Botan  2.18.1
Crypto and TLS for C++11
chacha_rng.cpp
Go to the documentation of this file.
1 /*
2 * ChaCha_RNG
3 * (C) 2017 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/chacha_rng.h>
9 
10 namespace Botan {
11 
13  {
14  m_hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
15  m_chacha = StreamCipher::create_or_throw("ChaCha(20)");
16  clear();
17  }
18 
20  {
21  m_hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
22  m_chacha = StreamCipher::create_or_throw("ChaCha(20)");
23  clear();
24  add_entropy(seed.data(), seed.size());
25  }
26 
28  size_t reseed_interval) :
29  Stateful_RNG(underlying_rng, reseed_interval)
30  {
31  m_hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
32  m_chacha = StreamCipher::create_or_throw("ChaCha(20)");
33  clear();
34  }
35 
37  Entropy_Sources& entropy_sources,
38  size_t reseed_interval) :
39  Stateful_RNG(underlying_rng, entropy_sources, reseed_interval)
40  {
41  m_hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
42  m_chacha = StreamCipher::create_or_throw("ChaCha(20)");
43  clear();
44  }
45 
47  size_t reseed_interval) :
48  Stateful_RNG(entropy_sources, reseed_interval)
49  {
50  m_hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
51  m_chacha = StreamCipher::create_or_throw("ChaCha(20)");
52  clear();
53  }
54 
55 void ChaCha_RNG::clear_state()
56  {
57  m_hmac->set_key(std::vector<uint8_t>(m_hmac->output_length(), 0x00));
58  m_chacha->set_key(m_hmac->final());
59  }
60 
61 void ChaCha_RNG::generate_output(uint8_t output[], size_t output_len,
62  const uint8_t input[], size_t input_len)
63  {
64  if(input_len > 0)
65  {
66  update(input, input_len);
67  }
68 
69  m_chacha->write_keystream(output, output_len);
70  }
71 
72 void ChaCha_RNG::update(const uint8_t input[], size_t input_len)
73  {
74  m_hmac->update(input, input_len);
75  m_chacha->set_key(m_hmac->final());
76 
77  secure_vector<uint8_t> mac_key(m_hmac->output_length());
78  m_chacha->write_keystream(mac_key.data(), mac_key.size());
79  m_hmac->set_key(mac_key);
80  }
81 
83  {
84  return 256;
85  }
86 
87 }
static std::unique_ptr< StreamCipher > create_or_throw(const std::string &algo_spec, const std::string &provider="")
size_t security_level() const override
Definition: chacha_rng.cpp:82
void add_entropy(const uint8_t input[], size_t input_len) override final
void clear() override final
Definition: alg_id.cpp:13
static std::unique_ptr< MessageAuthenticationCode > create_or_throw(const std::string &algo_spec, const std::string &provider="")
Definition: mac.cpp:141
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65