Botan  2.7.0
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 */
25  {
26  public:
27  void set_associated_data(const uint8_t ad[], size_t ad_len) override;
28 
29  std::string name() const override { return "ChaCha20Poly1305"; }
30 
31  size_t update_granularity() const override { return 64; }
32 
34  { return Key_Length_Specification(32); }
35 
36  bool valid_nonce_length(size_t n) const override;
37 
38  size_t tag_size() const override { return 16; }
39 
40  void clear() override;
41 
42  void reset() override;
43 
44  protected:
45  std::unique_ptr<StreamCipher> m_chacha;
46  std::unique_ptr<MessageAuthenticationCode> m_poly1305;
47 
49 
51  size_t m_nonce_len = 0;
52  size_t m_ctext_len = 0;
53 
54  bool cfrg_version() const { return m_nonce_len == 12; }
55  void update_len(size_t len);
56  private:
57  void start_msg(const uint8_t nonce[], size_t nonce_len) override;
58 
59  void key_schedule(const uint8_t key[], size_t length) override;
60  };
61 
62 /**
63 * ChaCha20Poly1305 Encryption
64 */
66  {
67  public:
68  size_t output_length(size_t input_length) const override
69  { return input_length + tag_size(); }
70 
71  size_t minimum_final_size() const override { return 0; }
72 
73  size_t process(uint8_t buf[], size_t size) override;
74 
75  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
76  };
77 
78 /**
79 * ChaCha20Poly1305 Decryption
80 */
82  {
83  public:
84  size_t output_length(size_t input_length) const override
85  {
86  BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
87  return input_length - tag_size();
88  }
89 
90  size_t minimum_final_size() const override { return tag_size(); }
91 
92  size_t process(uint8_t buf[], size_t size) override;
93 
94  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
95  };
96 
97 }
98 
99 #endif
std::unique_ptr< MessageAuthenticationCode > m_poly1305
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:27
std::unique_ptr< StreamCipher > m_chacha
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:43
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