triglav 0.1.0

High-performance multi-path networking tool with intelligent uplink management
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

//! Key derivation functions for Triglav.
//!
//! Uses HKDF-SHA256 for all key material derivation.

use hkdf::Hkdf;
use sha2::Sha256;

/// Key schedule for deriving all cryptographic keys.
pub struct KeySchedule;

impl KeySchedule {
    /// Domain separation prefix for all Triglav keys.
    const DOMAIN: &'static [u8] = b"triglav/v1/";

    /// Derive a key using HKDF-SHA256.
    ///
    /// # Arguments
    /// * `ikm` - Input key material
    /// * `salt` - Optional salt (can be empty)
    /// * `info` - Context/label for the key
    /// * `length` - Output key length (max 255 * 32 = 8160 bytes)
    pub fn derive(ikm: &[u8], salt: Option<&[u8]>, info: &[u8], length: usize) -> Vec<u8> {
        let hk = Hkdf::<Sha256>::new(salt, ikm);
        let mut okm = vec![0u8; length];
        hk.expand(info, &mut okm)
            .expect("HKDF output length should be valid");
        okm
    }

    /// Derive a 32-byte key.
    pub fn derive_key(ikm: &[u8], salt: Option<&[u8]>, info: &[u8]) -> [u8; 32] {
        let hk = Hkdf::<Sha256>::new(salt, ikm);
        let mut okm = [0u8; 32];
        hk.expand(info, &mut okm)
            .expect("32-byte HKDF output should be valid");
        okm
    }

    /// Derive a 24-byte nonce.
    pub fn derive_nonce(ikm: &[u8], salt: Option<&[u8]>, info: &[u8]) -> [u8; 24] {
        let hk = Hkdf::<Sha256>::new(salt, ikm);
        let mut okm = [0u8; 24];
        hk.expand(info, &mut okm)
            .expect("24-byte HKDF output should be valid");
        okm
    }

    /// Derive session encryption key from shared secret.
    pub fn session_key(shared_secret: &[u8; 32], session_id: &[u8; 32]) -> [u8; 32] {
        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"session-key".len());
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"session-key");
        Self::derive_key(shared_secret, Some(session_id), &info)
    }

    /// Derive packet encryption key from session key.
    pub fn packet_key(session_key: &[u8; 32], direction: Direction) -> [u8; 32] {
        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"packet-key-".len() + 1);
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"packet-key-");
        info.push(direction as u8);
        Self::derive_key(session_key, None, &info)
    }

    /// Derive MAC key for packet authentication.
    pub fn mac_key(session_key: &[u8; 32]) -> [u8; 32] {
        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"mac-key".len());
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"mac-key");
        Self::derive_key(session_key, None, &info)
    }

    /// Derive handshake binding key.
    pub fn handshake_binding(
        initiator_public: &[u8; 32],
        responder_public: &[u8; 32],
        transcript_hash: &[u8; 32],
    ) -> [u8; 32] {
        let mut ikm = Vec::with_capacity(96);
        ikm.extend_from_slice(initiator_public);
        ikm.extend_from_slice(responder_public);
        ikm.extend_from_slice(transcript_hash);

        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"handshake-binding".len());
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"handshake-binding");

        Self::derive_key(&ikm, None, &info)
    }

    /// Derive uplink-specific key for per-path encryption (optional layer).
    pub fn uplink_key(session_key: &[u8; 32], uplink_id: &str) -> [u8; 32] {
        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"uplink-key/".len() + uplink_id.len());
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"uplink-key/");
        info.extend_from_slice(uplink_id.as_bytes());
        Self::derive_key(session_key, None, &info)
    }

    /// Derive rekey material for session key rotation.
    pub fn rekey(current_key: &[u8; 32], rekey_counter: u64) -> [u8; 32] {
        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"rekey".len());
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"rekey");

        let salt = rekey_counter.to_le_bytes();
        Self::derive_key(current_key, Some(&salt), &info)
    }

    /// Derive auth token from server public key and secret.
    pub fn auth_token(server_pubkey: &[u8; 32], client_secret: &[u8; 32]) -> [u8; 32] {
        let mut ikm = Vec::with_capacity(64);
        ikm.extend_from_slice(server_pubkey);
        ikm.extend_from_slice(client_secret);

        let mut info = Vec::with_capacity(Self::DOMAIN.len() + b"auth-token".len());
        info.extend_from_slice(Self::DOMAIN);
        info.extend_from_slice(b"auth-token");

        Self::derive_key(&ikm, None, &info)
    }
}

/// Direction of data flow for key derivation.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(u8)]
pub enum Direction {
    /// Client to server.
    ClientToServer = 0,
    /// Server to client.
    ServerToClient = 1,
}

#[cfg(test)]
mod tests {
    use super::*;
    use hmac::{Hmac, Mac};
    type HmacSha256 = Hmac<sha2::Sha256>;

    /// HMAC-SHA256 for message authentication (test-only).
    fn hmac_sha256(key: &[u8], data: &[u8]) -> [u8; 32] {
        let mut mac = HmacSha256::new_from_slice(key).expect("HMAC accepts any key length");
        mac.update(data);
        mac.finalize().into_bytes().into()
    }

    /// Verify HMAC-SHA256 in constant time (test-only).
    fn hmac_sha256_verify(key: &[u8], data: &[u8], expected: &[u8; 32]) -> bool {
        let computed = hmac_sha256(key, data);
        crate::crypto::secure_compare(&computed, expected)
    }

    #[test]
    fn test_derive_key() {
        let ikm = b"input key material";
        let salt = b"salt";
        let info = b"context";

        let key1 = KeySchedule::derive_key(ikm, Some(salt), info);
        let key2 = KeySchedule::derive_key(ikm, Some(salt), info);
        assert_eq!(key1, key2);

        // Different info should produce different key
        let key3 = KeySchedule::derive_key(ikm, Some(salt), b"different");
        assert_ne!(key1, key3);
    }

    #[test]
    fn test_session_key() {
        let shared_secret: [u8; 32] = crate::crypto::random_bytes();
        let session_id: [u8; 32] = crate::crypto::random_bytes();

        let key1 = KeySchedule::session_key(&shared_secret, &session_id);
        let key2 = KeySchedule::session_key(&shared_secret, &session_id);
        assert_eq!(key1, key2);
    }

    #[test]
    fn test_packet_key_directions() {
        let session_key: [u8; 32] = crate::crypto::random_bytes();

        let c2s = KeySchedule::packet_key(&session_key, Direction::ClientToServer);
        let s2c = KeySchedule::packet_key(&session_key, Direction::ServerToClient);

        // Different directions should produce different keys
        assert_ne!(c2s, s2c);
    }

    #[test]
    fn test_rekey() {
        let key: [u8; 32] = crate::crypto::random_bytes();

        let rekey1 = KeySchedule::rekey(&key, 1);
        let rekey2 = KeySchedule::rekey(&key, 2);

        assert_ne!(key, rekey1);
        assert_ne!(rekey1, rekey2);
    }

    #[test]
    fn test_hmac() {
        let key = b"secret key";
        let data = b"data to authenticate";

        let mac = hmac_sha256(key, data);
        assert!(hmac_sha256_verify(key, data, &mac));

        // Wrong data should fail
        assert!(!hmac_sha256_verify(key, b"wrong data", &mac));
    }
}