Botan  2.13.0
Crypto and TLS for C++11
gcm.h
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1 /*
2 * GCM Mode
3 * (C) 2013 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_GCM_H_
10 #define BOTAN_AEAD_GCM_H_
11 
12 #include <botan/aead.h>
13 #include <botan/sym_algo.h>
14 
16 
17 namespace Botan {
18 
19 class BlockCipher;
20 class StreamCipher;
21 class GHASH;
22 
23 /**
24 * GCM Mode
25 */
26 class BOTAN_PUBLIC_API(2,0) GCM_Mode : public AEAD_Mode
27  {
28  public:
29  void set_associated_data(const uint8_t ad[], size_t ad_len) override;
30 
31  std::string name() const override;
32 
33  size_t update_granularity() const override;
34 
35  Key_Length_Specification key_spec() const override;
36 
37  bool valid_nonce_length(size_t len) const override;
38 
39  size_t tag_size() const override { return m_tag_size; }
40 
41  void clear() override;
42 
43  void reset() override;
44 
45  std::string provider() const override;
46  protected:
47  GCM_Mode(BlockCipher* cipher, size_t tag_size);
48 
49  ~GCM_Mode();
50 
51  static const size_t GCM_BS = 16;
52 
53  const size_t m_tag_size;
54  const std::string m_cipher_name;
55 
56  std::unique_ptr<StreamCipher> m_ctr;
57  std::unique_ptr<GHASH> m_ghash;
58  private:
59  void start_msg(const uint8_t nonce[], size_t nonce_len) override;
60 
61  void key_schedule(const uint8_t key[], size_t length) override;
62 
64  };
65 
66 /**
67 * GCM Encryption
68 */
70  {
71  public:
72  /**
73  * @param cipher the 128 bit block cipher to use
74  * @param tag_size is how big the auth tag will be
75  */
76  GCM_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
77  GCM_Mode(cipher, tag_size) {}
78 
79  size_t output_length(size_t input_length) const override
80  { return input_length + tag_size(); }
81 
82  size_t minimum_final_size() const override { return 0; }
83 
84  size_t process(uint8_t buf[], size_t size) override;
85 
86  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
87  };
88 
89 /**
90 * GCM Decryption
91 */
93  {
94  public:
95  /**
96  * @param cipher the 128 bit block cipher to use
97  * @param tag_size is how big the auth tag will be
98  */
99  GCM_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
100  GCM_Mode(cipher, tag_size) {}
101 
102  size_t output_length(size_t input_length) const override
103  {
104  BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
105  return input_length - tag_size();
106  }
107 
108  size_t minimum_final_size() const override { return tag_size(); }
109 
110  size_t process(uint8_t buf[], size_t size) override;
111 
112  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
113  };
114 
115 }
116 
117 #endif
std::unique_ptr< StreamCipher > m_ctr
Definition: gcm.h:56
int(* final)(unsigned char *, CTX *)
virtual size_t update_granularity() const =0
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:31
GCM_Decryption(BlockCipher *cipher, size_t tag_size=16)
Definition: gcm.h:99
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0
virtual void reset()=0
const size_t m_tag_size
Definition: gcm.h:53
size_t minimum_final_size() const override
Definition: gcm.h:82
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:55
virtual std::string name() const =0
size_t output_length(size_t input_length) const override
Definition: gcm.h:79
virtual void clear()=0
GCM_Encryption(BlockCipher *cipher, size_t tag_size=16)
Definition: gcm.h:76
const std::string m_cipher_name
Definition: gcm.h:54
Definition: alg_id.cpp:13
size_t tag_size() const override
Definition: gcm.h:39
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:57
virtual Key_Length_Specification key_spec() const =0
virtual size_t process(uint8_t msg[], size_t msg_len)=0
size_t minimum_final_size() const override
Definition: gcm.h:108
size_t output_length(size_t input_length) const override
Definition: gcm.h:102
virtual std::string provider() const
Definition: cipher_mode.h:180
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65
virtual void set_associated_data(const uint8_t ad[], size_t ad_len)=0
#define BOTAN_FUTURE_INTERNAL_HEADER(hdr)
Definition: compiler.h:139
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