Embedded systems coursework 2.
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MD5.cpp
- Committer:
- feb11
- Date:
- 2013-09-12
- Revision:
- 6:19aa835f2bbb
- Parent:
- 5:06cd9c8afa0b
File content as of revision 6:19aa835f2bbb:
/** 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; }