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2025-04-19 15:38:48 +08:00
import { hash as assertHash, number as assertNumber } from './_assert.js';
import { hmac } from './hmac.js';
import { createView, toBytes, checkOpts, asyncLoop } from './utils.js';
// Common prologue and epilogue for sync/async functions
function pbkdf2Init(hash, _password, _salt, _opts) {
assertHash(hash);
const opts = checkOpts({ dkLen: 32, asyncTick: 10 }, _opts);
const { c, dkLen, asyncTick } = opts;
assertNumber(c);
assertNumber(dkLen);
assertNumber(asyncTick);
if (c < 1)
throw new Error('PBKDF2: iterations (c) should be >= 1');
const password = toBytes(_password);
const salt = toBytes(_salt);
// DK = PBKDF2(PRF, Password, Salt, c, dkLen);
const DK = new Uint8Array(dkLen);
// U1 = PRF(Password, Salt + INT_32_BE(i))
const PRF = hmac.create(hash, password);
const PRFSalt = PRF._cloneInto().update(salt);
return { c, dkLen, asyncTick, DK, PRF, PRFSalt };
}
function pbkdf2Output(PRF, PRFSalt, DK, prfW, u) {
PRF.destroy();
PRFSalt.destroy();
if (prfW)
prfW.destroy();
u.fill(0);
return DK;
}
/**
* PBKDF2-HMAC: RFC 2898 key derivation function
* @param hash - hash function that would be used e.g. sha256
* @param password - password from which a derived key is generated
* @param salt - cryptographic salt
* @param opts - {c, dkLen} where c is work factor and dkLen is output message size
*/
export function pbkdf2(hash, password, salt, opts) {
const { c, dkLen, DK, PRF, PRFSalt } = pbkdf2Init(hash, password, salt, opts);
let prfW; // Working copy
const arr = new Uint8Array(4);
const view = createView(arr);
const u = new Uint8Array(PRF.outputLen);
// DK = T1 + T2 + ⋯ + Tdklen/hlen
for (let ti = 1, pos = 0; pos < dkLen; ti++, pos += PRF.outputLen) {
// Ti = F(Password, Salt, c, i)
const Ti = DK.subarray(pos, pos + PRF.outputLen);
view.setInt32(0, ti, false);
// F(Password, Salt, c, i) = U1 ^ U2 ^ ⋯ ^ Uc
// U1 = PRF(Password, Salt + INT_32_BE(i))
(prfW = PRFSalt._cloneInto(prfW)).update(arr).digestInto(u);
Ti.set(u.subarray(0, Ti.length));
for (let ui = 1; ui < c; ui++) {
// Uc = PRF(Password, Uc1)
PRF._cloneInto(prfW).update(u).digestInto(u);
for (let i = 0; i < Ti.length; i++)
Ti[i] ^= u[i];
}
}
return pbkdf2Output(PRF, PRFSalt, DK, prfW, u);
}
export async function pbkdf2Async(hash, password, salt, opts) {
const { c, dkLen, asyncTick, DK, PRF, PRFSalt } = pbkdf2Init(hash, password, salt, opts);
let prfW; // Working copy
const arr = new Uint8Array(4);
const view = createView(arr);
const u = new Uint8Array(PRF.outputLen);
// DK = T1 + T2 + ⋯ + Tdklen/hlen
for (let ti = 1, pos = 0; pos < dkLen; ti++, pos += PRF.outputLen) {
// Ti = F(Password, Salt, c, i)
const Ti = DK.subarray(pos, pos + PRF.outputLen);
view.setInt32(0, ti, false);
// F(Password, Salt, c, i) = U1 ^ U2 ^ ⋯ ^ Uc
// U1 = PRF(Password, Salt + INT_32_BE(i))
(prfW = PRFSalt._cloneInto(prfW)).update(arr).digestInto(u);
Ti.set(u.subarray(0, Ti.length));
await asyncLoop(c - 1, asyncTick, () => {
// Uc = PRF(Password, Uc1)
PRF._cloneInto(prfW).update(u).digestInto(u);
for (let i = 0; i < Ti.length; i++)
Ti[i] ^= u[i];
});
}
return pbkdf2Output(PRF, PRFSalt, DK, prfW, u);
}
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