Embedded systems coursework 2.
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Diff: hash/SHA1.cpp
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- 7:2dbbdfb08123
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hash/SHA1.cpp Sat Sep 14 18:21:32 2013 +0000 @@ -0,0 +1,221 @@ +/** + Implementation of SHA-1 as described here: + http://tools.ietf.org/html/rfc1319 +*/ + +#include "SHA1.h" +#include <string.h> +#include <stdio.h> +#include <stdlib.h> + +#define F0(B,C,D) ((B & C) | ((~B) & D)) +#define F1(B,C,D) (B ^ C ^ D) +#define F2(B,C,D) ((B & C) | (B & D) | (C & D)) +#define ROTL(W,N) (((W) << N) | ((W) >> (32-N))) + +static const uint32_t K0 = 0x5A827999; +static const uint32_t K1 = 0x6ED9EBA1; +static const uint32_t K2 = 0x8F1BBCDC; +static const uint32_t K3 = 0xCA62C1D6; + + +static const uint32_t H0 = 0x67452301; +static const uint32_t H1 = 0xEFCDAB89; +static const uint32_t H2 = 0x98BADCFE; +static const uint32_t H3 = 0x10325476; +static const uint32_t H4 = 0xC3D2E1F0; + +static const uint32_t MASK = 0xF; + +#define W(s) ( w[s] = ROTL(w[((s) + 13) & MASK] ^ w[((s) + 8) & MASK] ^ w[((s) + 2) & MASK] ^ w[s],1)) + +#define R0(A,B,C,D,E,T) E += ROTL(A, 5) + F0(B, C, D) + w[T] + K0; \ + B = ROTL(B,30); +#define R1(A,B,C,D,E,T) E += ROTL(A, 5) + F0(B, C, D) + W(T & MASK) + K0; \ + B = ROTL(B,30); +#define R2(A,B,C,D,E,T) E += ROTL(A, 5) + F1(B, C, D) + W(T & MASK) + K1; \ + B = ROTL(B,30); +#define R3(A,B,C,D,E,T) E += ROTL(A, 5) + F2(B, C, D) + W(T & MASK) + K2; \ + B = ROTL(B,30); +#define R4(A,B,C,D,E,T) E += ROTL(A, 5) + F1(B, C, D) + W(T & MASK) + K3; \ + B = ROTL(B,30); + + +SHA1::SHA1(): +HashAlgorithm(), +h0(H0), +h1(H1), +h2(H2), +h3(H3), +h4(H4), +totalBufferLength(0), +buffer(), +bufferLength(0) +{ +} + +uint8_t SHA1::outputSize() const +{ + return 20; +} + +void SHA1::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); + computeBlock(&h0,&h1,&h2,&h3,&h4, buffer); + while(length-offset > 64) + { + memcpy(buffer, &data[offset], 64); + computeBlock(&h0,&h1,&h2,&h3,&h4, buffer); + offset += 64; + } + if(offset > length) + offset -= 64; + bufferLength = length - offset; + memcpy(buffer, &data[offset], bufferLength); + totalBufferLength += length; +} + +void SHA1::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); + computeBlock(&h0,&h1,&h2,&h3,&h4, buffer); + memset(buffer, 0, 56); + } + + uint64_t lengthBit = totalBufferLength << 3; + uint32_t lengthBitLow = lengthBit; + uint32_t lengthBitHigh = lengthBit >> 32; + lengthBitLow = __rev(lengthBitLow); + lengthBitHigh = __rev(lengthBitHigh); + memcpy(&buffer[56], &lengthBitHigh, 4); + memcpy(&buffer[60], &lengthBitLow, 4); + computeBlock(&h0,&h1,&h2,&h3,&h4, buffer); + + hash2[0] = __rev(h0); + hash2[1] = __rev(h1); + hash2[2] = __rev(h2); + hash2[3] = __rev(h3); + hash2[4] = __rev(h4); + + // reset state + h0 = H0; + h1 = H1; + h2 = H2; + h3 = H3; + h4 = H4; + totalBufferLength = 0; + bufferLength = 