embedded_wg_display/util/
hasher.rs

1//! SHA-256 hashing with hardware SHA peripheral.
2use esp_hal::{
3    peripherals::SHA,
4    sha::{Sha, Sha256},
5};
6use nb::block;
7
8/// Wraps the ESP32 hardware SHA peripheral for SHA-256 computation.
9pub struct Hasher<'d> {
10    sha: Sha<'d>,
11}
12
13impl<'d> Hasher<'d> {
14    /// Creates a new [`Hasher`] from the `SHA` peripheral.
15    pub fn new(sha_peripherals: SHA<'d>) -> Self {
16        Self {
17            sha: Sha::new(sha_peripherals),
18        }
19    }
20
21    // create a 14 bit hash for the wasm binary nvs storage
22    // based on the example from https://docs.rs/esp32-hal/latest/esp32_hal/sha/index.html
23    pub fn hash(&mut self, input: &str) -> [u8; 14] {
24        let mut hasher = self.sha.start::<Sha256>();
25        let mut remaining = input.as_bytes();
26        let mut output = [0u8; 14];
27
28        while !remaining.is_empty() {
29            // update() returns the not-yet-consumed tail until the HW block is processed.
30            remaining = block!(hasher.update(remaining)).unwrap();
31        }
32
33        // Provide a shorter output buffer to get a truncated digest.
34        block!(hasher.finish(output.as_mut_slice())).unwrap();
35        output
36    }
37}
embedded_wg_display/util/hasher.rs

embedded_wg_display/util/
hasher.rs
