135 lines
No EOL
5.9 KiB
JavaScript
135 lines
No EOL
5.9 KiB
JavaScript
/**
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* PBKDF (RFC 2898). Can be used to create a key from password and salt.
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* @module
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*/
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import { hmac } from "./hmac.js";
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// prettier-ignore
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import { ahash, anumber, asyncLoop, checkOpts, clean, createView, kdfInputToBytes } from "./utils.js";
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// Common start and end for sync/async functions
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function pbkdf2Init(hash, _password, _salt, _opts) {
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ahash(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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anumber(c, 'c');
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anumber(dkLen, 'dkLen');
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anumber(asyncTick, 'asyncTick');
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if (c < 1)
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throw new Error('iterations (c) must be >= 1');
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// RFC 8018 §5.2 defines `dkLen` as "a positive integer".
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if (dkLen < 1)
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throw new Error('"dkLen" must be >= 1');
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// RFC 8018 §5.2 step 1 requires rejecting oversize `dkLen`
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// before allocating the destination buffer.
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if (dkLen > (2 ** 32 - 1) * hash.outputLen)
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throw new Error('derived key too long');
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const password = kdfInputToBytes(_password, 'password');
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const salt = kdfInputToBytes(_salt, '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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// Cache PRF(P, S || ...) prefix state so each block only appends INT_32_BE(i).
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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(PRF, PRFSalt, DK, prfW, u) {
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// Shared sync/async cleanup point: wipe transient PRF state
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// while preserving the derived key buffer.
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PRF.destroy();
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PRFSalt.destroy();
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if (prfW)
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prfW.destroy();
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clean(u);
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return DK;
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}
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/**
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* PBKDF2-HMAC: RFC 8018 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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* JS string inputs are UTF-8 encoded first
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* @param salt - cryptographic salt; JS string inputs are UTF-8 encoded first
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* @param opts - PBKDF2 work factor and output settings. `dkLen`, if provided,
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* must be `>= 1` per RFC 8018 §5.2. See {@link Pbkdf2Opt}.
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* @returns Derived key bytes.
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* @throws If the PBKDF2 iteration count or derived-key settings are invalid. {@link Error}
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* @example
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* PBKDF2-HMAC: RFC 2898 key derivation function.
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* ```ts
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* import { pbkdf2 } from '@noble/hashes/pbkdf2.js';
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* import { sha256 } from '@noble/hashes/sha2.js';
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* const key = pbkdf2(sha256, 'password', 'salt', { dkLen: 32, c: Math.pow(2, 18) });
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* ```
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*/
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export function pbkdf2(hash, password, salt, opts) {
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const { c, dkLen, DK, PRF, PRFSalt } = pbkdf2Init(hash, password, salt, opts);
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let prfW; // 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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// The last Ti view can be shorter than hLen, which applies
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// RFC 8018 §5.2 step 4's T_l<0..r-1> truncation without extra copies.
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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++)
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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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/**
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* PBKDF2-HMAC: RFC 8018 key derivation function. Async version.
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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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* JS string inputs are UTF-8 encoded first
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* @param salt - cryptographic salt; JS string inputs are UTF-8 encoded first
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* @param opts - PBKDF2 work factor and output settings. `dkLen`, if provided,
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* must be `>= 1` per RFC 8018 §5.2. `asyncTick` is only a local
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* scheduler-yield knob for this JS wrapper, not part of RFC 8018.
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* See {@link Pbkdf2Opt}.
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* @returns Promise resolving to derived key bytes.
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* @throws If the PBKDF2 iteration count or derived-key settings are invalid. {@link Error}
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* @example
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* PBKDF2-HMAC: RFC 2898 key derivation function.
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* ```ts
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* import { pbkdf2Async } from '@noble/hashes/pbkdf2.js';
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* import { sha256 } from '@noble/hashes/sha2.js';
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* const key = await pbkdf2Async(sha256, 'password', 'salt', { dkLen: 32, c: 500_000 });
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* ```
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*/
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export async function pbkdf2Async(hash, password, salt, opts) {
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const { c, dkLen, asyncTick, DK, PRF, PRFSalt } = pbkdf2Init(hash, password, salt, opts);
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let prfW; // 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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// The last Ti view can be shorter than hLen, which applies
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// RFC 8018 §5.2 step 4's T_l<0..r-1> truncation without extra copies.
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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, () => {
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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++)
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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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//# sourceMappingURL=pbkdf2.js.map
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