0; +} + + +void SHA1::computeHash(uint8_t *hash, uint8_t *data, uint32_t length) +{ + uint32_t *hash2 = (uint32_t*)hash; + uint64_t lengthBit = length << 3; + uint32_t padding; + if(length % 64 < 56) + padding = 56 - (length % 64); + else + padding = 56 + (64 - (length % 64)); + + uint32_t h0 = H0, h1 = H1, h2 = H2, h3 = H3, h4 = H4; + while(length >= 64) + { + computeBlock(&h0,&h1,&h2,&h3,&h4, data); + length -= 64; + data += 64; + } + + uint8_t buffer[64]; + memcpy(buffer, data, length); + buffer[length++] = 0x80; + padding--; + if(padding+length+8 == 64) + memset(&buffer[length], 0, padding); + else + { + memset(&buffer[length], 0, 64-length); + computeBlock(&h0,&h1,&h2,&h3,&h4, buffer); + memset(buffer, 0, 56); + } + + uint32_t lengthBitLow = lengthBit; + uint32_t lengthBitHigh = lengthBit >> 32; + lengthBitLow = __rev(lengthBitLow); + lengthBitHigh = __rev(lengthBitHigh); + memcpy(&buffer[60], &lengthBitLow, 4); + memcpy(&buffer[56], &lengthBitHigh, 4); + + computeBlock(&h0,&h1,&h2,&h3,&h4, buffer); + + hash2[0] = __rev(h0); + hash2[1] = __rev(h1); + hash2[2] = __rev(h2); + hash2[3] = __rev(h3); + hash2[4] = __rev(h4); +} + +void SHA1::computeBlock(uint32_t *h02, uint32_t *h12, uint32_t *h22, uint32_t *h32, uint32_t *h42, uint8_t *buffer) +{ + uint32_t *buffer2 = (uint32_t*)buffer; + uint32_t w[16]; + for(int t = 0; t < 16; ++t) + w[t] = __rev(buffer2[t]); + + uint32_t a = *h02, b = *h12, c = *h22, d = *h32, e = *h42; + + R0(a,b,c,d,e, 0) R0(e,a,b,c,d, 1) R0(d,e,a,b,c, 2) R0(c,d,e,a,b, 3) + R0(b,c,d,e,a, 4) R0(a,b,c,d,e, 5) R0(e,a,b,c,d, 6) R0(d,e,a,b,c, 7) + R0(c,d,e,a,b, 8) R0(b,c,d,e,a, 9) R0(a,b,c,d,e,10) R0(e,a,b,c,d,11) + R0(d,e,a,b,c,12) R0(c,d,e,a,b,13) R0(b,c,d,e,a,14) R0(a,b,c,d,e,15) + R1(e,a,b,c,d,16) R1(d,e,a,b,c,17) R1(c,d,e,a,b,18) R1(b,c,d,e,a,19) + + + R2(a,b,c,d,e,20) R2(e,a,b,c,d,21) R2(d,e,a,b,c,22) R2(c,d,e,a,b,23) + R2(b,c,d,e,a,24) R2(a,b,c,d,e,25) R2(e,a,b,c,d,26) R2(d,e,a,b,c,27) + R2(c,d,e,a,b,28) R2(b,c,d,e,a,29) R2(a,b,c,d,e,30) R2(e,a,b,c,d,31) + R2(d,e,a,b,c,32) R2(c,d,e,a,b,33) R2(b,c,d,e,a,34) R2(a,b,c,d,e,35) + R2(e,a,b,c,d,36) R2(d,e,a,b,c,37) R2(c,d,e,a,b,38) R2(b,c,d,e,a,39) + + R3(a,b,c,d,e,40) R3(e,a,b,c,d,41) R3(d,e,a,b,c,42) R3(c,d,e,a,b,43) + R3(b,c,d,e,a,44) R3(a,b,c,d,e,45) R3(e,a,b,c,d,46) R3(d,e,a,b,c,47) + R3(c,d,e,a,b,48) R3(b,c,d,e,a,49) R3(a,b,c,d,e,50) R3(e,a,b,c,d,51) + R3(d,e,a,b,c,52) R3(c,d,e,a,b,53) R3(b,c,d,e,a,54) R3(a,b,c,d,e,55) + R3(e,a,b,c,d,56) R3(d,e,a,b,c,57) R3(c,d,e,a,b,58) R3(b,c,d,e,a,59) + + + R4(a,b,c,d,e,60) R4(e,a,b,c,d,61) R4(d,e,a,b,c,62) R4(c,d,e,a,b,63) + R4(b,c,d,e,a,64) R4(a,b,c,d,e,65) R4(e,a,b,c,d,66) R4(d,e,a,b,c,67) + R4(c,d,e,a,b,68) R4(b,c,d,e,a,69) R4(a,b,c,d,e,70) R4(e,a,b,c,d,71) + R4(d,e,a,b,c,72) R4(c,d,e,a,b,73) R4(b,c,d,e,a,74) R4(a,b,c,d,e,75) + R4(e,a,b,c,d,76) R4(d,e,a,b,c,77) R4(c,d,e,a,b,78) R4(b,c,d,e,a,79) + + *h02 += a; + *h12 += b; + *h22 += c; + *h32 += d; + *h42 += e; +} +