1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/*
* ECB Mode
* (C) 1999-2009,2013 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/ecb.h>
#include <botan/loadstor.h>
#include <botan/internal/xor_buf.h>
#include <botan/internal/rounding.h>
namespace Botan {
ECB_Mode::ECB_Mode(BlockCipher* cipher, BlockCipherModePaddingMethod* padding) :
m_cipher(cipher),
m_padding(padding)
{
if(!m_padding->valid_blocksize(cipher->block_size()))
throw std::invalid_argument("Padding " + m_padding->name() +
" cannot be used with " +
cipher->name() + "/ECB");
}
void ECB_Mode::clear()
{
m_cipher->clear();
}
std::string ECB_Mode::name() const
{
return cipher().name() + "/ECB/" + padding().name();
}
size_t ECB_Mode::update_granularity() const
{
return cipher().parallel_bytes();
}
Key_Length_Specification ECB_Mode::key_spec() const
{
return cipher().key_spec();
}
size_t ECB_Mode::default_nonce_length() const
{
return 0;
}
bool ECB_Mode::valid_nonce_length(size_t n) const
{
return (n == 0);
}
void ECB_Mode::key_schedule(const byte key[], size_t length)
{
m_cipher->set_key(key, length);
}
secure_vector<byte> ECB_Mode::start(const byte[], size_t nonce_len)
{
if(!valid_nonce_length(nonce_len))
throw Invalid_IV_Length(name(), nonce_len);
return secure_vector<byte>();
}
size_t ECB_Encryption::minimum_final_size() const
{
return 0;
}
size_t ECB_Encryption::output_length(size_t input_length) const
{
return round_up(input_length, cipher().block_size());
}
void ECB_Encryption::update(secure_vector<byte>& buffer, size_t offset)
{
BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
const size_t sz = buffer.size() - offset;
byte* buf = &buffer[offset];
const size_t BS = cipher().block_size();
BOTAN_ASSERT(sz % BS == 0, "ECB input is full blocks");
const size_t blocks = sz / BS;
cipher().encrypt_n(&buf[0], &buf[0], blocks);
}
void ECB_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
{
BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
const size_t sz = buffer.size() - offset;
const size_t BS = cipher().block_size();
const size_t bytes_in_final_block = sz % BS;
padding().add_padding(buffer, bytes_in_final_block, BS);
if(buffer.size() % BS)
throw std::runtime_error("Did not pad to full block size in " + name());
update(buffer, offset);
}
size_t ECB_Decryption::output_length(size_t input_length) const
{
return input_length;
}
size_t ECB_Decryption::minimum_final_size() const
{
return cipher().block_size();
}
void ECB_Decryption::update(secure_vector<byte>& buffer, size_t offset)
{
BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
const size_t sz = buffer.size() - offset;
byte* buf = &buffer[offset];
const size_t BS = cipher().block_size();
BOTAN_ASSERT(sz % BS == 0, "Input is full blocks");
size_t blocks = sz / BS;
cipher().decrypt_n(&buf[0], &buf[0], blocks);
}
void ECB_Decryption::finish(secure_vector<byte>& buffer, size_t offset)
{
BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
const size_t sz = buffer.size() - offset;
const size_t BS = cipher().block_size();
if(sz == 0 || sz % BS)
throw Decoding_Error(name() + ": Ciphertext not a multiple of block size");
update(buffer, offset);
const size_t pad_bytes = BS - padding().unpad(&buffer[buffer.size()-BS], BS);
buffer.resize(buffer.size() - pad_bytes); // remove padding
}
}
|
