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#include <string.h>
#include "sha1.h"
#define SHA1_K0 0x5a827999
#define SHA1_K20 0x6ed9eba1
#define SHA1_K40 0x8f1bbcdc
#define SHA1_K60 0xca62c1d6
uint8_t sha1InitState[] = {
0x01,0x23,0x45,0x67, // H0
0x89,0xab,0xcd,0xef, // H1
0xfe,0xdc,0xba,0x98, // H2
0x76,0x54,0x32,0x10, // H3
0xf0,0xe1,0xd2,0xc3 // H4
};
union _buffer {
uint8_t b[BLOCK_LENGTH];
uint32_t w[BLOCK_LENGTH/4];
} buffer;
union _state {
uint8_t b[HASH_LENGTH];
uint32_t w[HASH_LENGTH/4];
} state;
uint8_t bufferOffset;
uint32_t byteCount;
uint8_t keyBuffer[BLOCK_LENGTH];
uint8_t innerHash[HASH_LENGTH];
void init(void) {
memcpy(state.b,sha1InitState,HASH_LENGTH);
byteCount = 0;
bufferOffset = 0;
}
static uint32_t rol32(uint32_t number, uint8_t bits) {
return ((number << bits) | (uint32_t)(number >> (32-bits)));
}
static void hashBlock(void) {
uint8_t i;
uint32_t a,b,c,d,e,t;
a=state.w[0];
b=state.w[1];
c=state.w[2];
d=state.w[3];
e=state.w[4];
for (i=0; i<80; i++) {
if (i>=16) {
t = buffer.w[(i+13)&15] ^ buffer.w[(i+8)&15] ^ buffer.w[(i+2)&15] ^ buffer.w[i&15];
buffer.w[i&15] = rol32(t,1);
}
if (i<20) {
t = (d ^ (b & (c ^ d))) + SHA1_K0;
} else if (i<40) {
t = (b ^ c ^ d) + SHA1_K20;
} else if (i<60) {
t = ((b & c) | (d & (b | c))) + SHA1_K40;
} else {
t = (b ^ c ^ d) + SHA1_K60;
}
t+=rol32(a,5) + e + buffer.w[i&15];
e=d;
d=c;
c=rol32(b,30);
b=a;
a=t;
}
state.w[0] += a;
state.w[1] += b;
state.w[2] += c;
state.w[3] += d;
state.w[4] += e;
}
static void addUncounted(uint8_t data) {
buffer.b[bufferOffset ^ 3] = data;
bufferOffset++;
if (bufferOffset == BLOCK_LENGTH) {
hashBlock();
bufferOffset = 0;
}
}
static void __write(uint8_t data) {
++byteCount;
addUncounted(data);
return;
}
void writeArray(uint8_t *buffer, uint8_t size){
while (size--) {
__write(*buffer++);
}
}
static void pad(void) {
// Implement SHA-1 padding (fips180-2 ��5.1.1)
// Pad with 0x80 followed by 0x00 until the end of the block
addUncounted(0x80);
while (bufferOffset != 56) addUncounted(0x00);
// Append length in the last 8 bytes
addUncounted(0); // We're only using 32 bit lengths
addUncounted(0); // But SHA-1 supports 64 bit lengths
addUncounted(0); // So zero pad the top bits
addUncounted(byteCount >> 29); // Shifting to multiply by 8
addUncounted(byteCount >> 21); // as SHA-1 supports bitstreams as well as
addUncounted(byteCount >> 13); // byte.
addUncounted(byteCount >> 5);
addUncounted(byteCount << 3);
}
uint8_t* result(void) {
// Pad to complete the last block
pad();
// Swap byte order back
uint8_t i;
for (i=0; i<5; i++) {
uint32_t a,b;
a=state.w[i];
b=a<<24;
b|=(a<<8) & 0x00ff0000;
b|=(a>>8) & 0x0000ff00;
b|=a>>24;
state.w[i]=b;
}
// Return pointer to hash (20 characters)
return state.b;
}
#define HMAC_IPAD 0x36
#define HMAC_OPAD 0x5c
void initHmac(const uint8_t* key, uint8_t keyLength) {
uint8_t i;
memset(keyBuffer,0,BLOCK_LENGTH);
if (keyLength > BLOCK_LENGTH) {
// Hash long keys
init();
for (;keyLength--;) __write(*key++);
memcpy(keyBuffer,result(),HASH_LENGTH);
} else {
// Block length keys are used as is
memcpy(keyBuffer,key,keyLength);
}
// Start inner hash
init();
for (i=0; i<BLOCK_LENGTH; i++) {
__write(keyBuffer[i] ^ HMAC_IPAD);
}
}
uint8_t* resultHmac(void) {
uint8_t i;
// Complete inner hash
memcpy(innerHash,result(),HASH_LENGTH);
// Calculate outer hash
init();
for (i=0; i<BLOCK_LENGTH; i++) __write(keyBuffer[i] ^ HMAC_OPAD);
for (i=0; i<HASH_LENGTH; i++) __write(innerHash[i]);
return result();
}
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