hash - Implementation of MD5 in C -
i want implement md5 hashing function in c project, , want make own, because 1 thing afraid of using else's code (mainly because have trouble understanding such codes). so, headed straight wiki page pseudocode: http://en.wikipedia.org/wiki/md5 decided leave padding , breaking 512 bit chunks stuff later , start md5 hash of empty string. padded, should (i think) this:
unsigned int message[16] = {0x80000000, 0x00000000, 0x00000000, 0x00000000,//binary: 100000000000000000000000... 0x00000000, 0x00000000, 0x00000000, 0x00000000,// ...0000000000000000000000000000... 0x00000000, 0x00000000, 0x00000000, 0x00000000,// ...0000000000000000000000000000... 0x00000000, 0x00000000, 0x00000000, 0x00000000};//...0000000000000000000000000000000 and here how reproduced wiki's main loop (the 1 deals 1 512-bit chunk) in c:
unsigned int a0, b0, c0, d0, a, b, c, d, i, f, g, bufd; //empty string appended 1 bit , zeroes till 512 bytes long 16 32-bit words unsigned int message[16] = {0x80000000, 0x00000000, 0x00000000, 0x00000000,//binary: 100000000000000000000000... 0x00000000, 0x00000000, 0x00000000, 0x00000000,// ...0000000000000000000000000000... 0x00000000, 0x00000000, 0x00000000, 0x00000000,// ...0000000000000000000000000000... 0x00000000, 0x00000000, 0x00000000, 0x00000000};//...0000000000000000000000000000000 unsigned int shiftamounts[64] = {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}; unsigned int partsofsines[64] = {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}; a0 = 0x67452301; b0 = 0xefcdab89; c0 = 0x98badcfe; d0 = 0x10325476; //gotta put loop each 512-bit chunk = a0; b = b0; c = c0; d = d0; (i=0; i<64; i++){ if (i < 16){ f = (b & c) | (~b & d); g = i; } else if (i >= 16 && < 32){ f = (d & b) | (~d & c); g = (5*i + 1) % 16; } else if (i >= 32 && < 48){ f = b ^ c ^ d; g = (3*i + 5) % 16; } else if (i >= 48){ f = c ^ (b | ~d); g = (7*i) % 16; } bufd = d; d = c; c = b; b += leftrotate((a + f + partsofsines[i] + message[g]), shiftamounts[i]); = bufd; } a0 += a; b0 += b; c0 += c; d0 += d; //end future loop printf ("a0=%u, b0=%u, c0=%u, d0=%u", a0, b0, c0, d0); the leftrotate function, modified pseudocode on wikipedia:
unsigned int leftrotate(unsigned int x, int n){ return ((x) << n) | ((x) >> (32 - n)); } this outputs following:
a0=578518856, b0=3524428790, c0=1003076545, d0=1531243034 converting these decimal values hex, following:
a0 = 578518856 -> 227b7f48 b0 = 3524428790 -> d21283f6 c0 = 1003076545 -> 3bc9bbc1 d0 = 1531243034 -> 5b44ea1a which isn't bit similar actual md5 digest of empty string (which d41d8cd98f00b204e9800998ecf8427e). so, question is, going wrong?
#include <stdio.h> //empty string appended 1 bit , zeroes till 512 bytes long 16 32-bit words unsigned int message[16] = {0x00000080, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000}; unsigned int shiftamounts[64] = {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}; unsigned int partsofsines[64] = {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}; unsigned leftrotate(unsigned x, int n) { return (x << n) | (x >> (32 - n)); } void printreverseendian(unsigned n) { printf("%02x%02x%02x%02x", n & 0xff, (n >> 8) & 0xff, (n >> 16) & 0xff, n >> 24); } int main() { unsigned int a0, b0, c0, d0, a, b, c, d, i, f, g, bufd; a0 = 0x67452301; b0 = 0xefcdab89; c0 = 0x98badcfe; d0 = 0x10325476; = a0; b = b0; c = c0; d = d0; (i=0; i<64; i++){ if (i < 16){ f = (b & c) | (~b & d); g = i; } else if (i < 32){ f = (d & b) | (~d & c); g = (5*i + 1) % 16; } else if (i < 48){ f = b ^ c ^ d; g = (3*i + 5) % 16; } else { f = c ^ (b | ~d); g = (7*i) % 16; } bufd = d; d = c; c = b; b += leftrotate((a + f + partsofsines[i] + message[g]), shiftamounts[i]); = bufd; } a0 += a; b0 += b; c0 += c; d0 += d; printreverseendian(a0); printreverseendian(b0); printreverseendian(c0); printreverseendian(d0); return 0; }
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