Средства и методы разработки

MD5 занимает 2 Кбайта памяти программ на Cortex-M3. Ужать в 2 раза будет точно невозможно, потому что около 1 Кбайта занимают только константы. UPD: вру, ужимал же, и оно ужалось до 1 Кбайта: https://github.com/markokr/pghashlib/blob/master/src/md5.c
/* * MD5 implementation based on RFC1321. * * Copyright (c) 2008 Marko Kreen, Skype * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "md5.h" #include <stdint.h> #include <string.h> #define MD5_BLOCK_LENGTH 64 #define MD5_DIGEST_LENGTH 16 struct md5_ctx { uint32_t nbytes; uint32_t a[4]; uint32_t buf[16]; }; /* * Support functions. */ #define bufpos(ctx) ((ctx)->nbytes & (MD5_BLOCK_LENGTH - 1)) static inline uint32_t swap32(uint32_t x) { #if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3))) return __builtin_bswap32(x); #else x = ((x << 8) & 0xFF00FF00) | ((x >> 8) & 0x00FF00FF); return (x << 16) | (x >> 16); #endif } static inline void swap_words(uint32_t *w, int n) { #ifdef WORDS_BIGENDIAN for (; n > 0; w++, n--) *w = swap32(*w); #endif } static inline uint32_t rol32(uint32_t v, int s) { return (v << s) | (v >> (32 - s)); } /* * MD5 core. */ #define F(X,Y,Z) ((X & Y) | ((~X) & Z)) #define G(X,Y,Z) ((X & Z) | (Y & (~Z))) #define H(X,Y,Z) (X ^ Y ^ Z) #define I(X,Y,Z) (Y ^ (X | (~Z))) static void md5_mix(struct md5_ctx *ctx, const uint32_t *X) { static const uint8_t k1[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12, 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2, 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 }; static const uint32_t k2[] = { 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21 }; static const uint32_t k3[] = { 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 }; uint32_t a[4]; memcpy(a, &ctx->a, sizeof a); for (int i = 0; i < 64; i++) { int j = (64 - i) & 3; uint32_t b = a[(j + 1) & 3], c = a[(j + 2) & 3], d = a[(j + 3) & 3], tmp; switch (i / 16) { case 0: tmp = F(b, c, d); break; case 1: tmp = G(b, c, d); break; case 2: tmp = H(b, c, d); break; case 3: tmp = I(b, c, d); break; } a[j] = b + rol32(a[j] + tmp + X[k1[i]] + k3[i], k2[i]); } for (int i = 0; i < 4; i++) { ctx->a[i] += a[i]; } } /* * Public API. */ static void md5_reset(struct md5_ctx *ctx) { static const uint32_t init[] = { 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476 }; ctx->nbytes = 0; memcpy(ctx->a, init, sizeof init); } static void md5_update(struct md5_ctx *ctx, const void *data, unsigned int len) { unsigned int n; const uint8_t *ptr = data; uint8_t *buf = (uint8_t *)ctx->buf; while (len > 0) { n = MD5_BLOCK_LENGTH - bufpos(ctx); if (n > len) n = len; memcpy(buf + bufpos(ctx), ptr, n); ptr += n; len -= n; ctx->nbytes += n; if (bufpos(ctx) == 0) { swap_words(ctx->buf, 16); md5_mix(ctx, ctx->buf); } } } static void md5_final(struct md5_ctx *ctx, void *dst) { static uint8_t padding[MD5_BLOCK_LENGTH] = { 0x80 }; uint32_t final_len = ctx->nbytes * 8; int pad_len, pos = bufpos(ctx); /* add padding */ pad_len = MD5_BLOCK_LENGTH - 8 - pos; if (pad_len <= 0) pad_len += MD5_BLOCK_LENGTH; md5_update(ctx, padding, pad_len); /* add length directly */ swap_words(ctx->buf, 14); ctx->buf[14] = final_len; ctx->buf[15] = 0; /* final result */ md5_mix(ctx, ctx->buf); swap_words(ctx->a, 4); memcpy(dst, &ctx->a, 16); } void md5(const void *data, size_t len, void *result) { struct md5_ctx ctx; md5_reset(&ctx); md5_update(&ctx, data, len); md5_final(&ctx, result); }