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	md5block.c - 9base - revived minimalist port of Plan 9 userland to Unix
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	md5block.c (5015B)
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	1 #include "os.h"
	2 #include <libsec.h>
	3
	4 /*
	5 * rfc1321 requires that I include this. The code is new. The constan…
	6 * all come from the rfc (hence the copyright). We trade a table for t…
	7 * macros in rfc. The total size is a lot less. -- presotto
	8 *
	9 * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
	10 * rights reserved.
	11 *
	12 * License to copy and use this software is granted provided that…
	13 * is identified as the "RSA Data Security, Inc. MD5 Message-Dige…
	14 * Algorithm" in all material mentioning or referencing this soft…
	15 * or this function.
	16 *
	17 * License is also granted to make and use derivative works provi…
	18 * that such works are identified as "derived from the RSA Data
	19 * Security, Inc. MD5 Message-Digest Algorithm" in all material
	20 * mentioning or referencing the derived work.
	21 *
	22 * RSA Data Security, Inc. makes no representations concerning ei…
	23 * the merchantability of this software or the suitability of this
	24 * software forany particular purpose. It is provided "as is"
	25 * without express or implied warranty of any kind.
	26 * These notices must be retained in any copies of any part of th…
	27 * documentation and/or software.
	28 */
	29
	30 /*
	31 * Rotate ammounts used in the algorithm
	32 */
	33 enum
	34 {
	35 S11= 7,
	36 S12= 12,
	37 S13= 17,
	38 S14= 22,
	39
	40 S21= 5,
	41 S22= 9,
	42 S23= 14,
	43 S24= 20,
	44
	45 S31= 4,
	46 S32= 11,
	47 S33= 16,
	48 S34= 23,
	49
	50 S41= 6,
	51 S42= 10,
	52 S43= 15,
	53 S44= 21,
	54 };
	55
	56 static u32int md5tab[] =
	57 {
	58 /* round 1 */
	59 /[0]/ 0xd76aa478,
	60 0xe8c7b756,
	61 0x242070db,
	62 0xc1bdceee,
	63 0xf57c0faf,
	64 0x4787c62a,
	65 0xa8304613,
	66 0xfd469501,
	67 0x698098d8,
	68 0x8b44f7af,
	69 0xffff5bb1,
	70 0x895cd7be,
	71 0x6b901122,
	72 0xfd987193,
	73 0xa679438e,
	74 0x49b40821,
	75
	76 /* round 2 */
	77 /[16]/0xf61e2562,
	78 0xc040b340,
	79 0x265e5a51,
	80 0xe9b6c7aa,
	81 0xd62f105d,
	82 0x2441453,
	83 0xd8a1e681,
	84 0xe7d3fbc8,
	85 0x21e1cde6,
	86 0xc33707d6,
	87 0xf4d50d87,
	88 0x455a14ed,
	89 0xa9e3e905,
	90 0xfcefa3f8,
	91 0x676f02d9,
	92 0x8d2a4c8a,
	93
	94 /* round 3 */
	95 /[32]/0xfffa3942,
	96 0x8771f681,
	97 0x6d9d6122,
	98 0xfde5380c,
	99 0xa4beea44,
	100 0x4bdecfa9,
	101 0xf6bb4b60,
	102 0xbebfbc70,
	103 0x289b7ec6,
	104 0xeaa127fa,
	105 0xd4ef3085,
	106 0x4881d05,
	107 0xd9d4d039,
	108 0xe6db99e5,
	109 0x1fa27cf8,
	110 0xc4ac5665,
	111
	112 /* round 4 */
	113 /[48]/0xf4292244,
	114 0x432aff97,
	115 0xab9423a7,
	116 0xfc93a039,
	117 0x655b59c3,
	118 0x8f0ccc92,
	119 0xffeff47d,
	120 0x85845dd1,
	121 0x6fa87e4f,
	122 0xfe2ce6e0,
	123 0xa3014314,
	124 0x4e0811a1,
	125 0xf7537e82,
	126 0xbd3af235,
	127 0x2ad7d2bb,
	128 0xeb86d391,
	129 };
	130
