mirror of
https://github.com/DarkStore-3DS/Project_CTR.git
synced 2026-07-04 08:49:03 +00:00
jakcron
69 lines
1.6 KiB
C++
69 lines
1.6 KiB
C++
/**
|
|
* @file BlockUtilImpl.h
|
|
* @brief Declaration of block utility functions for tc::crypto
|
|
* @author Jack (jakcron)
|
|
* @version 0.1
|
|
* @date 2020/10/04
|
|
**/
|
|
#pragma once
|
|
#include <tc/types.h>
|
|
|
|
namespace tc { namespace crypto { namespace detail {
|
|
|
|
template <size_t BlockSize>
|
|
inline void incr_counter(byte_t* counter, uint64_t incr)
|
|
{
|
|
for(uint64_t i = 0; i < incr; i++) {
|
|
for (uint32_t j = BlockSize; j > 0; j--) {
|
|
// increment u8 by 1
|
|
counter[j-1]++;
|
|
|
|
// if it didn't overflow to 0, then we can exit now
|
|
if (counter[j-1])
|
|
break;
|
|
|
|
// if we reach here, the next u8 needs to be incremented
|
|
if (j == 1)
|
|
j = BlockSize;
|
|
}
|
|
}
|
|
}
|
|
|
|
template <>
|
|
inline void incr_counter<16>(byte_t* counter, uint64_t incr)
|
|
{
|
|
tc::bn::be64<uint64_t>* counter_words = (tc::bn::be64<uint64_t>*)counter;
|
|
|
|
uint64_t carry = incr;
|
|
for (size_t i = 0; carry != 0 ; i = ((i + 1) % 2))
|
|
{
|
|
uint64_t word = counter_words[1 - i].unwrap();
|
|
uint64_t remaining = std::numeric_limits<uint64_t>::max() - word;
|
|
|
|
if (remaining > carry)
|
|
{
|
|
counter_words[1 - i].wrap(word + carry);
|
|
carry = 0;
|
|
}
|
|
else
|
|
{
|
|
counter_words[1 - i].wrap(carry - remaining - 1);
|
|
carry = 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
template <size_t BlockSize>
|
|
inline void xor_block(byte_t* dst, const byte_t* src_a, const byte_t* src_b)
|
|
{
|
|
for (size_t i = 0; i < BlockSize; i++) { dst[i] = src_a[i] ^ src_b[i];}
|
|
}
|
|
|
|
template <>
|
|
inline void xor_block<16>(byte_t* dst, const byte_t* src_a, const byte_t* src_b)
|
|
{
|
|
((uint64_t*)dst)[0] = ((uint64_t*)src_a)[0] ^ ((uint64_t*)src_b)[0];
|
|
((uint64_t*)dst)[1] = ((uint64_t*)src_a)[1] ^ ((uint64_t*)src_b)[1];
|
|
}
|
|
|
|
}}} // namespace tc::crypto::detail
|