Botan 2.19.2
Crypto and TLS for C&
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
17namespace Botan {
18
19class BlockCipher;
20class StreamCipher;
21class GHASH;
22
23/**
24* GCM Mode
25*/
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
#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 std::string provider() const
Definition: cipher_mode.h:180
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
Definition: cipher_mode.h:174
virtual size_t update_granularity() const =0
virtual bool valid_nonce_length(size_t nonce_len) const =0
size_t minimum_final_size() const override
Definition: gcm.h:108
GCM_Decryption(BlockCipher *cipher, size_t tag_size=16)
Definition: gcm.h:99
size_t output_length(size_t input_length) const override
Definition: gcm.h:102
size_t output_length(size_t input_length) const override
Definition: gcm.h:79
GCM_Encryption(BlockCipher *cipher, size_t tag_size=16)
Definition: gcm.h:76
size_t minimum_final_size() const override
Definition: gcm.h:82
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:57
const size_t m_tag_size
Definition: gcm.h:53
const std::string m_cipher_name
Definition: gcm.h:54
std::unique_ptr< StreamCipher > m_ctr
Definition: gcm.h:56
size_t tag_size() const override
Definition: gcm.h:39
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
Definition: alg_id.cpp:13
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65