Botan  2.19.1
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 BOTAN_FUTURE_INTERNAL_HEADER(chacha20poly1305.h)
17 
18 namespace Botan {
19 
20 /**
21 * Base class
22 * See draft-irtf-cfrg-chacha20-poly1305-03 for specification
23 * If a nonce of 64 bits is used the older version described in
24 * draft-agl-tls-chacha20poly1305-04 is used instead.
25 * If a nonce of 192 bits is used, XChaCha20Poly1305 is selected.
26 */
28  {
29  public:
30  void set_associated_data(const uint8_t ad[], size_t ad_len) override;
31 
32  bool associated_data_requires_key() const override { return false; }
33 
34  std::string name() const override { return "ChaCha20Poly1305"; }
35 
36  size_t update_granularity() const override { return 64; }
37 
39  { return Key_Length_Specification(32); }
40 
41  bool valid_nonce_length(size_t n) const override;
42 
43  size_t tag_size() const override { return 16; }
44 
45  void clear() override;
46 
47  void reset() override;
48 
49  protected:
50  std::unique_ptr<StreamCipher> m_chacha;
51  std::unique_ptr<MessageAuthenticationCode> m_poly1305;
52 
54 
56  size_t m_nonce_len = 0;
57  size_t m_ctext_len = 0;
58 
59  bool cfrg_version() const { return m_nonce_len == 12 || m_nonce_len == 24; }
60  void update_len(size_t len);
61  private:
62  void start_msg(const uint8_t nonce[], size_t nonce_len) override;
63 
64  void key_schedule(const uint8_t key[], size_t length) override;
65  };
66 
67 /**
68 * ChaCha20Poly1305 Encryption
69 */
71  {
72  public:
73  size_t output_length(size_t input_length) const override
74  { return input_length + tag_size(); }
75 
76  size_t minimum_final_size() const override { return 0; }
77 
78  size_t process(uint8_t buf[], size_t size) override;
79 
80  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
81  };
82 
83 /**
84 * ChaCha20Poly1305 Decryption
85 */
87  {
88  public:
89  size_t output_length(size_t input_length) const override
90  {
91  BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
92  return input_length - tag_size();
93  }
94 
95  size_t minimum_final_size() const override { return tag_size(); }
96 
97  size_t process(uint8_t buf[], size_t size) override;
98 
99  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
100  };
101 
102 }
103 
104 #endif
std::unique_ptr< MessageAuthenticationCode > m_poly1305
int(* final)(unsigned char *, CTX *)
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:31
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0
std::unique_ptr< StreamCipher > m_chacha
virtual void reset()=0
bool associated_data_requires_key() const override
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:55
size_t minimum_final_size() const override
std::vector< T, secure_allocator< T >> secure_vector
Definition: secmem.h:65
size_t minimum_final_size() const override
size_t tag_size() const override
secure_vector< uint8_t > m_ad
virtual void clear()=0
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
virtual size_t process(uint8_t msg[], size_t msg_len)=0
Key_Length_Specification key_spec() const override
std::string name() const override
virtual void set_associated_data(const uint8_t ad[], size_t ad_len)=0
size_t update_granularity() const override
#define BOTAN_FUTURE_INTERNAL_HEADER(hdr)
Definition: compiler.h:136
virtual bool valid_nonce_length(size_t nonce_len) const =0
virtual void finish(secure_vector< uint8_t > &final_block, size_t offset=0)=0