Botan 2.19.3
Crypto and TLS for C&
ocb.h
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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
15
16namespace Botan {
17
18class BlockCipher;
19class L_computer;
20
21/**
22* OCB Mode (base class for OCB_Encryption and OCB_Decryption). Note
23* that OCB is patented, but is freely licensed in some circumstances.
24*
25* @see "The OCB Authenticated-Encryption Algorithm" RFC 7253
26* https://tools.ietf.org/html/rfc7253
27* @see "OCB For Block Ciphers Without 128-Bit Blocks"
28* (draft-krovetz-ocb-wide-d3) for the extension of OCB to
29* block ciphers with larger block sizes.
30* @see Free Licenses http://www.cs.ucdavis.edu/~rogaway/ocb/license.htm
31* @see OCB home page http://www.cs.ucdavis.edu/~rogaway/ocb
32*/
34 {
35 public:
36 void set_associated_data(const uint8_t ad[], size_t ad_len) override;
37
38 std::string name() const override;
39
40 size_t update_granularity() const override;
41
42 Key_Length_Specification key_spec() const override;
43
44 bool valid_nonce_length(size_t) const override;
45
46 size_t tag_size() const override { return m_tag_size; }
47
48 void clear() override;
49
50 void reset() override;
51
52 ~OCB_Mode();
53 protected:
54 /**
55 * @param cipher the block cipher to use
56 * @param tag_size is how big the auth tag will be
57 */
58 OCB_Mode(BlockCipher* cipher, size_t tag_size);
59
60 size_t block_size() const { return m_block_size; }
61 size_t par_blocks() const { return m_par_blocks; }
62 size_t par_bytes() const { return m_checksum.size(); }
63
64 // fixme make these private
65 std::unique_ptr<BlockCipher> m_cipher;
66 std::unique_ptr<L_computer> m_L;
67
68 size_t m_block_index = 0;
69
72 private:
73 void start_msg(const uint8_t nonce[], size_t nonce_len) override;
74
75 void key_schedule(const uint8_t key[], size_t length) override;
76
77 const secure_vector<uint8_t>& update_nonce(const uint8_t nonce[], size_t nonce_len);
78
79 const size_t m_tag_size;
80 const size_t m_block_size;
81 const size_t m_par_blocks;
82 secure_vector<uint8_t> m_last_nonce;
83 secure_vector<uint8_t> m_stretch;
84 secure_vector<uint8_t> m_nonce_buf;
86 };
87
89 {
90 public:
91 /**
92 * @param cipher the block cipher to use
93 * @param tag_size is how big the auth tag will be
94 */
95 OCB_Encryption(BlockCipher* cipher, size_t tag_size = 16) :
96 OCB_Mode(cipher, tag_size) {}
97
98 size_t output_length(size_t input_length) const override
99 { return input_length + tag_size(); }
100
101 size_t minimum_final_size() const override { return 0; }
102
103 size_t process(uint8_t buf[], size_t size) override;
104
105 void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
106 private:
107 void encrypt(uint8_t input[], size_t blocks);
108 };
109
111 {
112 public:
113 /**
114 * @param cipher the block cipher to use
115 * @param tag_size is how big the auth tag will be
116 */
117 OCB_Decryption(BlockCipher* cipher, size_t tag_size = 16) :
118 OCB_Mode(cipher, tag_size) {}
119
120 size_t output_length(size_t input_length) const override
121 {
122 BOTAN_ASSERT(input_length >= tag_size(), "Sufficient input");
123 return input_length - tag_size();
124 }
125
126 size_t minimum_final_size() const override { return tag_size(); }
127
128 size_t process(uint8_t buf[], size_t size) override;
129
130 void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
131 private:
132 void decrypt(uint8_t input[], size_t blocks);
133 };
134
135}
136
137#endif
#define BOTAN_ASSERT(expr, assertion_made)
Definition assert.h:55
virtual void set_associated_data(const uint8_t ad[], size_t ad_len)=0
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0
virtual size_t process(uint8_t msg[], size_t msg_len)=0
virtual void reset()=0
virtual void finish(secure_vector< uint8_t > &final_block, size_t offset=0)=0
virtual size_t tag_size() const
virtual size_t update_granularity() const =0
virtual bool valid_nonce_length(size_t nonce_len) const =0
size_t output_length(size_t input_length) const override
Definition ocb.h:120
OCB_Decryption(BlockCipher *cipher, size_t tag_size=16)
Definition ocb.h:117
size_t minimum_final_size() const override
Definition ocb.h:126
size_t minimum_final_size() const override
Definition ocb.h:101
size_t output_length(size_t input_length) const override
Definition ocb.h:98
OCB_Encryption(BlockCipher *cipher, size_t tag_size=16)
Definition ocb.h:95
size_t par_bytes() const
Definition ocb.h:62
size_t block_size() const
Definition ocb.h:60
size_t par_blocks() const
Definition ocb.h:61
secure_vector< uint8_t > m_checksum
Definition ocb.h:70
size_t tag_size() const override
Definition ocb.h:46
std::unique_ptr< BlockCipher > m_cipher
Definition ocb.h:65
secure_vector< uint8_t > m_ad_hash
Definition ocb.h:71
std::unique_ptr< L_computer > m_L
Definition ocb.h:66
virtual std::string name() const =0
virtual void clear()=0
virtual Key_Length_Specification key_spec() const =0
int(* final)(unsigned char *, CTX *)
#define BOTAN_PUBLIC_API(maj, min)
Definition compiler.h:31
#define BOTAN_FUTURE_INTERNAL_HEADER(hdr)
Definition compiler.h:136
std::vector< T, secure_allocator< T > > secure_vector
Definition secmem.h:65