Botan 2.13.0 Crypto and TLS for C++11

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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
10 namespace Botan {
11
12 ChaCha_RNG::ChaCha_RNG() : Stateful_RNG()
13 {
14 m_hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
15 m_chacha = StreamCipher::create_or_throw("ChaCha(20)");
16 clear();
17 }
18
19 ChaCha_RNG::ChaCha_RNG(const secure_vector<uint8_t>& seed) : Stateful_RNG()
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
27 ChaCha_RNG::ChaCha_RNG(RandomNumberGenerator& underlying_rng,
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
36 ChaCha_RNG::ChaCha_RNG(RandomNumberGenerator& underlying_rng,
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
46 ChaCha_RNG::ChaCha_RNG(Entropy_Sources& entropy_sources,
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()
56 {
57 Stateful_RNG::clear();
58
59 m_hmac->set_key(std::vector<uint8_t>(m_hmac->output_length(), 0x00));
60 m_chacha->set_key(m_hmac->final());
61 }
62
63 void ChaCha_RNG::randomize(uint8_t output[], size_t output_len)
64 {
65 randomize_with_input(output, output_len, nullptr, 0);
66 }
67
68 void ChaCha_RNG::randomize_with_input(uint8_t output[], size_t output_len,
69 const uint8_t input[], size_t input_len)
70 {
71 reseed_check();
72
73 if(input_len > 0)
74 {
75 update(input, input_len);
76 }
77
78 m_chacha->write_keystream(output, output_len);
79 }
80
81 void ChaCha_RNG::update(const uint8_t input[], size_t input_len)
82 {
83 m_hmac->update(input, input_len);
84 m_chacha->set_key(m_hmac->final());
85
86 secure_vector<uint8_t> mac_key(m_hmac->output_length());
87 m_chacha->write_keystream(mac_key.data(), mac_key.size());
88 m_hmac->set_key(mac_key);
89 }
90
91 void ChaCha_RNG::add_entropy(const uint8_t input[], size_t input_len)
92 {
93 update(input, input_len);
94
95 if(8*input_len >= security_level())
96 {
97 reset_reseed_counter();
98 }
99 }
100
101 size_t ChaCha_RNG::security_level() const
102 {
103 return 256;
104 }
105
106 }
Botan::Stateful_RNG
Definition: stateful_rng.h:25
Botan::ChaCha_RNG::add_entropy
void add_entropy(const uint8_t input[], size_t input_len) override
Definition: chacha_rng.cpp:91
Botan::ChaCha_RNG::ChaCha_RNG
ChaCha_RNG()
Definition: chacha_rng.cpp:12
Botan::StreamCipher::create_or_throw
static std::unique_ptr< StreamCipher > create_or_throw(const std::string &algo_spec, const std::string &provider="")
Definition: stream_cipher.cpp:134
Botan::RandomNumberGenerator
Definition: rng.h:24
Botan::ChaCha_RNG::security_level
size_t security_level() const override
Definition: chacha_rng.cpp:101
Botan::Stateful_RNG::clear
void clear() override
Definition: stateful_rng.cpp:17
Botan::ChaCha_RNG::clear
void clear() override
Definition: chacha_rng.cpp:55
Botan::secure_vector
std::vector< T, secure_allocator< T >> secure_vector
Definition: secmem.h:65
Botan
Definition: alg_id.cpp:13
Botan::Stateful_RNG::reseed_check
void reseed_check()
Definition: stateful_rng.cpp:90
Botan::ChaCha_RNG::randomize
void randomize(uint8_t output[], size_t output_len) override
Definition: chacha_rng.cpp:63
Botan::Stateful_RNG::reset_reseed_counter
void reset_reseed_counter()
Definition: stateful_rng.h:131
Botan::Entropy_Sources
Definition: entropy_src.h:56
Botan::MessageAuthenticationCode::create_or_throw
static std::unique_ptr< MessageAuthenticationCode > create_or_throw(const std::string &algo_spec, const std::string &provider="")
Definition: mac.cpp:141
Botan::ChaCha_RNG::randomize_with_input
void randomize_with_input(uint8_t output[], size_t output_len, const uint8_t input[], size_t input_len) override
Definition: chacha_rng.cpp:68