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

use super::generics::Encryption;
use crate::EciesError;
use chacha20poly1305::aead::{Aead, Payload};
use chacha20poly1305::KeyInit;

#[cfg(feature = "ECIES-MAC")]
use crate::markers::{EciesMacDecryptionSupport, EciesMacEncryptionSupport};
#[cfg(feature = "ECIES-MAC")]
impl EciesMacEncryptionSupport for XChaCha20Poly1305 {}
#[cfg(feature = "ECIES-MAC")]
impl EciesMacDecryptionSupport for XChaCha20Poly1305 {}

#[cfg(feature = "ECIES-AEAD")]
use crate::markers::{EciesAeadDecryptionSupport, EciesAeadEncryptionSupport};
#[cfg(feature = "ECIES-AEAD")]
impl EciesAeadEncryptionSupport for XChaCha20Poly1305 {}
#[cfg(feature = "ECIES-AEAD")]
impl EciesAeadDecryptionSupport for XChaCha20Poly1305 {}

#[cfg(feature = "ECIES-SYN")]
use crate::markers::{EciesSynDecryptionSupport, EciesSynEncryptionSupport};
#[cfg(feature = "ECIES-SYN")]
impl EciesSynEncryptionSupport for XChaCha20Poly1305 {}
#[cfg(feature = "ECIES-SYN")]
impl EciesSynDecryptionSupport for XChaCha20Poly1305 {}

/// Marker for using the `XChaCha20-Poly1305` algorithm for encryption
///
/// XChaCha20-Poly1305 is provided by [chacha20poly1305](https://crates.io/crates/chacha20poly1305)
pub struct XChaCha20Poly1305;

impl Encryption for XChaCha20Poly1305 {
    const ENCRYPTION_KEY_LEN: usize = 32;
    const ENCRYPTION_NONCE_LEN: usize = 24;

    fn encrypt(key: &[u8], nonce: &[u8], plaintext: &[u8]) -> Result<Vec<u8>, EciesError> {
        let enc = chacha20poly1305::XChaCha20Poly1305::new_from_slice(key)
            .map_err(|_| EciesError::BadData)?;

        enc.encrypt(
            nonce.into(),
            Payload {
                msg: plaintext,
                aad: b"",
            },
        )
        .map_err(|_| EciesError::EncryptionError)
    }

    fn decrypt(key: &[u8], nonce: &[u8], ciphertext: &[u8]) -> Result<Vec<u8>, EciesError> {
        let dec = chacha20poly1305::XChaCha20Poly1305::new_from_slice(key)
            .map_err(|_| EciesError::BadData)?;

        dec.decrypt(
            nonce.into(),
            Payload {
                msg: ciphertext,
                aad: b"",
            },
        )
        .map_err(|_| EciesError::DecryptionError)
    }
}