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Xtea.ino
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Xtea.ino
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/*
Xtea.cpp - Xtea encryption/decryption
Written by Frank Kienast in November, 2010
*/
#if defined(ARDUINO) && ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
#include "Xtea.h"
#define NUM_ROUNDS 32
Xtea::Xtea(unsigned long key[4])
{
_key[0] = key[0];
_key[1] = key[1];
_key[2] = key[2];
_key[3] = key[3];
}
void Xtea::encrypt(unsigned long v[2])
{
unsigned int i;
unsigned long v0=v[0], v1=v[1], sum=0, delta=0x9E3779B9;
for (i=0; i < NUM_ROUNDS; i++)
{
v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + _key[sum & 3]);
sum += delta;
v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + _key[(sum>>11) & 3]);
}
v[0]=v0; v[1]=v1;
}
void Xtea::encrypt(char pw[16])
{
}
void Xtea::decrypt(unsigned long v[2])
{
unsigned int i;
uint32_t v0=v[0], v1=v[1], delta=0x9E3779B9, sum=delta*NUM_ROUNDS;
for (i=0; i < NUM_ROUNDS; i++)
{
v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + _key[(sum>>11) & 3]);
sum -= delta;
v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + _key[sum & 3]);
}
v[0]=v0; v[1]=v1;
}
void Xtea::decrypt(char pw[16])
{
}