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/*
* (C) 2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/mem_ops.h>
namespace Botan {
bool constant_time_compare(const uint8_t x[],
const uint8_t y[],
size_t len)
{
volatile uint8_t difference = 0;
for(size_t i = 0; i != len; ++i)
difference |= (x[i] ^ y[i]);
return difference == 0;
}
void xor_buf(uint8_t x[],
const uint8_t y[],
size_t len)
{
while(len >= 16)
{
x[0] ^= y[0];
x[1] ^= y[1];
x[2] ^= y[2];
x[3] ^= y[3];
x[4] ^= y[4];
x[5] ^= y[5];
x[6] ^= y[6];
x[7] ^= y[7];
x[8] ^= y[8];
x[9] ^= y[9];
x[10] ^= y[10];
x[11] ^= y[11];
x[12] ^= y[12];
x[13] ^= y[13];
x[14] ^= y[14];
x[15] ^= y[15];
x += 16; y += 16; len -= 16;
}
for(size_t i = 0; i != len; ++i)
{
x[i] ^= y[i];
}
}
void xor_buf(uint8_t out[],
const uint8_t in[],
const uint8_t in2[],
size_t length)
{
while(length >= 16)
{
out[0] = in[0] ^ in2[0];
out[1] = in[1] ^ in2[1];
out[2] = in[2] ^ in2[2];
out[3] = in[3] ^ in2[3];
out[4] = in[4] ^ in2[4];
out[5] = in[5] ^ in2[5];
out[6] = in[6] ^ in2[6];
out[7] = in[7] ^ in2[7];
out[8] = in[8] ^ in2[8];
out[9] = in[9] ^ in2[9];
out[10] = in[10] ^ in2[10];
out[11] = in[11] ^ in2[11];
out[12] = in[12] ^ in2[12];
out[13] = in[13] ^ in2[13];
out[14] = in[14] ^ in2[14];
out[15] = in[15] ^ in2[15];
in += 16; in2 += 16; out += 16; length -= 16;
}
for(size_t i = 0; i != length; ++i)
out[i] = in[i] ^ in2[i];
}
}
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