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/*
* SHAKE-128/256 as a hash
* (C) 2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/shake.h>
#include <botan/sha3.h>
#include <botan/parsing.h>
#include <botan/exceptn.h>
namespace Botan {
SHAKE_128::SHAKE_128(size_t output_bits) :
m_output_bits(output_bits), m_S(25), m_S_pos(0)
{
if(output_bits % 8 != 0)
throw Invalid_Argument("SHAKE_128: Invalid output length " +
std::to_string(output_bits));
}
std::string SHAKE_128::name() const
{
return "SHAKE-128(" + std::to_string(m_output_bits) + ")";
}
HashFunction* SHAKE_128::clone() const
{
return new SHAKE_128(m_output_bits);
}
std::unique_ptr<HashFunction> SHAKE_128::copy_state() const
{
return std::unique_ptr<HashFunction>(new SHAKE_128(*this));
}
void SHAKE_128::clear()
{
zeroise(m_S);
m_S_pos = 0;
}
void SHAKE_128::add_data(const uint8_t input[], size_t length)
{
m_S_pos = SHA_3::absorb(SHAKE_128_BITRATE, m_S, m_S_pos, input, length);
}
void SHAKE_128::final_result(uint8_t output[])
{
std::vector<uint8_t> padding(SHAKE_128_BITRATE / 8 - m_S_pos);
padding[0] = 0x1F;
padding[padding.size()-1] |= 0x80;
add_data(padding.data(), padding.size());
SHA_3::expand(SHAKE_128_BITRATE, m_S, output, output_length());
clear();
}
SHAKE_256::SHAKE_256(size_t output_bits) :
m_output_bits(output_bits), m_S(25), m_S_pos(0)
{
if(output_bits % 8 != 0)
throw Invalid_Argument("SHAKE_256: Invalid output length " +
std::to_string(output_bits));
}
std::string SHAKE_256::name() const
{
return "SHAKE-256(" + std::to_string(m_output_bits) + ")";
}
HashFunction* SHAKE_256::clone() const
{
return new SHAKE_256(m_output_bits);
}
std::unique_ptr<HashFunction> SHAKE_256::copy_state() const
{
return std::unique_ptr<HashFunction>(new SHAKE_256(*this));
}
void SHAKE_256::clear()
{
zeroise(m_S);
m_S_pos = 0;
}
void SHAKE_256::add_data(const uint8_t input[], size_t length)
{
m_S_pos = SHA_3::absorb(SHAKE_256_BITRATE, m_S, m_S_pos, input, length);
}
void SHAKE_256::final_result(uint8_t output[])
{
std::vector<uint8_t> padding(SHAKE_256_BITRATE / 8 - m_S_pos);
padding[0] = 0x1F;
padding[padding.size()-1] |= 0x80;
add_data(padding.data(), padding.size());
SHA_3::expand(SHAKE_256_BITRATE, m_S, output, output_length());
clear();
}
}
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