Botan 3.0.0
Crypto and TLS for C&
chacha.h
Go to the documentation of this file.
1/*
2* ChaCha20
3* (C) 2014,2018 Jack Lloyd
4*
5* Botan is released under the Simplified BSD License (see license.txt)
6*/
7
8#ifndef BOTAN_CHACHA_H_
9#define BOTAN_CHACHA_H_
10
11#include <botan/stream_cipher.h>
12
13namespace Botan {
14
15/**
16* DJB's ChaCha (https://cr.yp.to/chacha.html)
17*/
19 {
20 public:
21 /**
22 * @param rounds number of rounds
23 * @note Currently only 8, 12 or 20 rounds are supported, all others
24 * will throw an exception
25 */
26 explicit ChaCha(size_t rounds = 20);
27
28 std::string provider() const override;
29
30 /*
31 * ChaCha accepts 0, 8, 12 or 24 byte IVs.
32 * The default IV is a 8 zero bytes.
33 * An IV of length 0 is treated the same as the default zero IV.
34 * An IV of length 24 selects XChaCha mode
35 */
36 bool valid_iv_length(size_t iv_len) const override;
37
38 size_t default_iv_length() const override;
39
40 Key_Length_Specification key_spec() const override;
41
42 void clear() override;
43
44 std::unique_ptr<StreamCipher> new_object() const override;
45
46 std::string name() const override;
47
48 void seek(uint64_t offset) override;
49
50 bool has_keying_material() const override;
51
52 size_t buffer_size() const override;
53 private:
54 void key_schedule(const uint8_t key[], size_t key_len) override;
55
56 void cipher_bytes(const uint8_t in[], uint8_t out[], size_t length) override;
57
58 void generate_keystream(uint8_t out[], size_t len) override;
59
60 void set_iv_bytes(const uint8_t iv[], size_t iv_len) override;
61
62 void initialize_state();
63
64 static size_t parallelism();
65
66 static void chacha(uint8_t output[],
67 size_t output_blocks,
68 uint32_t state[16],
69 size_t rounds);
70
71#if defined(BOTAN_HAS_CHACHA_SIMD32)
72 static void chacha_simd32_x4(uint8_t output[64*4], uint32_t state[16], size_t rounds);
73#endif
74
75#if defined(BOTAN_HAS_CHACHA_AVX2)
76 static void chacha_avx2_x8(uint8_t output[64*8], uint32_t state[16], size_t rounds);
77#endif
78
79 size_t m_rounds;
83 size_t m_position = 0;
84 };
85
86}
87
88#endif
void clear() override
Definition: chacha.cpp:389
std::string name() const override
Definition: chacha.cpp:397
size_t buffer_size() const override
Definition: chacha.cpp:293
std::unique_ptr< StreamCipher > new_object() const override
Definition: chacha.cpp:324
Key_Length_Specification key_spec() const override
Definition: chacha.cpp:319
bool valid_iv_length(size_t iv_len) const override
Definition: chacha.cpp:329
size_t default_iv_length() const override
Definition: chacha.cpp:314
std::string provider() const override
Definition: chacha.cpp:83
bool has_keying_material() const override
Definition: chacha.cpp:288
void seek(uint64_t offset) override
Definition: chacha.cpp:402
int(* final)(unsigned char *, CTX *)
Definition: alg_id.cpp:12
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:64