98 lines
3.6 KiB
Plaintext
98 lines
3.6 KiB
Plaintext
import assert from './_assert.js';
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import { hmac } from './hmac.js';
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import { Hash, CHash, Input, createView, toBytes, checkOpts, asyncLoop } from './utils.js';
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// PBKDF (RFC 2898)
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export type Pbkdf2Opt = {
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c: number; // Iterations
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dkLen?: number; // Desired key length in bytes (Intended output length in octets of the derived key
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asyncTick?: number; // Maximum time in ms for which async function can block execution
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};
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// Common prologue and epilogue for sync/async functions
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function pbkdf2Init(hash: CHash, _password: Input, _salt: Input, _opts: Pbkdf2Opt) {
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assert.hash(hash);
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const opts = checkOpts({ dkLen: 32, asyncTick: 10 }, _opts);
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const { c, dkLen, asyncTick } = opts;
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assert.number(c);
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assert.number(dkLen);
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assert.number(asyncTick);
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if (c < 1) throw new Error('PBKDF2: iterations (c) should be >= 1');
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const password = toBytes(_password);
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const salt = toBytes(_salt);
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// DK = PBKDF2(PRF, Password, Salt, c, dkLen);
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const DK = new Uint8Array(dkLen);
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// U1 = PRF(Password, Salt + INT_32_BE(i))
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const PRF = hmac.create(hash, password);
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const PRFSalt = PRF._cloneInto().update(salt);
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return { c, dkLen, asyncTick, DK, PRF, PRFSalt };
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}
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function pbkdf2Output<T extends Hash<T>>(
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PRF: Hash<T>,
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PRFSalt: Hash<T>,
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DK: Uint8Array,
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prfW: Hash<T>,
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u: Uint8Array
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) {
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PRF.destroy();
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PRFSalt.destroy();
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if (prfW) prfW.destroy();
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u.fill(0);
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return DK;
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}
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/**
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* PBKDF2-HMAC: RFC 2898 key derivation function
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* @param hash - hash function that would be used e.g. sha256
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* @param password - password from which a derived key is generated
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* @param salt - cryptographic salt
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* @param opts - {c, dkLen} where c is work factor and dkLen is output message size
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*/
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export function pbkdf2(hash: CHash, password: Input, salt: Input, opts: Pbkdf2Opt) {
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const { c, dkLen, DK, PRF, PRFSalt } = pbkdf2Init(hash, password, salt, opts);
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let prfW: any; // Working copy
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const arr = new Uint8Array(4);
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const view = createView(arr);
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const u = new Uint8Array(PRF.outputLen);
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// DK = T1 + T2 + ⋯ + Tdklen/hlen
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for (let ti = 1, pos = 0; pos < dkLen; ti++, pos += PRF.outputLen) {
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// Ti = F(Password, Salt, c, i)
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const Ti = DK.subarray(pos, pos + PRF.outputLen);
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view.setInt32(0, ti, false);
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// F(Password, Salt, c, i) = U1 ^ U2 ^ ⋯ ^ Uc
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// U1 = PRF(Password, Salt + INT_32_BE(i))
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(prfW = PRFSalt._cloneInto(prfW)).update(arr).digestInto(u);
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Ti.set(u.subarray(0, Ti.length));
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for (let ui = 1; ui < c; ui++) {
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// Uc = PRF(Password, Uc−1)
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PRF._cloneInto(prfW).update(u).digestInto(u);
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for (let i = 0; i < Ti.length; i++) Ti[i] ^= u[i];
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}
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}
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return pbkdf2Output(PRF, PRFSalt, DK, prfW, u);
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}
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export async function pbkdf2Async(hash: CHash, password: Input, salt: Input, opts: Pbkdf2Opt) {
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const { c, dkLen, asyncTick, DK, PRF, PRFSalt } = pbkdf2Init(hash, password, salt, opts);
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let prfW: any; // Working copy
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const arr = new Uint8Array(4);
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const view = createView(arr);
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const u = new Uint8Array(PRF.outputLen);
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// DK = T1 + T2 + ⋯ + Tdklen/hlen
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for (let ti = 1, pos = 0; pos < dkLen; ti++, pos += PRF.outputLen) {
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// Ti = F(Password, Salt, c, i)
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const Ti = DK.subarray(pos, pos + PRF.outputLen);
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view.setInt32(0, ti, false);
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// F(Password, Salt, c, i) = U1 ^ U2 ^ ⋯ ^ Uc
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// U1 = PRF(Password, Salt + INT_32_BE(i))
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(prfW = PRFSalt._cloneInto(prfW)).update(arr).digestInto(u);
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Ti.set(u.subarray(0, Ti.length));
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await asyncLoop(c - 1, asyncTick, (i) => {
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// Uc = PRF(Password, Uc−1)
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PRF._cloneInto(prfW).update(u).digestInto(u);
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for (let i = 0; i < Ti.length; i++) Ti[i] ^= u[i];
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});
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}
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return pbkdf2Output(PRF, PRFSalt, DK, prfW, u);
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}
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