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// -*- coding: utf-8 -*-
//
// disktest - Storage tester
//
// Copyright 2020-2024 Michael Büsch <m@bues.ch>
//
// Licensed under the Apache License version 2.0
// or the MIT license, at your option.
// SPDX-License-Identifier: Apache-2.0 OR MIT
//
use ring::{digest, pbkdf2};
const ITERATIONS: u32 = 50000;
const DK_SIZE: usize = 256 / 8;
/// Generate a bad salt substitution from the key.
fn derive_salt(key: &[u8]) -> [u8; 512 / 8] {
// Generate the salt from the key.
// That's not a great salt, but good enough for our purposes.
let mut salt_hash = digest::Context::new(&digest::SHA512);
salt_hash.update(b"disktest salt");
salt_hash.update(key);
salt_hash.finish().as_ref().try_into().unwrap()
}
/// Key derivation function for the user supplied seed.
pub fn kdf(seed: &[u8], thread_id: u32, round_id: u64) -> Vec<u8> {
// For the first round the key is:
// SEED | THREAD_ID_le32
// For all subsequent rounds the key is:
// SEED | THREAD_ID_le32 | "R" | ROUND_ID_le64
let mut key = seed.to_vec();
key.extend_from_slice(&thread_id.to_le_bytes());
if round_id > 0 {
key.extend_from_slice(b"R");
key.extend_from_slice(&round_id.to_le_bytes());
}
// Calculated the DK (derived key).
let mut dk = vec![0; DK_SIZE];
pbkdf2::derive(
pbkdf2::PBKDF2_HMAC_SHA512,
ITERATIONS.try_into().unwrap(),
&derive_salt(&key),
&key,
&mut dk,
);
dk
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_salt() {
assert_eq!(
derive_salt(&[1, 2, 3]).to_vec(),
derive_salt(&[1, 2, 3]).to_vec()
);
assert_ne!(
derive_salt(&[1, 2, 3]).to_vec(),
derive_salt(&[1, 2, 4]).to_vec()
);
}
#[test]
fn test_kdf() {
// round 0
assert_eq!(
kdf(&[1, 2, 3], 42, 0),
[
126, 166, 175, 110, 112, 203, 204, 118, 71, 125, 227, 115, 65, 242, 193, 117, 229,
246, 164, 226, 239, 88, 119, 226, 21, 98, 166, 137, 232, 151, 243, 154
]
);
assert_eq!(
kdf(&[1, 2, 4], 42, 0),
[
141, 91, 148, 215, 223, 193, 155, 52, 32, 216, 66, 86, 110, 114, 5, 10, 39, 253,
243, 146, 37, 243, 25, 238, 218, 100, 179, 204, 12, 150, 13, 102
]
);
assert_eq!(
kdf(&[1, 2, 3], 43, 0),
[
8, 206, 134, 103, 131, 239, 126, 159, 222, 12, 74, 197, 28, 44, 237, 166, 152, 102,
63, 199, 93, 82, 199, 62, 97, 178, 240, 244, 24, 148, 242, 209
]
);
// round 1
assert_eq!(
kdf(&[1, 2, 3], 42, 1),
[
115, 110, 74, 205, 25, 140, 57, 127, 9, 198, 152, 123, 116, 139, 243, 181, 85, 239,
95, 176, 75, 182, 136, 85, 150, 194, 224, 96, 136, 237, 14, 84
]
);
// round u64::MAX - 1
assert_eq!(
kdf(&[1, 2, 3], 42, u64::MAX - 1),
[
212, 130, 54, 50, 137, 221, 173, 20, 116, 196, 191, 41, 232, 6, 73, 37, 190, 154,
152, 135, 207, 142, 166, 44, 254, 104, 52, 127, 205, 195, 122, 231
]
);
}
}
// vim: ts=4 sw=4 expandtab
|
