Embedded systems coursework 2.
Fork of Crypto_light by
Diff: hash/MD5.cpp
- Revision:
- 7:2dbbdfb08123
- Parent:
- 6:19aa835f2bbb
- Child:
- 10:bc9c23aa3870
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hash/MD5.cpp Sat Sep 14 18:21:32 2013 +0000 @@ -0,0 +1,198 @@ +/** + Implementation of MD5 as described here: + http://tools.ietf.org/html/rfc1321 +*/ + +#include "MD5.h" +#include <string.h> + +static const uint32_t A = 0x67452301; +static const uint32_t B = 0xefcdab89; +static const uint32_t C = 0x98badcfe; +static const uint32_t D = 0x10325476; + + +#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 ROTL(W,N) (((W) << N) | ((W) >> (32-N))) + +#define ROUND1(a,b,c,d,x,s,t) \ + a = ROTL(a + F(b,c,d) + x + t,s) + b; + +#define ROUND2(a,b,c,d,x,s,t) \ + a = ROTL(a + G(b,c,d) + x + t,s) + b; + +#define ROUND3(a,b,c,d,x,s,t) \ + a = ROTL(a + H(b,c,d) + x + t,s) + b; + +#define ROUND4(a,b,c,d,x,s,t) \ + a = ROTL(a + I(b,c,d) + x + t,s) + b; + + + +MD5::MD5(): +HashAlgorithm(), +a(A), +b(B), +c(C), +d(D), +totalBufferLength(0), +buffer(), +bufferLength(0) +{ +} + +uint8_t MD5::outputSize() const +{ + return 16; +} + +void MD5::update(uint8_t *data, uint32_t length) +{ + if(length < 64-bufferLength) + { + memcpy(&buffer[bufferLength], data, length); + bufferLength += length; + totalBufferLength += length; + return; + } + int offset = 64-bufferLength; + memcpy(&buffer[bufferLength], data, offset); + computeRounds(&a, &b, &c, &d, buffer); + while(length-offset > 64) + { + memcpy(buffer, &data[offset], 64); + computeRounds(&a, &b, &c, &d, buffer); + offset += 64; + } + if(offset > length) + offset -= 64; + bufferLength = length - offset; + memcpy(buffer, &data[offset], bufferLength); + totalBufferLength += length; +} + +void MD5::finalize(uint8_t *hash) +{ + uint32_t *hash2 = (uint32_t*)hash; + uint16_t padding; + if(totalBufferLength % 64 < 56) + padding = 56 - (totalBufferLength % 64); + else + padding = 56 + (64 - (totalBufferLength % 64)); + buffer[bufferLength++] = 0x80; + padding--; + if(padding+bufferLength == 56) + memset(&buffer[bufferLength], 0, padding); + else + { + memset(&buffer[bufferLength], 0, 64-bufferLength); + computeRounds(&a, &b, &c, &d, buffer); + memset(buffer, 0, 56); + } + uint64_t lengthBit = totalBufferLength << 3; + uint32_t lengthBitLow = lengthBit; + uint32_t lengthBitHigh = lengthBit >> 32; + memcpy(&buffer[56], &lengthBitLow, 4); + memcpy(&buffer[60], &lengthBitHigh, 4); + computeRounds(&a, &b, &c, &d, buffer); + + hash2[0] = a; + hash2[1] = b; + hash2[2] = c; + hash2[3] = d; + // reset state + a = A; + b = B; + c = C; + d = D; + totalBufferLength = 0; + bufferLength = 0; +} + + +void MD5::computeHash(uint8_t *hash, uint8_t *data, uint32_t length) +{ + uint32_t *hash2 = (uint32_t*)hash; + uint64_t lengthBit = length << 3; + uint16_t padding; + if(length % 64 < 56) + padding = 56 - (length % 64); + else + padding = 56 + (64 - (length % 64)); + + uint32_t a = A, b = B, c = C, d = D; + while(length >= 64) + { + computeRounds(&a, &b, &c, &d, data); + data += 64; + length -= 64; + } + uint8_t buffer[64]; + memcpy(buffer, data, length); + buffer[length++] = 0x80; + padding--; + if(padding+length == 56) + memset(&buffer[length], 0, padding); + else + { + memset(&buffer[length], 0, 64-length); + computeRounds(&a, &b, &c, &d, data); + memset(buffer, 0, 56); + } + + uint32_t lengthBitLow = lengthBit; + uint32_t lengthBitHigh = lengthBit >> 32; + memcpy(&buffer[56], &lengthBitLow, 4); + memcpy(&buffer[60], &lengthBitHigh, 4); + + computeRounds(&a, &b, &c, &d, buffer); + + hash2[0] = a; + hash2[1] = b; + hash2[2] = c; + hash2[3] = d; +} + +void MD5::computeRounds(uint32_t *a2, uint32_t *b2, uint32_t *c2, uint32_t *d2, uint8_t *buffer) +{ + uint32_t a = *a2, b = *b2, c = *c2, d = *d2; + uint32_t tmpA = a, tmpB = b, tmpC = c, tmpD = d; + + uint32_t *x = (uint32_t*)buffer; + + // Round 1 + ROUND1(a,b,c,d,x[0],7,0xd76aa478); ROUND1(d,a,b,c,x[1],12,0xe8c7b756); ROUND1(c,d,a,b,x[2],17,0x242070db); ROUND1(b,c,d,a,x[3],22,0xc1bdceee); + ROUND1(a,b,c,d,x[4],7,0xf57c0faf); ROUND1(d,a,b,c,x[5],12,0x4787c62a); ROUND1(c,d,a,b,x[6],17,0xa8304613); ROUND1(b,c,d,a,x[7],22,0xfd469501); + ROUND1(a,b,c,d,x[8],7,0x698098d8); ROUND1(d,a,b,c,x[9],12,0x8b44f7af); ROUND1(c,d,a,b,x[10],17,0xffff5bb1); ROUND1(b,c,d,a,x[11],22,0x895cd7be); + ROUND1(a,b,c,d,x[12],7,0x6b901122); ROUND1(d,a,b,c,x[13],12,0xfd987193); ROUND1(c,d,a,b,x[14],17,0xa679438e); ROUND1(b,c,d,a,x[15],22,0x49b40821); + + + // Round 2 + ROUND2(a,b,c,d,x[1],5,0xf61e2562); ROUND2(d,a,b,c,x[6],9,0xc040b340); ROUND2(c,d,a,b,x[11],14,0x265e5a51); ROUND2(b,c,d,a,x[0],20,0xe9b6c7aa); + ROUND2(a,b,c,d,x[5],5,0xd62f105d); ROUND2(d,a,b,c,x[10],9,0x02441453); ROUND2(c,d,a,b,x[15],14,0xd8a1e681); ROUND2(b,c,d,a,x[4],20,0xe7d3fbc8); + ROUND2(a,b,c,d,x[9],5,0x21e1cde6); ROUND2(d,a,b,c,x[14],9,0xc33707d6); ROUND2(c,d,a,b,x[3],14,0xf4d50d87); ROUND2(b,c,d,a,x[8],20,0x455a14ed); + ROUND2(a,b,c,d,x[13],5,0xa9e3e905); ROUND2(d,a,b,c,x[2],9,0xfcefa3f8); ROUND2(c,d,a,b,x[7],14,0x676f02d9); ROUND2(b,c,d,a,x[12],20,0x8d2a4c8a); + + + // Round 3 + ROUND3(a,b,c,d,x[5],4,0xfffa3942); ROUND3(d,a,b,c,x[8],11,0x8771f681); ROUND3(c,d,a,b,x[11],16,0x6d9d6122); ROUND3(b,c,d,a,x[14],23,0xfde5380c); + ROUND3(a,b,c,d,x[1],4,0xa4beea44); ROUND3(d,a,b,c,x[4],11,0x4bdecfa9); ROUND3(c,d,a,b,x[7],16,0xf6bb4b60); ROUND3(b,c,d,a,x[10],23,0xbebfbc70); + ROUND3(a,b,c,d,x[13],4,0x289b7ec6); ROUND3(d,a,b,c,x[0],11,0xeaa127fa); ROUND3(c,d,a,b,x[3],16,0xd4ef3085); ROUND3(b,c,d,a,x[6],23,0x04881d05); + ROUND3(a,b,c,d,x[9],4,0xd9d4d039); ROUND3(d,a,b,c,x[12],11,0xe6db99e5); ROUND3(c,d,a,b,x[15],16,0x1fa27cf8); ROUND3(b,c,d,a,x[2],23,0xc4ac5665); + + + // Round 4 + ROUND4(a,b,c,d,x[0],6,0xf4292244); ROUND4(d,a,b,c,x[7],10,0x432aff97); ROUND4(c,d,a,b,x[14],15,0xab9423a7); ROUND4(b,c,d,a,x[5],21,0xfc93a039); + ROUND4(a,b,c,d,x[12],6,0x655b59c3); ROUND4(d,a,b,c,x[3],10,0x8f0ccc92); ROUND4(c,d,a,b,x[10],15,0xffeff47d); ROUND4(b,c,d,a,x[1],21,0x85845dd1); + ROUND4(a,b,c,d,x[8],6,0x6fa87e4f); ROUND4(d,a,b,c,x[15],10,0xfe2ce6e0); ROUND4(c,d,a,b,x[6],15,0xa3014314); ROUND4(b,c,d,a,x[13],21,0x4e0811a1); + ROUND4(a,b,c,d,x[4],6,0xf7537e82); ROUND4(d,a,b,c,x[11],10,0xbd3af235); ROUND4(c,d,a,b,x[2],15,0x2ad7d2bb); ROUND4(b,c,d,a,x[9],21,0xeb86d391); + + *a2 = a + tmpA; + *b2 = b + tmpB; + *c2 = c + tmpC; + *d2 = d + tmpD; +}