Function compute_hmac

nodedb-cluster/src/rpc_codec/mac.rs:90–98

Compute HMAC-SHA256 over `data` with `key`. Length is fixed at [`MAC_LEN`].

(key: &MacKey, data: &[u8])

/// Compute HMAC-SHA256 over `data` with `key`. Length is fixed at
/// [`MAC_LEN`].
pub fn compute_hmac(key: &MacKey, data: &[u8]) -> [u8; MAC_LEN] {
    let mut mac = <Hmac<Sha256> as Mac>::new_from_slice(key.as_bytes())
        .expect("HMAC-SHA256 accepts any key length");
    mac.update(data);
    let out = mac.finalize().into_bytes();
    let mut tag = [0u8; MAC_LEN];
    tag.copy_from_slice(&out);
    tag
}

/// Constant-time verify `tag` against HMAC-SHA256 over `data` with `key`.
/// Returns `Err` on mismatch.