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+/*********************************************************************
+* Filename: md5.c
+* Author: Brad Conte (brad AT bradconte.com)
+* Copyright:
+* Disclaimer: This code is presented "as is" without any guarantees.
+* Details: Implementation of the MD5 hashing algorithm.
+ Algorithm specification can be found here:
+ * http://tools.ietf.org/html/rfc1321
+ This implementation uses little endian byte order.
+*********************************************************************/
+
+/*************************** HEADER FILES ***************************/
+#include <stdlib.h>
+#include <memory.h>
+#include "md5.h"
+
+/****************************** MACROS ******************************/
+#define ROTLEFT(a,b) ((a << b) | (a >> (32-b)))
+
+#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))
+
+#define FF(a,b,c,d,m,s,t) { a += F(b,c,d) + m + t; \
+ a = b + ROTLEFT(a,s); }
+#define GG(a,b,c,d,m,s,t) { a += G(b,c,d) + m + t; \
+ a = b + ROTLEFT(a,s); }
+#define HH(a,b,c,d,m,s,t) { a += H(b,c,d) + m + t; \
+ a = b + ROTLEFT(a,s); }
+#define II(a,b,c,d,m,s,t) { a += I(b,c,d) + m + t; \
+ a = b + ROTLEFT(a,s); }
+
+/*********************** FUNCTION DEFINITIONS ***********************/
+void md5_transform(MD5_CTX *ctx, const BYTE data[])
+{
+ WORD a, b, c, d, m[16], i, j;
+
+ // MD5 specifies big endian byte order, but this implementation assumes a little
+ // endian byte order CPU. Reverse all the bytes upon input, and re-reverse them
+ // on output (in md5_final()).
+ for (i = 0, j = 0; i < 16; ++i, j += 4)
+ m[i] = (data[j]) + (data[j + 1] << 8) + (data[j + 2] << 16) + (data[j + 3] << 24);
+
+ a = ctx->state[0];
+ b = ctx->state[1];
+ c = ctx->state[2];
+ d = ctx->state[3];
+
+ FF(a,b,c,d,m[0], 7,0xd76aa478);
+ FF(d,a,b,c,m[1], 12,0xe8c7b756);
+ FF(c,d,a,b,m[2], 17,0x242070db);
+ FF(b,c,d,a,m[3], 22,0xc1bdceee);
+ FF(a,b,c,d,m[4], 7,0xf57c0faf);
+ FF(d,a,b,c,m[5], 12,0x4787c62a);
+ FF(c,d,a,b,m[6], 17,0xa8304613);
+ FF(b,c,d,a,m[7], 22,0xfd469501);
+ FF(a,b,c,d,m[8], 7,0x698098d8);
+ FF(d,a,b,c,m[9], 12,0x8b44f7af);
+ FF(c,d,a,b,m[10],17,0xffff5bb1);
+ FF(b,c,d,a,m[11],22,0x895cd7be);
+ FF(a,b,c,d,m[12], 7,0x6b901122);
+ FF(d,a,b,c,m[13],12,0xfd987193);
+ FF(c,d,a,b,m[14],17,0xa679438e);
+ FF(b,c,d,a,m[15],22,0x49b40821);
+
+ GG(a,b,c,d,m[1], 5,0xf61e2562);
+ GG(d,a,b,c,m[6], 9,0xc040b340);
+ GG(c,d,a,b,m[11],14,0x265e5a51);
+ GG(b,c,d,a,m[0], 20,0xe9b6c7aa);
+ GG(a,b,c,d,m[5], 5,0xd62f105d);
+ GG(d,a,b,c,m[10], 9,0x02441453);
+ GG(c,d,a,b,m[15],14,0xd8a1e681);
+ GG(b,c,d,a,m[4], 20,0xe7d3fbc8);
+ GG(a,b,c,d,m[9], 5,0x21e1cde6);
+ GG(d,a,b,c,m[14], 9,0xc33707d6);
+ GG(c,d,a,b,m[3], 14,0xf4d50d87);
+ GG(b,c,d,a,m[8], 20,0x455a14ed);
+ GG(a,b,c,d,m[13], 5,0xa9e3e905);
+ GG(d,a,b,c,m[2], 9,0xfcefa3f8);
+ GG(c,d,a,b,m[7], 14,0x676f02d9);
+ GG(b,c,d,a,m[12],20,0x8d2a4c8a);
+
+ HH(a,b,c,d,m[5], 4,0xfffa3942);