	131 static void decode(u32int, uchar, ulong);
	132 extern void _md5block(uchar p, ulong len, u32int s);
	133
	134 void
	135 _md5block(uchar p, ulong len, u32int s)
	136 {
	137 u32int a, b, c, d, sh;
	138 u32int *t;
	139 uchar *end;
	140 u32int x[16];
	141
	142 for(end = p+len; p < end; p += 64){
	143 a = s[0];
	144 b = s[1];
	145 c = s[2];
	146 d = s[3];
	147
	148 decode(x, p, 64);
	149
	150 t = md5tab;
	151 sh = 0;
	152 for(; sh != 16; t += 4){
	153 a += ((c ^ d) & b) ^ d;
	154 a += x[sh] + t[0];
	155 a = (a << S11) \| (a >> (32 - S11));
	156 a += b;
	157
	158 d += ((b ^ c) & a) ^ c;
	159 d += x[sh + 1] + t[1];
	160 d = (d << S12) \| (d >> (32 - S12));
	161 d += a;
	162
	163 c += ((a ^ b) & d) ^ b;
	164 c += x[sh + 2] + t[2];
	165 c = (c << S13) \| (c >> (32 - S13));
	166 c += d;
	167
	168 b += ((d ^ a) & c) ^ a;
	169 b += x[sh + 3] + t[3];
	170 b = (b << S14) \| (b >> (32 - S14));
	171 b += c;
	172
	173 sh += 4;
	174 }
	175 sh = 1;
	176 for(; sh != 1+20*4; t += 4){
	177 a += ((b ^ c) & d) ^ c;
	178 a += x[sh & 0xf] + t[0];
	179 a = (a << S21) \| (a >> (32 - S21));
	180 a += b;
	181
	182 d += ((a ^ b) & c) ^ b;
	183 d += x[(sh + 5) & 0xf] + t[1];
	184 d = (d << S22) \| (d >> (32 - S22));
	185 d += a;
	186
	187 c += ((d ^ a) & b) ^ a;
	188 c += x[(sh + 10) & 0xf] + t[2];
	189 c = (c << S23) \| (c >> (32 - S23));
	190 c += d;
	191
	192 b += ((c ^ d) & a) ^ d;
	193 b += x[(sh + 15) & 0xf] + t[3];
	194 b = (b << S24) \| (b >> (32 - S24));
	195 b += c;
	196
	197 sh += 20;
	198 }
	199 sh = 5;
	200 for(; sh != 5+12*4; t += 4){
	201 a += b ^ c ^ d;
	202 a += x[sh & 0xf] + t[0];
	203 a = (a << S31) \| (a >> (32 - S31));
	204 a += b;
	205
	206 d += a ^ b ^ c;
	207 d += x[(sh + 3) & 0xf] + t[1];
	208 d = (d << S32) \| (d >> (32 - S32));
	209 d += a;
	210
	211 c += d ^ a ^ b;
	212 c += x[(sh + 6) & 0xf] + t[2];
	213 c = (c << S33) \| (c >> (32 - S33));
	214 c += d;
	215
	216 b += c ^ d ^ a;
	217 b += x[(sh + 9) & 0xf] + t[3];
	218 b = (b << S34) \| (b >> (32 - S34));
	219 b += c;
	220
	221 sh += 12;
	222 }
	223 sh = 0;
	224 for(; sh != 28*4; t += 4){
	225 a += c ^ (b \| ~d);
	226 a += x[sh & 0xf] + t[0];
	227 a = (a << S41) \| (a >> (32 - S41));
	228 a += b;
	229
	230 d += b ^ (a \| ~c);
	231 d += x[(sh + 7) & 0xf] + t[1];
	232 d = (d << S42) \| (d >> (32 - S42));
	233 d += a;
	234
	235 c += a ^ (d \| ~b);
	236 c += x[(sh + 14) & 0xf] + t[2];
	237 c = (c << S43) \| (c >> (32 - S43));
	238 c += d;
	239
	240 b += d ^ (c \| ~a);
	241 b += x[(sh + 21) & 0xf] + t[3];
	242 b = (b << S44) \| (b >> (32 - S44));
	243 b += c;
	244
	245 sh += 28;
	246 }
	247
	248 s[0] += a;
	249 s[1] += b;
	250 s[2] += c;
	251 s[3] += d;
	252 }
	253 }
	254
	255 /*
	256 * decodes input (uchar) into output (u32int). Assumes len is
	257 * a multiple of 4.
	258 */
	259 static void
	260 decode(u32int output, uchar input, ulong len)
	261 {
	262 uchar *e;
	263
	264 for(e = input+len; input < e; input += 4)
	265 *output++ = input[0] \| (input[1] << 8) \|
	266 (input[2] << 16) \| (input[3] << 24);
	267 }