zuc 0.4.1

ZUC Stream Cipher Algorithms
Documentation 
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

use super::Zuc256Keystream;

use crate::internal::mac::{MacCore, MacKeyPair, MacWord};

use core::mem::size_of;

use stdx::default::default;

pub trait MacTag: MacWord {}
impl MacTag for u32 {}
impl MacTag for u64 {}
impl MacTag for u128 {}

/// ZUC256 MAC generator
/// ([ZUC256-version1.1](http://www.is.cas.cn/ztzl2016/zouchongzhi/201801/W020180416526664982687.pdf))
pub struct Zuc256Mac<T: MacTag>(MacCore<Zuc256Keystream, T>);

impl<T: MacTag> Zuc256Mac<T> {
    /// Compute the MAC of a message
    ///
    /// ## Input
    /// | name   | size     | description                     |
    /// | ------ | -------- | ------------------------------- |
    /// | T      | -        | type of the output MAC          |
    /// | ik     | 256 bits | integrity key                   |
    /// | iv     | 184 bits | initial vector                  |
    /// | msg    | -        | the input message               |
    /// | bitlen | -        | bit length of the input message |
    ///
    /// ## Output
    /// MAC (Message Authentication Code) with type `T`
    #[must_use]
    pub fn compute(ik: &[u8; 32], iv: &[u8; 23], msg: &[u8], bitlen: usize) -> T {
        Self::new(ik, iv).finish(msg, bitlen)
    }

    /// Create a new ZUC256 MAC generator
    #[must_use]
    pub fn new(ik: &[u8; 32], iv: &[u8; 23]) -> Self {
        let d = match size_of::<T>() {
            4 => &D_32,
            8 => &D_64,
            16 => &D_128,
            _ => unreachable!(),
        };

        let mut zuc = Zuc256Keystream::new_with_d(ik, iv, d);
        let tag: T = T::gen_word(&mut zuc);
        let key: T::KeyPair = T::KeyPair::gen_key_pair(&mut zuc);

        Self(MacCore {
            zuc,
            key,
            tag,
            rem: default(),
            cnt: 0,
        })
    }

    /// Update the MAC generator with the bytes of a message
    pub fn update(&mut self, msg: &[u8]) {
        self.0.update(msg);
    }

    /// Finish the MAC generation and return the MAC
    pub fn finish(mut self, tail: &[u8], bitlen: usize) -> T {
        let _ = self.0.finish(tail, bitlen);
        self.0.tag ^= self.0.key.high();
        self.0.tag
    }
}

/// d constant for 32bit MAC
const D_32: [u8; 16] = [
    0b010_0010, 0b010_1111, 0b010_0101, 0b010_1010, 0b110_1101, 0b100_0000, 0b100_0000, 0b100_0000,
    0b100_0000, 0b100_0000, 0b100_0000, 0b100_0000, 0b100_0000, 0b101_0010, 0b001_0000, 0b011_0000,
];

/// d constant for 64bit MAC
const D_64: [u8; 16] = [
    0b010_0011, 0b010_1111, 0b010_0100, 0b010_1010, 0b110_1101, 0b100_0000, 0b100_0000, 0b100_0000,
    0b100_0000, 0b100_0000, 0b100_0000, 0b100_0000, 0b100_0000, 0b101_0010, 0b001_0000, 0b011_0000,
];

/// d constant for 128bit MAC
const D_128: [u8; 16] = [
    0b010_0011, 0b010_1111, 0b010_0101, 0b010_1010, 0b110_1101, 0b100_0000, 0b100_0000, 0b100_0000,
    0b100_0000, 0b100_0000, 0b100_0000, 0b100_0000, 0b100_0000, 0b101_0010, 0b001_0000, 0b011_0000,
];

impl<T: MacTag> digest::Update for Zuc256Mac<T> {
    fn update(&mut self, data: &[u8]) {
        Zuc256Mac::update(self, data);
    }
}

impl<T: MacTag> digest::OutputSizeUser for Zuc256Mac<T> {
    type OutputSize = <T as MacWord>::ByteSize;
}

impl<T: MacTag> digest::FixedOutput for Zuc256Mac<T> {
    fn finalize_into(self, out: &mut digest::Output<Self>) {
        let tag = self.finish(&[], 0);
        *out = tag.to_be_array();
    }
}

impl<T: MacTag> digest::MacMarker for Zuc256Mac<T> {}

#[cfg(test)]
mod tests {
    use super::*;