+ HH(d,a,b,c,m[8], 11,0x8771f681);
+ HH(c,d,a,b,m[11],16,0x6d9d6122);
+ HH(b,c,d,a,m[14],23,0xfde5380c);
+ HH(a,b,c,d,m[1], 4,0xa4beea44);
+ HH(d,a,b,c,m[4], 11,0x4bdecfa9);
+ HH(c,d,a,b,m[7], 16,0xf6bb4b60);
+ HH(b,c,d,a,m[10],23,0xbebfbc70);
+ HH(a,b,c,d,m[13], 4,0x289b7ec6);
+ HH(d,a,b,c,m[0], 11,0xeaa127fa);
+ HH(c,d,a,b,m[3], 16,0xd4ef3085);
+ HH(b,c,d,a,m[6], 23,0x04881d05);
+ HH(a,b,c,d,m[9], 4,0xd9d4d039);
+ HH(d,a,b,c,m[12],11,0xe6db99e5);
+ HH(c,d,a,b,m[15],16,0x1fa27cf8);
+ HH(b,c,d,a,m[2], 23,0xc4ac5665);
+
+ II(a,b,c,d,m[0], 6,0xf4292244);
+ II(d,a,b,c,m[7], 10,0x432aff97);
+ II(c,d,a,b,m[14],15,0xab9423a7);
+ II(b,c,d,a,m[5], 21,0xfc93a039);
+ II(a,b,c,d,m[12], 6,0x655b59c3);
+ II(d,a,b,c,m[3], 10,0x8f0ccc92);
+ II(c,d,a,b,m[10],15,0xffeff47d);
+ II(b,c,d,a,m[1], 21,0x85845dd1);
+ II(a,b,c,d,m[8], 6,0x6fa87e4f);
+ II(d,a,b,c,m[15],10,0xfe2ce6e0);
+ II(c,d,a,b,m[6], 15,0xa3014314);
+ II(b,c,d,a,m[13],21,0x4e0811a1);
+ II(a,b,c,d,m[4], 6,0xf7537e82);
+ II(d,a,b,c,m[11],10,0xbd3af235);
+ II(c,d,a,b,m[2], 15,0x2ad7d2bb);
+ II(b,c,d,a,m[9], 21,0xeb86d391);
+
+ ctx->state[0] += a;
+ ctx->state[1] += b;
+ ctx->state[2] += c;
+ ctx->state[3] += d;
+}
+
+void md5_init(MD5_CTX *ctx)
+{
+ ctx->datalen = 0;
+ ctx->bitlen = 0;
+ ctx->state[0] = 0x67452301;
+ ctx->state[1] = 0xEFCDAB89;
+ ctx->state[2] = 0x98BADCFE;
+ ctx->state[3] = 0x10325476;
+}
+
+void md5_update(MD5_CTX *ctx, const BYTE data[], size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len; ++i) {
+ ctx->data[ctx->datalen] = data[i];
+ ctx->datalen++;
+ if (ctx->datalen == 64) {
+ md5_transform(ctx, ctx->data);
+ ctx->bitlen += 512;
+ ctx->datalen = 0;
+ }
+ }
+}
+
+void md5_final(MD5_CTX *ctx, BYTE hash[])
+{
+ size_t i;
+
+ i = ctx->datalen;
+
+ // Pad whatever data is left in the buffer.
+ if (ctx->datalen < 56) {
+ ctx->data[i++] = 0x80;
+ while (i < 56)
+ ctx->data[i++] = 0x00;
+ }
+ else if (ctx->datalen >= 56) {
+ ctx->data[i++] = 0x80;
+ while (i < 64)
+ ctx->data[i++] = 0x00;
+ md5_transform(ctx, ctx->data);
+ memset(ctx->data, 0, 56);
+ }
+
+ // Append to the padding the total message's length in bits and transform.
+ ctx->bitlen += ctx->datalen * 8;
+ ctx->data[56] = ctx->bitlen;
+ ctx->data[57] = ctx->bitlen >> 8;
+ ctx->data[58] = ctx->bitlen >> 16;
+ ctx->data[59] = ctx->bitlen >> 24;
+ ctx->data[60] = ctx->bitlen >> 32;
+ ctx->data[61] = ctx->bitlen >> 40;
+ ctx->data[62] = ctx->bitlen >> 48;
+ ctx->data[63] = ctx->bitlen >> 56;
+ md5_transform(ctx, ctx->data);
+
+ // Since this implementation uses little endian byte ordering and MD uses big endian,
+ // reverse all the bytes when copying the final state to the output hash.
+ for (i = 0; i < 4; ++i) {
+ hash[i] = (ctx->state[0] >> (i * 8)) & 0x000000ff;
+ hash[i + 4] = (ctx->state[1] >> (i * 8)) & 0x000000ff;
+ hash[i + 8] = (ctx->state[2] >> (i * 8)) & 0x000000ff;
+ hash[i + 12] = (ctx->state[3] >> (i * 8)) & 0x000000ff;
+ }
+}