ece/crypto/
mod.rs

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
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use crate::error::*;
use std::any::Any;

pub(crate) mod holder;
#[cfg(feature = "backend-openssl")]
mod openssl;

#[cfg(not(feature = "backend-openssl"))]
pub use holder::{set_boxed_cryptographer, set_cryptographer};

pub trait RemotePublicKey: Send + Sync + 'static {
    /// Export the key component in the
    /// binary uncompressed point representation.
    fn as_raw(&self) -> Result<Vec<u8>>;
    /// For downcasting purposes.
    fn as_any(&self) -> &dyn Any;
}

pub trait LocalKeyPair: Send + Sync + 'static {
    /// Export the public key component in the
    /// binary uncompressed point representation.
    fn pub_as_raw(&self) -> Result<Vec<u8>>;
    /// Export the raw components of the keypair.
    fn raw_components(&self) -> Result<EcKeyComponents>;
    /// For downcasting purposes.
    fn as_any(&self) -> &dyn Any;
}

#[derive(Clone, Debug, Eq, PartialEq)]
#[cfg_attr(
    feature = "serializable-keys",
    derive(serde::Serialize, serde::Deserialize)
)]
#[derive(Default)]
pub enum EcCurve {
    #[default]
    P256,
}

#[derive(Clone, Debug, Eq, PartialEq)]
#[cfg_attr(
    feature = "serializable-keys",
    derive(serde::Serialize, serde::Deserialize)
)]
pub struct EcKeyComponents {
    // The curve is only kept in case the ECE standard changes in the future.
    curve: EcCurve,
    // The `d` value of the EC Key.
    private_key: Vec<u8>,
    // The uncompressed x,y-representation of the public component of the EC Key.
    public_key: Vec<u8>,
}

impl EcKeyComponents {
    pub fn new<T: Into<Vec<u8>>>(private_key: T, public_key: T) -> Self {
        EcKeyComponents {
            private_key: private_key.into(),
            public_key: public_key.into(),
            curve: Default::default(),
        }
    }
    pub fn curve(&self) -> &EcCurve {
        &self.curve
    }
    /// The `d` value of the EC Key.
    pub fn private_key(&self) -> &[u8] {
        &self.private_key
    }
    /// The uncompressed x,y-representation of the public component of the EC Key.
    pub fn public_key(&self) -> &[u8] {
        &self.public_key
    }
}

pub trait Cryptographer: Send + Sync + 'static {
    /// Generate a random ephemeral local key pair.
    fn generate_ephemeral_keypair(&self) -> Result<Box<dyn LocalKeyPair>>;
    /// Import a local keypair from its raw components.
    fn import_key_pair(&self, components: &EcKeyComponents) -> Result<Box<dyn LocalKeyPair>>;
    /// Import the public key component in the binary uncompressed point representation.
    fn import_public_key(&self, raw: &[u8]) -> Result<Box<dyn RemotePublicKey>>;
    fn compute_ecdh_secret(
        &self,
        remote: &dyn RemotePublicKey,
        local: &dyn LocalKeyPair,
    ) -> Result<Vec<u8>>;
    fn hkdf_sha256(&self, salt: &[u8], secret: &[u8], info: &[u8], len: usize) -> Result<Vec<u8>>;
    /// Should return [ciphertext, auth_tag].
    fn aes_gcm_128_encrypt(&self, key: &[u8], iv: &[u8], data: &[u8]) -> Result<Vec<u8>>;
    fn aes_gcm_128_decrypt(
        &self,
        key: &[u8],
        iv: &[u8],
        ciphertext_and_tag: &[u8],
    ) -> Result<Vec<u8>>;
    fn random_bytes(&self, dest: &mut [u8]) -> Result<()>;
}

/// Run a small suite of tests to check that a `Cryptographer` backend is working correctly.
///
/// You should only use this is you're implementing a custom `Cryptographer` and want to check
/// that it is working as intended. This function will panic if the tests fail.
///
#[cfg(any(test, feature = "backend-test-helper"))]
pub fn test_cryptographer<T: Cryptographer>(cryptographer: T) {
    use crate::{aes128gcm, common::WebPushParams};

    // These are test data from the RFC.
    let plaintext = "When I grow up, I want to be a watermelon";
    let ciphertext = hex::decode("0c6bfaadad67958803092d454676f397000010004104fe33f4ab0dea71914db55823f73b54948f41306d920732dbb9a59a53286482200e597a7b7bc260ba1c227998580992e93973002f3012a28ae8f06bbb78e5ec0ff297de5b429bba7153d3a4ae0caa091fd425f3b4b5414add8ab37a19c1bbb05cf5cb5b2a2e0562d558635641ec52812c6c8ff42e95ccb86be7cd").unwrap();

    // First, a trial encryption.
    let private_key =
        hex::decode("c9f58f89813e9f8e872e71f42aa64e1757c9254dcc62b72ddc010bb4043ea11c").unwrap();
    let public_key = hex::decode("04fe33f4ab0dea71914db55823f73b54948f41306d920732dbb9a59a53286482200e597a7b7bc260ba1c227998580992e93973002f3012a28ae8f06bbb78e5ec0f").unwrap();
    let ec_key = EcKeyComponents::new(private_key, public_key);
    let local_key_pair = cryptographer.import_key_pair(&ec_key).unwrap();

    let remote_pub_key = hex::decode("042571b2becdfde360551aaf1ed0f4cd366c11cebe555f89bcb7b186a53339173168ece2ebe018597bd30479b86e3c8f8eced577ca59187e9246990db682008b0e").unwrap();
    let remote_pub_key = cryptographer.import_public_key(&remote_pub_key).unwrap();
    let auth_secret = hex::decode("05305932a1c7eabe13b6cec9fda48882").unwrap();

    let params = WebPushParams {
        rs: 4096,
        pad_length: 0,
        salt: Some(hex::decode("0c6bfaadad67958803092d454676f397").unwrap()),
    };

    assert_eq!(
        aes128gcm::encrypt(
            &*local_key_pair,
            &*remote_pub_key,
            &auth_secret,
            plaintext.as_bytes(),
            params,
        )
        .unwrap(),
        ciphertext
    );

    // Now, a trial decryption.
    let private_key =
        hex::decode("ab5757a70dd4a53e553a6bbf71ffefea2874ec07a6b379e3c48f895a02dc33de").unwrap();
    let public_key = hex::decode("042571b2becdfde360551aaf1ed0f4cd366c11cebe555f89bcb7b186a53339173168ece2ebe018597bd30479b86e3c8f8eced577ca59187e9246990db682008b0e").unwrap();
    let ec_key = EcKeyComponents::new(private_key, public_key);
    let local_key_pair = cryptographer.import_key_pair(&ec_key).unwrap();

    assert_eq!(
        aes128gcm::decrypt(&*local_key_pair, &auth_secret, ciphertext.as_ref(),).unwrap(),
        plaintext.as_bytes()
    );
}

#[cfg(all(test, feature = "backend-openssl"))]
mod tests {
    use super::*;

    // All of the tests in this crate exercise the default backend, so running this here
    // doesn't tell us anyting more about the default backend. Instead, it tells us whether
    // the `test_cryptographer` function is working correctly!
    #[test]
    fn test_default_cryptograher() {
        test_cryptographer(super::openssl::OpensslCryptographer);
    }
}