Botan  2.8.0
Crypto and TLS for C++11
chacha20poly1305.h
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1 /*
2 * ChaCha20Poly1305 AEAD
3 * (C) 2014 Jack Lloyd
4 * (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
5 *
6 * Botan is released under the Simplified BSD License (see license.txt)
7 */
8 
9 #ifndef BOTAN_AEAD_CHACHA20_POLY1305_H_
10 #define BOTAN_AEAD_CHACHA20_POLY1305_H_
11 
12 #include <botan/aead.h>
13 #include <botan/stream_cipher.h>
14 #include <botan/mac.h>
15 
16 namespace Botan {
17 
18 /**
19 * Base class
20 * See draft-irtf-cfrg-chacha20-poly1305-03 for specification
21 * If a nonce of 64 bits is used the older version described in
22 * draft-agl-tls-chacha20poly1305-04 is used instead.
23 * If a nonce of 192 bits is used, XChaCha20Poly1305 is selected.
24 */
26  {
27  public:
28  void set_associated_data(const uint8_t ad[], size_t ad_len) override;
29 
30  bool associated_data_requires_key() const override { return false; }
31 
32  std::string name() const override { return "ChaCha20Poly1305"; }
33 
34  size_t update_granularity() const override { return 64; }
35 
37  { return Key_Length_Specification(32); }
38 
39  bool valid_nonce_length(size_t n) const override;
40 
41  size_t tag_size() const override { return 16; }
42 
43  void clear() override;
44 
45  void reset() override;
46 
47  protected:
48  std::unique_ptr<StreamCipher> m_chacha;
49  std::unique_ptr<MessageAuthenticationCode> m_poly1305;
50 
52 
54  size_t m_nonce_len = 0;
55  size_t m_ctext_len = 0;
56 
57  bool cfrg_version() const { return m_nonce_len == 12 || m_nonce_len == 24; }
58  void update_len(size_t len);
59  private:
60  void start_msg(const uint8_t nonce[], size_t nonce_len) override;
61 
62  void key_schedule(const uint8_t key[], size_t length) override;
63  };
64 
65 /**
66 * ChaCha20Poly1305 Encryption
67 */
69  {
70  public:
71  size_t output_length(size_t input_length) const override
72  { return input_length + tag_size(); }
73 
74  size_t minimum_final_size() const override { return 0; }
75 
76  size_t process(uint8_t buf[], size_t size) override;
77 
78  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
79  };
80 
81 /**
82 * ChaCha20Poly1305 Decryption
83 */
85  {
86  public:
87  size_t output_length(size_t input_length) const override
88  {
89  BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
90  return input_length - tag_size();
91  }
92 
93  size_t minimum_final_size() const override { return tag_size(); }
94 
95  size_t process(uint8_t buf[], size_t size) override;
96 
97  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
98  };
99 
100 }
101 
102 #endif
std::unique_ptr< MessageAuthenticationCode > m_poly1305
int(* final)(unsigned char *, CTX *)
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:27
std::unique_ptr< StreamCipher > m_chacha
bool associated_data_requires_key() const override
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:55
size_t minimum_final_size() const override
size_t minimum_final_size() const override
size_t tag_size() const override
secure_vector< uint8_t > m_ad
Definition: alg_id.cpp:13
size_t output_length(size_t input_length) const override
size_t output_length(size_t input_length) const override
Key_Length_Specification key_spec() const override
std::string name() const override
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:88
size_t update_granularity() const override