Botan  2.19.1
Crypto and TLS for C++11
siv.h
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1 /*
2 * SIV 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_SIV_H_
10 #define BOTAN_AEAD_SIV_H_
11 
12 #include <botan/aead.h>
13 #include <botan/stream_cipher.h>
14 
16 
17 namespace Botan {
18 
19 class BlockCipher;
20 class MessageAuthenticationCode;
21 
22 /**
23 * Base class for SIV encryption and decryption (@see RFC 5297)
24 */
25 class BOTAN_PUBLIC_API(2,0) SIV_Mode : public AEAD_Mode
26  {
27  public:
28  size_t process(uint8_t buf[], size_t size) override;
29 
30  /**
31  * Sets the nth element of the vector of associated data
32  * @param n index into the AD vector
33  * @param ad associated data
34  * @param ad_len length of associated data in bytes
35  */
36  void set_associated_data_n(size_t n, const uint8_t ad[], size_t ad_len) override;
37 
38  size_t maximum_associated_data_inputs() const override;
39 
40  void set_associated_data(const uint8_t ad[], size_t ad_len) override
41  {
42  set_associated_data_n(0, ad, ad_len);
43  }
44 
45  std::string name() const override;
46 
47  size_t update_granularity() const override;
48 
49  Key_Length_Specification key_spec() const override;
50 
51  bool valid_nonce_length(size_t) const override;
52 
53  void clear() override;
54 
55  void reset() override;
56 
57  size_t tag_size() const override { return 16; }
58 
59  ~SIV_Mode();
60 
61  protected:
62  explicit SIV_Mode(BlockCipher* cipher);
63 
64  size_t block_size() const { return m_bs; }
65 
66  StreamCipher& ctr() { return *m_ctr; }
67 
68  void set_ctr_iv(secure_vector<uint8_t> V);
69 
70  secure_vector<uint8_t>& msg_buf() { return m_msg_buf; }
71 
72  secure_vector<uint8_t> S2V(const uint8_t text[], size_t text_len);
73  private:
74  void start_msg(const uint8_t nonce[], size_t nonce_len) override;
75 
76  void key_schedule(const uint8_t key[], size_t length) override;
77 
78  const std::string m_name;
79  std::unique_ptr<StreamCipher> m_ctr;
80  std::unique_ptr<MessageAuthenticationCode> m_mac;
81  secure_vector<uint8_t> m_nonce, m_msg_buf;
82  std::vector<secure_vector<uint8_t>> m_ad_macs;
83  const size_t m_bs;
84  };
85 
86 /**
87 * SIV Encryption
88 */
90  {
91  public:
92  /**
93  * @param cipher a block cipher
94  */
95  explicit SIV_Encryption(BlockCipher* cipher) : SIV_Mode(cipher) {}
96 
97  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
98 
99  size_t output_length(size_t input_length) const override
100  { return input_length + tag_size(); }
101 
102  size_t minimum_final_size() const override { return 0; }
103  };
104 
105 /**
106 * SIV Decryption
107 */
109  {
110  public:
111  /**
112  * @param cipher a 128-bit block cipher
113  */
114  explicit SIV_Decryption(BlockCipher* cipher) : SIV_Mode(cipher) {}
115 
116  void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
117 
118  size_t output_length(size_t input_length) const override
119  {
120  BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
121  return input_length - tag_size();
122  }
123 
124  size_t minimum_final_size() const override { return tag_size(); }
125  };
126 
127 }
128 
129 #endif
secure_vector< uint8_t > & msg_buf()
Definition: siv.h:70
size_t output_length(size_t input_length) const override
Definition: siv.h:118
virtual size_t maximum_associated_data_inputs() const
Definition: aead.h:87
std::string m_name
int(* final)(unsigned char *, CTX *)
virtual size_t update_granularity() const =0
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:31
SIV_Encryption(BlockCipher *cipher)
Definition: siv.h:95
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0
size_t block_size() const
Definition: siv.h:64
virtual void reset()=0
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:55
std::vector< T, secure_allocator< T >> secure_vector
Definition: secmem.h:65
size_t minimum_final_size() const override
Definition: siv.h:124
SIV_Decryption(BlockCipher *cipher)
Definition: siv.h:114
virtual std::string name() const =0
void set_associated_data(const uint8_t ad[], size_t ad_len) override
Definition: siv.h:40
virtual void clear()=0
Definition: alg_id.cpp:13
size_t tag_size() const override
Definition: siv.h:57
virtual Key_Length_Specification key_spec() const =0
virtual size_t process(uint8_t msg[], size_t msg_len)=0
StreamCipher & ctr()
Definition: siv.h:66
virtual void set_associated_data_n(size_t i, const uint8_t ad[], size_t ad_len)
Definition: aead.cpp:42
size_t output_length(size_t input_length) const override
Definition: siv.h:99
#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
size_t minimum_final_size() const override
Definition: siv.h:102