ciranda 0.1.2

A deterministic password generator
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

use argon2::{Algorithm, Argon2, ParamsBuilder};
use blake3::Hasher;

use crate::Argon2Settings;

const SALT_SIZE: usize = 16;
pub(crate) const KEY_SIZE: usize = 64;
const SALT_DOMAIN: &[u8] = b"ciranda:v0:salt";

pub(crate) type Salt = [u8; SALT_SIZE];
pub(crate) type Key = [u8; KEY_SIZE];

pub(crate) fn hash_salt(context: &[u8]) -> Salt {
    let mut hasher = Hasher::new();
    hasher.update(SALT_DOMAIN);
    hasher.update(context);
    let hash = hasher.finalize();
    let mut salt = [0u8; SALT_SIZE];
    salt.copy_from_slice(&hash.as_bytes()[..SALT_SIZE]);
    salt
}

pub(crate) fn derive_key(seed: &[u8], salt: &Salt, settings: &Argon2Settings) -> Key {
    let params = ParamsBuilder::new()
        .m_cost(settings.m_cost)
        .t_cost(settings.t_cost)
        .p_cost(settings.p_cost)
        .output_len(KEY_SIZE)
        .build()
        .expect("invalid Argon2 settings");
    let argon2 = Argon2::new(Algorithm::Argon2id, Default::default(), params);
    let mut key = [0u8; KEY_SIZE];
    argon2
        .hash_password_into(seed, salt, &mut key)
        .expect("Argon2 KDF failed");
    key
}

#[cfg(test)]
mod tests {
    use super::{Key, Salt, derive_key, hash_salt};
    use crate::{Argon2Profile, Argon2Settings};

    fn expected_salt_for_context() -> Salt {
        [
            206, 92, 56, 77, 80, 248, 28, 76, 154, 136, 227, 182, 102, 235, 148, 100,
        ]
    }

    fn sample_salt_for_other_context() -> Salt {
        [
            193, 32, 122, 63, 106, 197, 115, 149, 36, 145, 179, 124, 11, 225, 148, 172,
        ]
    }

    fn expected_key_for_seed_and_context() -> Key {
        [
            214, 215, 94, 195, 154, 210, 132, 192, 32, 216, 201, 38, 123, 101, 121, 24, 90, 99, 55,
            172, 98, 1, 7, 141, 23, 177, 78, 16, 33, 224, 11, 46, 196, 174, 141, 3, 7, 67, 239,
            137, 12, 67, 74, 175, 45, 210, 85, 173, 96, 198, 149, 0, 98, 42, 203, 104, 36, 163, 67,
            109, 70, 237, 92, 44,
        ]
    }

    #[test]
    fn hash_salt_produces_known_salt_for_known_context() {
        let salt = hash_salt(b"context");
        assert_eq!(salt, expected_salt_for_context());
    }

    #[test]
    fn hash_salt_produces_different_salts_for_different_contexts() {
        let salt1 = hash_salt(b"context");
        let salt2 = hash_salt(b"context2");
        assert_ne!(salt1, salt2);
        assert_eq!(salt2, sample_salt_for_other_context());
    }

    #[test]
    fn derive_key_produces_known_key_for_known_seed_and_context() {
        let settings = Argon2Profile::Development.settings();
        let context = expected_salt_for_context();
        let key = derive_key(b"seed", &context, &settings);
        assert_eq!(key, expected_key_for_seed_and_context());
    }

    #[test]
    fn derive_key_produces_different_keys_for_different_seeds() {
        let settings = Argon2Profile::Development.settings();
        let context = expected_salt_for_context();
        let key1 = derive_key(b"seed", &context, &settings);
        let key2 = derive_key(b"seed2", &context, &settings);
        assert_ne!(key1, key2);
    }

    #[test]
    fn derive_key_produces_different_keys_for_different_contexts() {
        let settings = Argon2Profile::Development.settings();
        let context1 = expected_salt_for_context();
        let context2 = sample_salt_for_other_context();
        let key1 = derive_key(b"seed", &context1, &settings);
        let key2 = derive_key(b"seed", &context2, &settings);
        assert_ne!(key1, key2);
    }

    #[test]
    fn derive_key_produces_different_keys_for_different_memory_params() {
        let settings1 = Argon2Settings::new(8, 1, 1);
        let settings2 = Argon2Settings::new(16, 1, 1);
        let salt = expected_salt_for_context();
        let key1 = derive_key(b"seed", &salt, &settings1);
        let key2 = derive_key(b"seed", &salt, &settings2);
        assert_ne!(key1, key2);
    }

    #[test]
    fn derive_key_produces_different_keys_for_different_time_params() {
        let settings1 = Argon2Settings::new(8, 1, 1);
        let settings2 = Argon2Settings::new(8, 2, 1);
        let salt = expected_salt_for_context();
        let key1 = derive_key(b"seed", &salt, &settings1);
        let key2 = derive_key(b"seed", &salt, &settings2);
        assert_ne!(key1, key2);
    }

    #[test]
    fn derive_key_produces_different_keys_for_different_parallel_params() {
        let settings1 = Argon2Settings::new(16, 1, 1);
        let settings2 = Argon2Settings::new(16, 1, 2);
        let salt = expected_salt_for_context();
        let key1 = derive_key(b"seed", &salt, &settings1);
        let key2 = derive_key(b"seed", &salt, &settings2);
        assert_ne!(key1, key2);
    }
}