core_crypto_keystore/
hash.rs

1use std::fmt;
2
3use sha2::{Digest, Sha256};
4
5use crate::{
6    CryptoKeystoreResult,
7    traits::{KeyType, OwnedKeyType},
8};
9
10/// Used to calculate ID hashes for some MlsEntities' SQLite tables.
11pub(crate) fn sha256(data: &[u8]) -> String {
12    Sha256Hash::hash_from(data).to_string()
13}
14
15/// A Sha256 hash.
16///
17/// Certain entities use this kind of hash as a key. It's a small value which lives on the stack,
18/// as opposed to the longer, heap-allocated values which it replaces.
19///
20/// This type enables this use case with the new entity traits.
21#[derive(
22    Debug,
23    Default,
24    Clone,
25    Copy,
26    PartialEq,
27    Eq,
28    PartialOrd,
29    Ord,
30    Hash,
31    derive_more::Deref,
32    derive_more::AsRef,
33    derive_more::From,
34    derive_more::Into,
35    serde::Serialize,
36    serde::Deserialize,
37)]
38#[as_ref(forward)]
39pub struct Sha256Hash([u8; 32]);
40
41impl Sha256Hash {
42    /// Create an instance by hashing a single input value.
43    pub fn hash_from(input: impl AsRef<[u8]>) -> Self {
44        let mut hasher = Sha256::new();
45        hasher.update(input);
46        Self(hasher.finalize().into())
47    }
48
49    /// Convert an existing hash into an instance of this type.
50    ///
51    /// Only basic length checking is performed!
52    pub fn from_existing_hash(hash: impl AsRef<[u8]>) -> CryptoKeystoreResult<Self> {
53        let array = hash.as_ref().try_into()?;
54        Ok(Self(array))
55    }
56}
57
58impl fmt::Display for Sha256Hash {
59    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
60        let mut hex_bytes = [0; 64];
61        hex::encode_to_slice(self.0, hex_bytes.as_mut_slice())
62            .expect("infallible given inputs and outputs of fixed correct length");
63        let hex_str = str::from_utf8(&hex_bytes).expect("hex crate always produces valid utf8 data");
64        write!(f, "{hex_str}")
65    }
66}
67
68impl KeyType for Sha256Hash {
69    fn bytes(&self) -> std::borrow::Cow<'_, [u8]> {
70        (&self.0).into()
71    }
72}
73
74impl OwnedKeyType for Sha256Hash {
75    fn from_bytes(bytes: &[u8]) -> Option<Self> {
76        bytes.try_into().ok().map(Self)
77    }
78}
79
80impl rusqlite::ToSql for Sha256Hash {
81    fn to_sql(&self) -> rusqlite::Result<rusqlite::types::ToSqlOutput<'_>> {
82        self.as_ref().to_sql()
83    }
84}
core_crypto_keystore/hash.rs

core_crypto_keystore/
hash.rs
