Botan 2.19.3
Crypto and TLS for C&
chacha_rng.cpp
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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
10namespace 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
55void 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
61void 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
72void 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}
size_t security_level() const override
static std::unique_ptr< MessageAuthenticationCode > create_or_throw(const std::string &algo_spec, const std::string &provider="")
Definition mac.cpp:139
void clear() override final
void add_entropy(const uint8_t input[], size_t input_len) override final
static std::unique_ptr< StreamCipher > create_or_throw(const std::string &algo_spec, const std::string &provider="")
int(* update)(CTX *, const void *, CC_LONG len)
std::vector< T, secure_allocator< T > > secure_vector
Definition secmem.h:65