wasefire_board_api/crypto/
aead.rs

1// Copyright 2023 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! Authenticated Encryption with Associated Data.
16
17use crypto_common::generic_array::{ArrayLength, GenericArray};
18
19use crate::{Error, Support};
20
21/// Describes how AEAD is supported.
22#[derive(Copy, Clone)]
23pub struct AeadSupport {
24    /// The implementation doesn't copy when the input and output are in distinct buffers.
25    pub no_copy: bool,
26
27    /// The implementation doesn't copy when the input and output are in the same buffer.
28    pub in_place_no_copy: bool,
29}
30
31impl From<AeadSupport> for bool {
32    fn from(value: AeadSupport) -> Self {
33        value.no_copy || value.in_place_no_copy
34    }
35}
36
37/// AEAD interface.
38pub trait Api<Key, Iv>: Support<AeadSupport> + Send
39where
40    Key: ArrayLength<u8>,
41    Iv: ArrayLength<u8>,
42{
43    /// The tag length.
44    type Tag: ArrayLength<u8>;
45
46    /// Encrypts and authenticates a clear text with associated data given a key and IV.
47    ///
48    /// The clear- and cipher-texts must have the same length. If the clear text is omitted, then
49    /// the cipher text is encrypted in place.
50    fn encrypt(
51        key: &Array<Key>, iv: &Array<Iv>, aad: &[u8], clear: Option<&[u8]>, cipher: &mut [u8],
52        tag: &mut Array<Self::Tag>,
53    ) -> Result<(), Error>;
54
55    /// Decrypts and authenticates a cipher text with associated data given a key and IV.
56    ///
57    /// The cipher- and clear-texts must have the same length. If the cipher text is omitted, then
58    /// the clear text is decrypted in place.
59    fn decrypt(
60        key: &Array<Key>, iv: &Array<Iv>, aad: &[u8], cipher: Option<&[u8]>,
61        tag: &Array<Self::Tag>, clear: &mut [u8],
62    ) -> Result<(), Error>;
63}
64
65/// Sequence of N bytes.
66pub type Array<N> = GenericArray<u8, N>;
67
68#[cfg(feature = "internal-software-crypto-aead")]
69mod software {
70    use aead::{AeadCore, AeadInPlace};
71    use crypto_common::{KeyInit, KeySizeUser};
72
73    use super::*;
74
75    impl<T: AeadInPlace> Support<AeadSupport> for T {
76        const SUPPORT: AeadSupport = AeadSupport { no_copy: false, in_place_no_copy: true };
77    }
78
79    impl<Key, Iv, T> Api<Key, Iv> for T
80    where
81        T: Send + KeyInit + AeadInPlace,
82        T: KeySizeUser<KeySize = Key>,
83        T: AeadCore<NonceSize = Iv>,
84        Key: ArrayLength<u8>,
85        Iv: ArrayLength<u8>,
86    {
87        type Tag = T::TagSize;
88
89        fn encrypt(
90            key: &Array<Key>, iv: &Array<Iv>, aad: &[u8], clear: Option<&[u8]>, cipher: &mut [u8],
91            tag: &mut Array<Self::Tag>,
92        ) -> Result<(), Error> {
93            let aead = T::new(key);
94            if let Some(clear) = clear {
95                cipher.copy_from_slice(clear);
96            }
97            tag.copy_from_slice(
98                &aead.encrypt_in_place_detached(iv, aad, cipher).map_err(|_| Error::world(0))?,
99            );
100            Ok(())
101        }
102
103        fn decrypt(
104            key: &Array<Key>, iv: &Array<Iv>, aad: &[u8], cipher: Option<&[u8]>,
105            tag: &Array<Self::Tag>, clear: &mut [u8],
106        ) -> Result<(), Error> {
107            let aead = T::new(key);
108            if let Some(cipher) = cipher {
109                clear.copy_from_slice(cipher);
110            }
111            aead.decrypt_in_place_detached(iv, aad, clear, tag).map_err(|_| Error::world(0))
112        }
113    }
114}
wasefire_board_api/crypto/aead.rs

wasefire_board_api/crypto/
aead.rs
