MySensors/drivers/ATSHA204/sha256.cpp

#include <string.h>
#if defined(__AVR__)
#include <avr/pgmspace.h>
#define PRIPSTR "%S"
#elif defined(ESP8266)
#include <pgmspace.h>
#endif
#include "sha256.h"


const uint32_t sha256K[] PROGMEM = {
	0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,
	0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,
	0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,
	0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,
	0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,
	0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,
	0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,
	0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2
};

const uint8_t sha256InitState[] PROGMEM = {
	0x67,0xe6,0x09,0x6a, // H0
	0x85,0xae,0x67,0xbb, // H1
	0x72,0xf3,0x6e,0x3c, // H2
	0x3a,0xf5,0x4f,0xa5, // H3
	0x7f,0x52,0x0e,0x51, // H4
	0x8c,0x68,0x05,0x9b, // H5
	0xab,0xd9,0x83,0x1f, // H6
	0x19,0xcd,0xe0,0x5b  // H7
};

// Suppress warning about uninitialized variables because initializing them in an init function
// allows the compiler to optimize away the variables in case the class is only instantiated but
// never used.
// cppcheck-suppress uninitMemberVar
Sha256Class::Sha256Class()
{
	/*
	memset(keyBuffer, 0, BLOCK_LENGTH);
	memset(innerHash, 0, HASH_LENGTH);
	memset(buffer.b, 0, BLOCK_LENGTH);
	memset(state.b, 0, BLOCK_LENGTH);
	bufferOffset = 0;
	byteCount = 0;
	*/
}


void Sha256Class::init(void)
{
	memcpy_P(state.b,sha256InitState,32);
	byteCount = 0;
	bufferOffset = 0;
}

uint32_t Sha256Class::ror32(uint32_t number, uint8_t bits)
{
	return ((number << (32-bits)) | (number >> bits));
}

void Sha256Class::hashBlock()
{
	uint8_t i;
	uint32_t a,b,c,d,e,f,g,h,t1,t2;

	a=state.w[0];
	b=state.w[1];
	c=state.w[2];
	d=state.w[3];
	e=state.w[4];
	f=state.w[5];
	g=state.w[6];
	h=state.w[7];

	for (i=0; i<64; i++) {
		if (i>=16) {
			t1 = buffer.w[i&15] + buffer.w[(i-7)&15];
			t2 = buffer.w[(i-2)&15];
			t1 += ror32(t2,17) ^ ror32(t2,19) ^ (t2>>10);
			t2 = buffer.w[(i-15)&15];
			t1 += ror32(t2,7) ^ ror32(t2,18) ^ (t2>>3);
			buffer.w[i&15] = t1;
		}
		t1 = h;
		t1 += ror32(e,6) ^ ror32(e,11) ^ ror32(e,25); // ∑1(e)
		t1 += g ^ (e & (g ^ f)); // Ch(e,f,g)
		t1 += pgm_read_dword(sha256K+i); // Ki
		t1 += buffer.w[i&15]; // Wi
		t2 = ror32(a,2) ^ ror32(a,13) ^ ror32(a,22); // ∑0(a)
		t2 += ((b & c) | (a & (b | c))); // Maj(a,b,c)
		h=g;
		g=f;
		f=e;
		e=d+t1;
		d=c;
		c=b;
		b=a;
		a=t1+t2;
	}
	state.w[0] += a;
	state.w[1] += b;
	state.w[2] += c;
	state.w[3] += d;
	state.w[4] += e;
	state.w[5] += f;
	state.w[6] += g;
	state.w[7] += h;
}

void Sha256Class::addUncounted(uint8_t data)
{
	buffer.b[bufferOffset ^ 3] = data;
	bufferOffset++;
	if (bufferOffset == BLOCK_LENGTH) {
		hashBlock();
		bufferOffset = 0;
	}
}

void Sha256Class::write(uint8_t data)
{
	++byteCount;
	addUncounted(data);
}

void Sha256Class::pad()
{
	// Implement SHA-256 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* Sha256Class::result(void)
{
	// Pad to complete the last block
	pad();

	// Swap byte order back
	for (int i=0; i<8; 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

// Suppress warning about uninitialized variables because initializing them in an init function
// allows the compiler to optimize away the variables in case the class is only instantiated but
// never used.
// cppcheck-suppress uninitMemberVar
HmacClass::HmacClass()
{
}

void HmacClass::initHmac(const uint8_t* key, int 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* HmacClass::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();
}