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
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
#![no_std]
#![doc(
html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/26acc39f/logo.svg",
html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/26acc39f/logo.svg"
)]
#![forbid(unsafe_code)]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![warn(missing_docs, rust_2018_idioms)]
pub use digest::{self, Mac};
use cipher::{BlockBackend, BlockCipher, BlockClosure, BlockEncryptMut};
use core::fmt;
use dbl::Dbl;
use digest::{
block_buffer::Lazy,
core_api::{
AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, CoreWrapper, FixedOutputCore,
UpdateCore,
},
crypto_common::{InnerInit, InnerUser},
generic_array::{
typenum::{IsLess, Le, NonZero, U256},
ArrayLength, GenericArray,
},
MacMarker, Output, OutputSizeUser, Reset,
};
#[cfg(feature = "zeroize")]
use cipher::zeroize::{Zeroize, ZeroizeOnDrop};
pub type Cmac<C> = CoreWrapper<CmacCore<C>>;
#[derive(Clone)]
pub struct CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
cipher: C,
state: Block<C>,
}
impl<C> BlockSizeUser for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
type BlockSize = C::BlockSize;
}
impl<C> OutputSizeUser for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
type OutputSize = C::BlockSize;
}
impl<C> InnerUser for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
type Inner = C;
}
impl<C> MacMarker for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
}
impl<C> InnerInit for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
#[inline]
fn inner_init(cipher: C) -> Self {
let state = Default::default();
Self { cipher, state }
}
}
impl<C> BufferKindUser for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
type BufferKind = Lazy;
}
impl<C> UpdateCore for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
#[inline]
fn update_blocks(&mut self, blocks: &[Block<Self>]) {
struct Ctx<'a, N: ArrayLength<u8>> {
state: &'a mut Block<Self>,
blocks: &'a [Block<Self>],
}
impl<'a, N: ArrayLength<u8>> BlockSizeUser for Ctx<'a, N> {
type BlockSize = N;
}
impl<'a, N: ArrayLength<u8>> BlockClosure for Ctx<'a, N> {
#[inline(always)]
fn call<B: BlockBackend<BlockSize = Self::BlockSize>>(self, backend: &mut B) {
for block in self.blocks {
xor(self.state, block);
backend.proc_block((self.state).into());
}
}
}
let Self { cipher, state } = self;
cipher.encrypt_with_backend_mut(Ctx { state, blocks })
}
}
impl<C> Reset for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
#[inline(always)]
fn reset(&mut self) {
self.state = Default::default();
}
}
impl<C> FixedOutputCore for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
C::BlockSize: IsLess<U256>,
Le<C::BlockSize, U256>: NonZero,
{
#[inline]
fn finalize_fixed_core(&mut self, buffer: &mut Buffer<Self>, out: &mut Output<Self>) {
let Self { state, cipher } = self;
let pos = buffer.get_pos();
let buf = buffer.pad_with_zeros();
let mut subkey = Default::default();
cipher.encrypt_block_mut(&mut subkey);
let key1 = subkey.dbl();
xor(state, buf);
if pos == buf.len() {
xor(state, &key1);
} else {
state[pos] ^= 0x80;
let key2 = key1.dbl();
xor(state, &key2);
}
cipher.encrypt_block_mut(state);
out.copy_from_slice(state);
}
}
impl<C> AlgorithmName for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone + AlgorithmName,
Block<C>: Dbl,
{
fn write_alg_name(f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("Cmac<")?;
<C as AlgorithmName>::write_alg_name(f)?;
f.write_str(">")
}
}
impl<C> fmt::Debug for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone + AlgorithmName,
Block<C>: Dbl,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("CmacCore<")?;
<C as AlgorithmName>::write_alg_name(f)?;
f.write_str("> { ... }")
}
}
#[cfg(feature = "zeroize")]
#[cfg_attr(docsrs, doc(cfg(feature = "zeroize")))]
impl<C> Drop for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone,
Block<C>: Dbl,
{
fn drop(&mut self) {
self.state.zeroize();
}
}
#[cfg(feature = "zeroize")]
#[cfg_attr(docsrs, doc(cfg(feature = "zeroize")))]
impl<C> ZeroizeOnDrop for CmacCore<C>
where
C: BlockCipher + BlockEncryptMut + Clone + ZeroizeOnDrop,
Block<C>: Dbl,
{
}
#[inline(always)]
fn xor<N: ArrayLength<u8>>(buf: &mut GenericArray<u8, N>, data: &GenericArray<u8, N>) {
for i in 0..N::USIZE {
buf[i] ^= data[i];
}
}