aws-lc-rs 1.0.2

aws-lc-rs is a cryptographic library using AWS-LC for its cryptographic operations. This library strives to be API-compatible with the popular Rust library named ring.
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

// Copyright 2018 Brian Smith.
// SPDX-License-Identifier: ISC
// Modifications copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0 OR ISC

use crate::endian::{ArrayEncoding, BigEndian, Encoding};
use crate::error;
use std::convert::TryInto;
use std::mem::transmute_copy;

/// A nonce for a single AEAD opening or sealing operation.
///
/// The user must ensure, for a particular key, that each nonce is unique.
///
/// `Nonce` intentionally doesn't implement `Clone` to ensure that each one is
/// consumed at most once.
pub struct Nonce(pub(crate) [u8; NONCE_LEN]);

impl Nonce {
    /// Constructs a `Nonce` with the given value, assuming that the value is
    /// unique for the lifetime of the key it is being used with.
    ///
    /// Fails if `value` isn't `NONCE_LEN` bytes long.
    /// # Errors
    /// `error::Unspecified` when byte slice length is not `NONCE_LEN`
    #[inline]
    pub fn try_assume_unique_for_key(value: &[u8]) -> Result<Self, error::Unspecified> {
        let value: &[u8; NONCE_LEN] = value.try_into()?;
        Ok(Self::assume_unique_for_key(*value))
    }

    /// Constructs a `Nonce` with the given value, assuming that the value is
    /// unique for the lifetime of the key it is being used with.
    #[inline]
    #[must_use]
    pub fn assume_unique_for_key(value: [u8; NONCE_LEN]) -> Self {
        Self(value)
    }
}

impl AsRef<[u8; NONCE_LEN]> for Nonce {
    #[inline]
    fn as_ref(&self) -> &[u8; NONCE_LEN] {
        &self.0
    }
}

impl From<&[u8; NONCE_LEN]> for Nonce {
    #[inline]
    fn from(bytes: &[u8; NONCE_LEN]) -> Self {
        Nonce(bytes.to_owned())
    }
}

impl From<&[u32; NONCE_LEN / 4]> for Nonce {
    #[inline]
    fn from(values: &[u32; NONCE_LEN / 4]) -> Self {
        unsafe {
            let bytes: [u8; NONCE_LEN] = transmute_copy(values);
            Nonce(bytes)
        }
    }
}

impl From<BigEndian<u32>> for Nonce {
    #[inline]
    fn from(number: BigEndian<u32>) -> Self {
        let nonce = [BigEndian::ZERO, BigEndian::ZERO, number];
        Nonce(*(nonce.as_byte_array()))
    }
}

pub const IV_LEN: usize = 16;
impl From<&[u8; IV_LEN]> for Nonce {
    #[inline]
    fn from(bytes: &[u8; IV_LEN]) -> Self {
        let mut nonce_bytes = [0u8; NONCE_LEN];
        nonce_bytes.copy_from_slice(&bytes[0..NONCE_LEN]);
        Nonce(nonce_bytes)
    }
}

/// All the AEADs we support use 96-bit nonces.
pub const NONCE_LEN: usize = 96 / 8;

#[cfg(test)]
mod tests {

    #[test]
    fn test_nonce_from_byte_array() {
        use crate::aead::nonce::IV_LEN;
        use crate::aead::Nonce;
        let iv: [u8; IV_LEN] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];
        let nonce = Nonce::from(&iv);

        assert_eq!(&[1u8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], nonce.as_ref());
    }
}