    /// Examples
    ///
    /// FROM <http://www.is.cas.cn/ztzl2016/zouchongzhi/201801/W020180416526664982687.pdf>
    struct Example {
        k: [u8; 32],
        iv: [u8; 23],
        length: u32,
        m: &'static [u8],
        expected_32: u32,
        expected_64: u64,
        expected_128: u128,
    }

    static EXAMPLE_MAC_1: Example = Example {
        k: [0; 32],
        iv: [0; 23],
        length: 400,
        m: &[0; 50],
        expected_32: 0x9b97_2a74,
        expected_64: 0x673e_5499_0034_d38c,
        expected_128: 0xd85e_54bb_cb96_0096_7084_c952_a165_4b26,
    };

    static EXAMPLE_MAC_2: Example = Example {
        k: [0; 32],
        iv: [0; 23],
        length: 4000,
        m: &[0x11; 500],
        expected_32: 0x8754_f5cf,
        expected_64: 0x130d_c225_e722_40cc,
        expected_128: 0xdf1e_8307_b31c_c62b_eca1_ac6f_8190_c22f,
    };

    static EXAMPLE_MAC_3: Example = Example {
        k: [0xff; 32],
        iv: [0xff; 23],
        length: 400,
        m: &[0x00; 50],
        expected_32: 0x1f30_79b4,
        expected_64: 0x8c71_394d_3995_7725,
        expected_128: 0xa35b_b274_b567_c48b_2831_9f11_1af3_4fbd,
    };

    static EXAMPLE_MAC_4: Example = Example {
        k: [0xff; 32],
        iv: [0xff; 23],
        length: 4000,
        m: &[0x11; 500],
        expected_32: 0x5c7c_8b88,
        expected_64: 0xea1d_ee54_4bb6_223b,
        expected_128: 0x3a83_b554_be40_8ca5_4941_24ed_9d47_3205,
    };

    static ALL_EXAMPLES: &[&Example] = &[
        &EXAMPLE_MAC_1,
        &EXAMPLE_MAC_2,
        &EXAMPLE_MAC_3,
        &EXAMPLE_MAC_4,
    ];

    #[test]
    fn examples() {
        for x in ALL_EXAMPLES {
            let mac_32 = <Zuc256Mac<u32>>::compute(&x.k, &x.iv, x.m, x.length as usize);
            assert_eq!(mac_32, x.expected_32);

            let mac_64 = <Zuc256Mac<u64>>::compute(&x.k, &x.iv, x.m, x.length as usize);
            assert_eq!(mac_64, x.expected_64);

            let mac_128 = <Zuc256Mac<u128>>::compute(&x.k, &x.iv, x.m, x.length as usize);
            assert_eq!(mac_128, x.expected_128);
        }
    }

    #[test]
    fn special_bitlen() {
        let x = &EXAMPLE_MAC_2;
        let bitlen = 145;
        let mac_32 = <Zuc256Mac<u32>>::compute(&x.k, &x.iv, x.m, bitlen);
        let expected_32 = 0x213e_1ce5; // generated from GmSSL
        assert_eq!(mac_32, expected_32, "actual = {mac_32:08x}");
    }

    #[test]
    fn zero_bitlen() {
        let examples = [&EXAMPLE_MAC_1, &EXAMPLE_MAC_2];

        for x in examples {
            let bitlen = 0;
            let mac_32 = <Zuc256Mac<u32>>::compute(&x.k, &x.iv, x.m, bitlen);
            let expected_32 = 0x68dc_aaba; // generated from GmSSL
            assert_eq!(mac_32, expected_32, "actual = {mac_32:08x}");
        }
    }

    #[test]
    fn streaming() {
        fn check<T: MacTag>(x: &Example, parts: &[usize], expected: T) {
            let mut mac = Zuc256Mac::<T>::new(&x.k, &x.iv);

            for i in 1..parts.len() {
                mac.update(&x.m[parts[i - 1]..parts[i]]);
            }

            let last = parts[parts.len() - 1];
            let ans = mac.finish(&x.m[last..], x.length as usize - last * 8);

            assert_eq!(ans, expected);
        }

        for x in ALL_EXAMPLES {
            for bp in 0..(x.length as usize) / 8 {
                check(x, &[0, bp], x.expected_32);
                check(x, &[0, bp], x.expected_64);
                check(x, &[0, bp], x.expected_128);
            }
        }

        for x in ALL_EXAMPLES {
            for bp1 in 0..16 {
                for bp2 in 16..32 {
                    check(x, &[0, bp1, bp2], x.expected_32);
                    check(x, &[0, bp1, bp2], x.expected_64);
                    check(x, &[0, bp1, bp2], x.expected_128);
                }
            }
        }
    }

    #[test]
    fn test_digest() {
        fn require_digest_mac<T: digest::Mac>() {}

        require_digest_mac::<Zuc256Mac<u32>>();
        require_digest_mac::<Zuc256Mac<u64>>();
        require_digest_mac::<Zuc256Mac<u128>>();
    }
}