/src/botan/build/include/botan/internal/ocb.h
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * OCB Mode |
3 | | * (C) 2013,2014 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_OCB_H_ |
10 | | #define BOTAN_AEAD_OCB_H_ |
11 | | |
12 | | #include <botan/aead.h> |
13 | | |
14 | | namespace Botan { |
15 | | |
16 | | class BlockCipher; |
17 | | class L_computer; |
18 | | |
19 | | /** |
20 | | * OCB Mode (base class for OCB_Encryption and OCB_Decryption). |
21 | | * OCB was previously patented in the United States but the patent |
22 | | * has now been allowed to lapse. |
23 | | * |
24 | | * @see "The OCB Authenticated-Encryption Algorithm" RFC 7253 |
25 | | * https://tools.ietf.org/html/rfc7253 |
26 | | * @see "OCB For Block Ciphers Without 128-Bit Blocks" |
27 | | * (draft-krovetz-ocb-wide-d3) for the extension of OCB to |
28 | | * block ciphers with larger block sizes. |
29 | | * @see https://mailarchive.ietf.org/arch/msg/cfrg/qLTveWOdTJcLn4HP3ev-vrj05Vg/ |
30 | | */ |
31 | | class BOTAN_TEST_API OCB_Mode : public AEAD_Mode |
32 | | { |
33 | | public: |
34 | | void set_associated_data(const uint8_t ad[], size_t ad_len) override; |
35 | | |
36 | | std::string name() const override; |
37 | | |
38 | | size_t update_granularity() const override; |
39 | | |
40 | | Key_Length_Specification key_spec() const override; |
41 | | |
42 | | bool valid_nonce_length(size_t) const override; |
43 | | |
44 | 974 | size_t tag_size() const override { return m_tag_size; } |
45 | | |
46 | | void clear() override; |
47 | | |
48 | | void reset() override; |
49 | | |
50 | | ~OCB_Mode(); |
51 | | protected: |
52 | | /** |
53 | | * @param cipher the block cipher to use |
54 | | * @param tag_size is how big the auth tag will be |
55 | | */ |
56 | | OCB_Mode(std::unique_ptr<BlockCipher> cipher, size_t tag_size); |
57 | | |
58 | 1.10k | size_t block_size() const { return m_block_size; } |
59 | 448 | size_t par_blocks() const { return m_par_blocks; } |
60 | 0 | size_t par_bytes() const { return m_checksum.size(); } |
61 | | |
62 | | // fixme make these private |
63 | | std::unique_ptr<BlockCipher> m_cipher; |
64 | | std::unique_ptr<L_computer> m_L; |
65 | | |
66 | | size_t m_block_index = 0; |
67 | | |
68 | | secure_vector<uint8_t> m_checksum; |
69 | | secure_vector<uint8_t> m_ad_hash; |
70 | | private: |
71 | | void start_msg(const uint8_t nonce[], size_t nonce_len) override; |
72 | | |
73 | | void key_schedule(const uint8_t key[], size_t length) override; |
74 | | |
75 | | const secure_vector<uint8_t>& update_nonce(const uint8_t nonce[], size_t nonce_len); |
76 | | |
77 | | const size_t m_tag_size; |
78 | | const size_t m_block_size; |
79 | | const size_t m_par_blocks; |
80 | | secure_vector<uint8_t> m_last_nonce; |
81 | | secure_vector<uint8_t> m_stretch; |
82 | | secure_vector<uint8_t> m_nonce_buf; |
83 | | secure_vector<uint8_t> m_offset; |
84 | | }; |
85 | | |
86 | | class BOTAN_TEST_API OCB_Encryption final : public OCB_Mode |
87 | | { |
88 | | public: |
89 | | /** |
90 | | * @param cipher the block cipher to use |
91 | | * @param tag_size is how big the auth tag will be |
92 | | */ |
93 | | OCB_Encryption(std::unique_ptr<BlockCipher> cipher, size_t tag_size = 16) : |
94 | 89 | OCB_Mode(std::move(cipher), tag_size) {} |
95 | | |
96 | | size_t output_length(size_t input_length) const override |
97 | 140 | { return input_length + tag_size(); } |
98 | | |
99 | 0 | size_t minimum_final_size() const override { return 0; } |
100 | | |
101 | | size_t process(uint8_t buf[], size_t size) override; |
102 | | |
103 | | void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override; |
104 | | private: |
105 | | void encrypt(uint8_t input[], size_t blocks); |
106 | | }; |
107 | | |
108 | | class BOTAN_TEST_API OCB_Decryption final : public OCB_Mode |
109 | | { |
110 | | public: |
111 | | /** |
112 | | * @param cipher the block cipher to use |
113 | | * @param tag_size is how big the auth tag will be |
114 | | */ |
115 | | OCB_Decryption(std::unique_ptr<BlockCipher> cipher, size_t tag_size = 16) : |
116 | 139 | OCB_Mode(std::move(cipher), tag_size) {} |
117 | | |
118 | | size_t output_length(size_t input_length) const override |
119 | 79 | { |
120 | 79 | BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input"); |
121 | 79 | return input_length - tag_size(); |
122 | 79 | } |
123 | | |
124 | 80 | size_t minimum_final_size() const override { return tag_size(); } |
125 | | |
126 | | size_t process(uint8_t buf[], size_t size) override; |
127 | | |
128 | | void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override; |
129 | | private: |
130 | | void decrypt(uint8_t input[], size_t blocks); |
131 | | }; |
132 | | |
133 | | } |
134 | | |
135 | | #endif |