in each four-char block, we set bit 7 of "sign" if sign + * extension in tmp[1] occurs. Once this flag is set, it remains set. + */ + if (j) + sign |= tmp[1] & 0x80; + if (!*ptr) + ptr = key; + else + ptr++; + } + diff |= tmp[0] ^ tmp[1]; /* Non-zero on any differences */ + + expanded[i] = tmp[bug]; + initial[i] = _nettle_blowfish_initial_ctx.p[i] ^ tmp[bug]; + } + +/* + * At this point, "diff" is zero if the correct and buggy algorithms produced + * exactly the same result. If so and if "sign" is non-zero, which indicates + * that there was a non-benign sign extension, this means that we have a + * collision between the correctly computed hash for this password and a set of + * passwords that could be supplied to the buggy algorithm. Our safety measure + * is meant to protect from such many-buggy to one-correct collisions, by + * deviating from the correct algorithm in such cases. Let's check for this. + */ + diff |= diff >> 16; /* still zero if exact match */ + diff &= 0xffff; /* ditto */ + diff += 0xffff; /* bit 16 set if "diff" was non-zero (on non-match) */ + sign <<= 9; /* move the non-benign sign extension flag to bit 16 */ + sign &= ~diff & safety; /* action needed? */ + +/* + * If we have determined that we need to deviate from the correct algorithm, + * flip bit 16 in initial expanded key. (The choice of 16 is arbitrary, but + * let's stick to it now. It came out of the approach we used above, and it's + * not any worse than any other choice we could make.) + * + * It is crucial that we don't do the same to the expanded key used in the main + * Eksblowfish loop. By doing it to only one of these two, we deviate from a + * state that could be directly specified by a password to the buggy algorithm + * (and to the fully correct one as well, but that's a side-effect). + */ + initial[0] ^= sign; +} + +static int ibcrypt(size_t length, char *dst, + const char *key, const char *scheme, + int minlog2rounds, + int log2rounds, const uint8_t *salt) +{ + struct { + struct blowfish_ctx ctx; + bf_key expanded_key; + union { + uint32_t salt[4]; + uint32_t output[6]; + } binary; + } data; + uint8_t psalt[BLOWFISH_BCRYPT_BINSALT_SIZE]; + uint32_t L, R; + uint32_t *ptr; + uint32_t count; + int i; + size_t lenscheme = strlen(scheme); + unsigned cscheme; + unsigned bug = 0; + uint32_t safety = 0; + if (length < BLOWFISH_BCRYPT_HASH_SIZE || + lenscheme < 2) + return 0; + + if (lenscheme >= 3 && *scheme++ != '$') + return 0; + if (*scheme++ != '2') + return 0; + + switch (cscheme = *scheme++) { + default: + return 0; + case 'a': safety = 0x10000; + break; + case 'x': bug = 1; + break; + case 'b': case 'y': + break; + } + + if (lenscheme >= 4) { + if (*scheme++ != '$') + return 0; + if (lenscheme >= 6) { + if (log2rounds < 0) + log2rounds = atoi(scheme); + scheme += 2; + if (lenscheme >= CRYPTPLEN && *scheme++ != '$') + return 0; + if (lenscheme >= HASHOFFSET && !salt) { + struct base64_decode_ctx ctx; + size_t saltlen = BLOWFISH_BCRYPT_BINSALT_SIZE; + + base64_decode_init(&ctx); + ctx.table = radix64_decode_table; + + if (!base64_decode_update(&ctx, &saltlen, (uint8_t *) data.binary.salt, + SALTLEN, scheme) + || saltlen != BLOWFISH_BCRYPT_BINSALT_SIZE) + return 0; + } + } + } + + if (salt) + memcpy(data.binary.salt, salt, BLOWFISH_BCRYPT_BINSALT_SIZE); + else if (lenscheme < HASHOFFSET) + return 0; + memcpy(psalt, data.binary.salt, BLOWFISH_BCRYPT_BINSALT_SIZE); + swap32(data.binary.salt, 4); + + if (log2rounds < minlog2rounds || log2rounds > 31) + return 0; + count = (uint32_t)1 << log2rounds; + + set_xkey(key, data.expanded_key, data.ctx.p, bug, safety); + memcpy(data.ctx.s, _nettle_blowfish_initial_ctx.s, sizeof(data.ctx.s)); + + L = R = 0; + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { + L ^= data.binary.salt[i & 2]; + R ^= data.binary.salt[(i & 2) + 1]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + data.ctx.p[i] = L; + data.ctx.p[i + 1] = R; + } + + ptr = data.ctx.s[0]; + do { + ptr += 4; + L ^= data.binary.salt[(_BLOWFISH_ROUNDS + 2) & 3]; + R ^= data.binary.salt[(_BLOWFISH_ROUNDS + 3) & 3]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 4) = L; + *(ptr - 3) = R; + + L ^= data.binary.salt[(_BLOWFISH_ROUNDS + 4) & 3]; + R ^= data.binary.salt[(_BLOWFISH_ROUNDS + 5) & 3]; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.s[3][0xFF]); + + do { + int done; + + for (i = 0; i < _BLOWFISH_ROUNDS + 2; i += 2) { + data.ctx.p[i] ^= data.expanded_key[i]; + data.ctx.p[i + 1] ^= data.expanded_key[i + 1]; + } + + done = 0; + do { + uint32_t tmp1, tmp2, tmp3, tmp4; + + L = R = 0; + ptr = data.ctx.p; + do { + ptr += 2; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.p[_BLOWFISH_ROUNDS + 2]); + + ptr = data.ctx.s[0]; + do { + ptr += 2; + _nettle_blowfish_encround(&data.ctx, &L, &R); + *(ptr - 2) = L; + *(ptr - 1) = R; + } while (ptr < &data.ctx.s[3][0xFF]); + + if (done) + break; + done = 1; + + tmp1 = data.binary.salt[0]; + tmp2 = data.binary.salt[1]; + tmp3 = data.binary.salt[2]; + tmp4 = data.binary.salt[3]; + for (i = 0; i < _BLOWFISH_ROUNDS; i += 4) { + data.ctx.p[i] ^= tmp1; + data.ctx.p[i + 1] ^= tmp2; + data.ctx.p[i + 2] ^= tmp3; + data.ctx.p[i + 3] ^= tmp4; + } + data.ctx.p[16] ^= tmp1; + data.ctx.p[17] ^= tmp2; + } while (1); + } while (--count); + + for (i = 0; i < 6; i += 2) { + L = magic_w[i]; + R = magic_w[i + 1]; + + count = 64; + do + _nettle_blowfish_encround(&data.ctx, &L, &R); + while (--count); + + data.binary.output[i] = L; + data.binary.output[i + 1] = R; + } + + *dst++ = '$'; + *dst++ = '2'; + *dst++ = cscheme; + *dst++ = '$'; + *dst++ = '0' + log2rounds / 10; + *dst++ = '0' + log2rounds % 10; + *dst++ = '$'; + dst = encode_radix64(dst, BLOWFISH_BCRYPT_BINSALT_SIZE, psalt) - 1; + + swap32(data.binary.output, 6); +/* This has to be bug-compatible with the original implementation, so + only encode 23 of the 24 bytes. */ + encode_radix64(dst, 23, (uint8_t *) data.binary.output); + return cscheme; +} + +/* + * Please preserve the runtime self-test. It serves two purposes at once: + * + * 1. We really can't afford the risk of producing incompatible hashes e.g. + * when there's something like gcc bug 26587 again, whereas an application or + * library integrating this code might not also integrate our external tests or + * it might not run them after every build. Even if it does, the miscompile + * might only occur on the production build, but not on a testing build (such + * as because of different optimization settings). It is painful to recover + * from incorrectly-computed hashes - merely fixing whatever broke is not + * enough. Thus, a proactive measure like this self-test is needed. + * + * 2. We don't want to leave sensitive data from our actual password hash + * computation on the stack or in registers. Previous revisions of the code + * would do explicit cleanups, but simply running the self-test after hash + * computation is more reliable. + * + * The performance cost of this quick self-test is around 0.6% at the "$2a$08" + * setting. + */ +int blowfish_bcrypt_hash(size_t length, char *dst, + const char *key, const char *scheme, + int log2rounds, const uint8_t *salt) +{ + const char *test_pw = "8b \xd0\xc1\xd2\xcf\xcc\xd8"; + const char *test_scheme = "$2a$00$abcdefghijklmnopqrstuu"; + static const char * const test_hashes[2] = + {"i1D709vfamulimlGcq0qq3UvuUasvEa\0\x55", /* 'a', 'b', 'y' */ + "VUrPmXD6q/nVSSp7pNDhCR9071IfIRe\0\x55"}; /* 'x' */ + const char *test_hash = test_hashes[0]; + int cscheme; + int ok; + struct { + char s[HASHOFFSET + 1]; + char o[HASHOFFSET + 31 + 1 + 1 + 1]; + } buf; + + if (length) + *dst = '\0'; +/* Hash the supplied password */ + cscheme = ibcrypt(length, dst, key, scheme, 4, log2rounds, salt); + +/* + * Do a quick self-test. It is important that we make both calls to ibcrypt() + * from the same scope such that they likely use the same stack locations, + * which makes the second call overwrite the first call's sensitive data on the + * stack and makes it more likely that any alignment related issues would be + * detected by the self-test. + */ + memcpy(buf.s, test_scheme, sizeof(buf.s)); + + if (cscheme) + test_hash = test_hashes[(buf.s[2] = cscheme) == 'x']; + + memset(buf.o, 0x55, sizeof(buf.o)); + buf.o[sizeof(buf.o) - 1] = 0; + ok = ibcrypt(sizeof(buf.o) - (1 + 1), buf.o, test_pw, + buf.s, 0, -1, (void*)0); + + ok = (ok && + !memcmp(buf.o, buf.s, HASHOFFSET) && + !memcmp(buf.o + HASHOFFSET, test_hash, 31 + 1 + 1 + 1)); + + { + const char *k = "\xff\xa3" "34" "\xff\xff\xff\xa3" "345"; + bf_key ae, ai, ye, yi; + set_xkey(k, ae, ai, 0, 0x10000); /* $2a$ */ + set_xkey(k, ye, yi, 0, 0); /* $2y$ */ + ai[0] ^= 0x10000; /* undo the safety (for comparison) */ + ok = ok && ai[0] == 0xdb9c59bc && ye[17] == 0x33343500 && + !memcmp(ae, ye, sizeof(ae)) && + !memcmp(ai, yi, sizeof(ai)); + } + + return ok && !!cscheme; +} diff --git a/blowfish.h b/blowfish.h index bcdc7cb6..af48e20f 100644 --- a/blowfish.h +++ b/blowfish.h @@ -46,6 +46,8 @@ extern "C" { #define blowfish128_set_key nettle_blowfish128_set_key #define blowfish_encrypt nettle_blowfish_encrypt #define blowfish_decrypt nettle_blowfish_decrypt +#define blowfish_bcrypt_hash nettle_blowfish_bcrypt_hash +#define blowfish_bcrypt_verify nettle_blowfish_bcrypt_verify

