wasi_crypto/symmetric/
tag.rs

1use subtle::ConstantTimeEq;
2use zeroize::Zeroize;
3
4use super::*;
5use crate::CryptoCtx;
6
7#[derive(Debug, Clone, Eq)]
8pub struct SymmetricTag {
9    alg: SymmetricAlgorithm,
10    raw: Vec<u8>,
11}
12
13impl PartialEq for SymmetricTag {
14    fn eq(&self, other: &Self) -> bool {
15        self.alg == other.alg && self.raw.ct_eq(&other.raw).unwrap_u8() == 1
16    }
17}
18
19impl Drop for SymmetricTag {
20    fn drop(&mut self) {
21        self.raw.zeroize();
22    }
23}
24
25impl SymmetricTag {
26    pub fn new(alg: SymmetricAlgorithm, raw: Vec<u8>) -> Self {
27        SymmetricTag { alg, raw }
28    }
29
30    pub fn verify(&self, expected_raw: &[u8]) -> Result<(), CryptoError> {
31        ensure!(
32            self.raw.ct_eq(expected_raw).unwrap_u8() == 1,
33            CryptoError::InvalidTag
34        );
35        Ok(())
36    }
37}
38
39impl AsRef<[u8]> for SymmetricTag {
40    fn as_ref(&self) -> &[u8] {
41        &self.raw
42    }
43}
44
45impl CryptoCtx {
46    pub fn symmetric_tag_len(&self, symmetric_tag_handle: Handle) -> Result<usize, CryptoError> {
47        let symmetric_tag = self.handles.symmetric_tag.get(symmetric_tag_handle)?;
48        Ok(symmetric_tag.as_ref().len())
49    }
50
51    pub fn symmetric_tag_pull(
52        &self,
53        symmetric_tag_handle: Handle,
54        buf: &mut [u8],
55    ) -> Result<usize, CryptoError> {
56        let symmetric_tag = self.handles.symmetric_tag.get(symmetric_tag_handle)?;
57        let raw = symmetric_tag.as_ref();
58        let raw_len = raw.len();
59        let buf_len = buf.len();
60        ensure!(raw_len <= buf_len, CryptoError::Overflow);
61        buf[..raw_len].copy_from_slice(raw);
62        self.handles.symmetric_tag.close(symmetric_tag_handle)?;
63        Ok(raw_len)
64    }
65
66    pub fn symmetric_tag_verify(
67        &self,
68        symmetric_tag_handle: Handle,
69        expected_raw: &[u8],
70    ) -> Result<(), CryptoError> {
71        let symmetric_tag = self.handles.symmetric_tag.get(symmetric_tag_handle)?;
72        symmetric_tag.verify(expected_raw)
73    }
74
75    pub fn symmetric_tag_close(&self, symmetric_tag_handle: Handle) -> Result<(), CryptoError> {
76        self.handles.symmetric_tag.close(symmetric_tag_handle)
77    }
78}
wasi_crypto/symmetric/tag.rs

wasi_crypto/symmetric/
tag.rs
