wallet-core/src/crypto/primitives/kdf.ts

93 lines
2.5 KiB
TypeScript

/*
This file is part of GNU Taler
(C) 2019 GNUnet e.V.
GNU Taler is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
import * as nacl from "./nacl-fast";
import { sha256 } from "./sha256";
export function sha512(data: Uint8Array): Uint8Array {
return nacl.hash(data);
}
export function hmac(
digest: (d: Uint8Array) => Uint8Array,
blockSize: number,
key: Uint8Array,
message: Uint8Array,
): Uint8Array {
if (key.byteLength > blockSize) {
key = digest(key);
}
if (key.byteLength < blockSize) {
const k = key;
key = new Uint8Array(blockSize);
key.set(k, 0);
}
const okp = new Uint8Array(blockSize);
const ikp = new Uint8Array(blockSize);
for (let i = 0; i < blockSize; i++) {
ikp[i] = key[i] ^ 0x36;
okp[i] = key[i] ^ 0x5c;
}
const b1 = new Uint8Array(blockSize + message.byteLength);
b1.set(ikp, 0);
b1.set(message, blockSize);
const h0 = digest(b1);
const b2 = new Uint8Array(blockSize + h0.length);
b2.set(okp, 0);
b2.set(h0, blockSize);
return digest(b2);
}
export function hmacSha512(key: Uint8Array, message: Uint8Array) {
return hmac(sha512, 128, key, message);
}
export function hmacSha256(key: Uint8Array, message: Uint8Array) {
return hmac(sha256, 64, key, message);
}
export function kdf(
outputLength: number,
ikm: Uint8Array,
salt: Uint8Array,
info: Uint8Array,
): Uint8Array {
// extract
const prk = hmacSha512(salt, ikm);
// expand
const N = Math.ceil(outputLength / 32);
const output = new Uint8Array(N * 32);
for (let i = 0; i < N; i++) {
let buf;
if (i == 0) {
buf = new Uint8Array(info.byteLength + 1);
buf.set(info, 0);
} else {
buf = new Uint8Array(info.byteLength + 1 + 32);
for (let j = 0; j < 32; j++) {
buf[j] = output[(i - 1) * 32 + j];
}
buf.set(info, 32);
}
buf[buf.length - 1] = i + 1;
const chunk = hmacSha256(prk, buf);
output.set(chunk, i * 32);
}
return output.slice(0, outputLength);
}