#define BLOWFISH_BLOCK_SIZE 8

@@ -60,6 +62,9 @@ extern "C" {

#define _BLOWFISH_ROUNDS 16

+#define BLOWFISH_BCRYPT_HASH_SIZE (60 + 1) /* Including null-terminator */ +#define BLOWFISH_BCRYPT_BINSALT_SIZE 16 /* Binary string size */ + struct blowfish_ctx { uint32_t s[4][256]; @@ -81,6 +86,16 @@ void blowfish_decrypt(const struct blowfish_ctx *ctx, size_t length, uint8_t *dst, const uint8_t *src); +int +blowfish_bcrypt_hash(size_t length, + char *dst, + const char *key, + const char *scheme, + int log2rounds, + const uint8_t *salt); +int +blowfish_bcrypt_verify(const char *key, + const char *hashed);

#ifdef __cplusplus } diff --git a/nettle.texinfo b/nettle.texinfo index 995d5de8..75e18b58 100644 --- a/nettle.texinfo +++ b/nettle.texinfo @@ -1513,6 +1513,73 @@ in any other way. Analogous to @code{blowfish_encrypt} @end deftypefun

+@deftypefun int blowfish_bcrypt_hash (size_t @var{length}, char *@var{dst}, const char *@var{key}, const char *@var{scheme}, int @var{log2rounds}, const uint8_t *@var{salt}) +Compute the bcrypt password hash. +The function will return @code{0} if the hash cannot be computed +due to invalid input. +The function will return @code{1} and store the computed hash +in the array pointed to by @var{dst}. The hash is computed based +on the chosen @var{scheme}, number of rounds @var{log2rounds} and +specified @var{salt}. + +@var{length} must be at least @code{BLOWFISH_BCRYPT_HASH_SIZE}. + +@var{dst} must point to a character array of the specified @var{length}. + +@var{key} contains the zero terminated plaintext password string. + +@var{scheme} contains either just the chosen scheme (valid schemes +are: @code{2a}, @code{2b}, @code{2x} or @code{2y}), or +(the prefix of) an existing hashed password (typically @code{$2b$10$...}). + +@var{log2rounds} contains the log2 of the number of encryption rounds +that must be used to compute the hash. If it is @code{-1} the value +will be extracted from @var{scheme}. + +@var{salt} should point to an array of @code{BLOWFISH_BCRYPT_BINSALT_SIZE} +random bytes to be used to perturb the hash computation. If it is @code{NULL} +the salt will be extracted from @var{scheme}. + +Sample code to generate a bcrypt hash: +@example +char cleartxtpassword[] = "ExamplePassword"; +uint8_t salt[BLOWFISH_BCRYPT_BINSALT_SIZE]; +@dots{} +/* Make sure that salt is filled with random bytes */ +@dots{} +char hashedresult[BLOWFISH_BCRYPT_HASH_SIZE]; +int result = blowfish_bcrypt(sizeof(hashedresult), hashedresult, + cleartxtpassword, "2b", 10, salt); +if (result) + printf("%s\n", hashedresult); +@end example +@end deftypefun + +@deftypefun int blowfish_bcrypt_verify (const char *@var{key}, const char *@var{hashed}) +Verifies the bcrypt password hash against the supplied plaintext password. +The function will return @code{0} if the password does not match. +The function will return @code{1} if the password matches. + +@var{key} contains the zero terminated plaintext password string. + +@var{hashed} contains the zero terminated hashed string to compare with. + +Sample code to verify a bcrypt hash: +@example +char cleartxtpassword[] = "ExamplePassword"; +char existinghashed[] = + "$2y$" /* Hash algorithm version */ + "10" /* 2^10 hash rounds (strength) */ + "$" /* separator */ + "1b2lPgo4XumibnJGN3r3sO" /* base64 encoded 16-byte salt */ + "u7wE7xNfYDKlAxZffJDCJdVfFTAyevu"; /* Hashedpart */ +if (blowfish_bcrypt_verify(cleartxtpassword, existinghashed)) + printf("Password is correct."); +else + printf("Password is incorrect."); +@end example +@end deftypefun + @subsection Camellia @cindex Camellia