Botan  2.1.0
Crypto and TLS for C++11
keccak.cpp
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1 /*
2 * Keccak
3 * (C) 2010,2016 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/keccak.h>
9 #include <botan/sha3.h>
10 #include <botan/parsing.h>
11 #include <botan/exceptn.h>
12 
13 namespace Botan {
14 
15 Keccak_1600::Keccak_1600(size_t output_bits) :
16  m_output_bits(output_bits),
17  m_bitrate(1600 - 2*output_bits),
18  m_S(25),
19  m_S_pos(0)
20  {
21  // We only support the parameters for the SHA-3 proposal
22 
23  if(output_bits != 224 && output_bits != 256 &&
24  output_bits != 384 && output_bits != 512)
25  throw Invalid_Argument("Keccak_1600: Invalid output length " +
26  std::to_string(output_bits));
27  }
28 
29 std::string Keccak_1600::name() const
30  {
31  return "Keccak-1600(" + std::to_string(m_output_bits) + ")";
32  }
33 
35  {
36  return new Keccak_1600(m_output_bits);
37  }
38 
40  {
41  zeroise(m_S);
42  m_S_pos = 0;
43  }
44 
45 void Keccak_1600::add_data(const uint8_t input[], size_t length)
46  {
47  m_S_pos = SHA_3::absorb(m_bitrate, m_S, m_S_pos, input, length);
48  }
49 
50 void Keccak_1600::final_result(uint8_t output[])
51  {
52  std::vector<uint8_t> padding(m_bitrate / 8 - m_S_pos);
53 
54  padding[0] = 0x01;
55  padding[padding.size()-1] |= 0x80;
56 
57  add_data(padding.data(), padding.size());
58 
59  /*
60  * We never have to run the permutation again because we only support
61  * limited output lengths
62  */
63  for(size_t i = 0; i != m_output_bits/8; ++i)
64  output[i] = get_byte(7 - (i % 8), m_S[i/8]);
65 
66  clear();
67  }
68 
69 }
std::string to_string(const BER_Object &obj)
Definition: asn1_obj.cpp:47
static size_t absorb(size_t bitrate, secure_vector< uint64_t > &S, size_t S_pos, const uint8_t input[], size_t length)
Definition: sha3.cpp:129
HashFunction * clone() const override
Definition: keccak.cpp:34
std::string name() const override
Definition: keccak.cpp:29
Definition: alg_id.cpp:13
uint8_t get_byte(size_t byte_num, T input)
Definition: loadstor.h:47
Keccak_1600(size_t output_bits=512)
Definition: keccak.cpp:15
void clear() override
Definition: keccak.cpp:39
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:211