ethers.js/lib.esm/wallet/mnemonic.js
2022-12-02 21:27:06 -05:00

165 lines
6.1 KiB
JavaScript

import { pbkdf2, sha256 } from "../crypto/index.js";
import { defineProperties, getBytes, hexlify, assertNormalize, assertPrivate, assertArgument, toUtf8Bytes } from "../utils/index.js";
import { LangEn } from "../wordlists/lang-en.js";
// Returns a byte with the MSB bits set
function getUpperMask(bits) {
return ((1 << bits) - 1) << (8 - bits) & 0xff;
}
// Returns a byte with the LSB bits set
function getLowerMask(bits) {
return ((1 << bits) - 1) & 0xff;
}
function mnemonicToEntropy(mnemonic, wordlist) {
assertNormalize("NFKD");
if (wordlist == null) {
wordlist = LangEn.wordlist();
}
const words = wordlist.split(mnemonic);
assertArgument((words.length % 3) === 0 && words.length >= 12 && words.length <= 24, "invalid mnemonic length", "mnemonic", "[ REDACTED ]");
const entropy = new Uint8Array(Math.ceil(11 * words.length / 8));
let offset = 0;
for (let i = 0; i < words.length; i++) {
let index = wordlist.getWordIndex(words[i].normalize("NFKD"));
assertArgument(index >= 0, `invalid mnemonic word at index ${i}`, "mnemonic", "[ REDACTED ]");
for (let bit = 0; bit < 11; bit++) {
if (index & (1 << (10 - bit))) {
entropy[offset >> 3] |= (1 << (7 - (offset % 8)));
}
offset++;
}
}
const entropyBits = 32 * words.length / 3;
const checksumBits = words.length / 3;
const checksumMask = getUpperMask(checksumBits);
const checksum = getBytes(sha256(entropy.slice(0, entropyBits / 8)))[0] & checksumMask;
assertArgument(checksum === (entropy[entropy.length - 1] & checksumMask), "invalid mnemonic checksum", "mnemonic", "[ REDACTED ]");
return hexlify(entropy.slice(0, entropyBits / 8));
}
function entropyToMnemonic(entropy, wordlist) {
assertArgument((entropy.length % 4) === 0 && entropy.length >= 16 && entropy.length <= 32, "invalid entropy size", "entropy", "[ REDACTED ]");
if (wordlist == null) {
wordlist = LangEn.wordlist();
}
const indices = [0];
let remainingBits = 11;
for (let i = 0; i < entropy.length; i++) {
// Consume the whole byte (with still more to go)
if (remainingBits > 8) {
indices[indices.length - 1] <<= 8;
indices[indices.length - 1] |= entropy[i];
remainingBits -= 8;
// This byte will complete an 11-bit index
}
else {
indices[indices.length - 1] <<= remainingBits;
indices[indices.length - 1] |= entropy[i] >> (8 - remainingBits);
// Start the next word
indices.push(entropy[i] & getLowerMask(8 - remainingBits));
remainingBits += 3;
}
}
// Compute the checksum bits
const checksumBits = entropy.length / 4;
const checksum = parseInt(sha256(entropy).substring(2, 4), 16) & getUpperMask(checksumBits);
// Shift the checksum into the word indices
indices[indices.length - 1] <<= checksumBits;
indices[indices.length - 1] |= (checksum >> (8 - checksumBits));
return wordlist.join(indices.map((index) => wordlist.getWord(index)));
}
const _guard = {};
/**
* A **Mnemonic** wraps all properties required to compute [[link-bip39]]
* seeds and convert between phrases and entropy.
*/
export class Mnemonic {
/**
* The mnemonic phrase of 12, 15, 18, 21 or 24 words.
*
* Use the [[wordlist]] ``split`` method to get the individual words.
*/
phrase;
/**
* The password used for this mnemonic. If no password is used this
* is the empty string (i.e. ``""``) as per the specification.
*/
password;
/**
* The wordlist for this mnemonic.
*/
wordlist;
/**
* The underlying entropy which the mnemonic encodes.
*/
entropy;
/**
* @private
*/
constructor(guard, entropy, phrase, password, wordlist) {
if (password == null) {
password = "";
}
if (wordlist == null) {
wordlist = LangEn.wordlist();
}
assertPrivate(guard, _guard, "Mnemonic");
defineProperties(this, { phrase, password, wordlist, entropy });
}
/**
* Returns the seed for the mnemonic.
*/
computeSeed() {
const salt = toUtf8Bytes("mnemonic" + this.password, "NFKD");
return pbkdf2(toUtf8Bytes(this.phrase, "NFKD"), salt, 2048, 64, "sha512");
}
/**
* Creates a new Mnemonic for the %%phrase%%.
*
* The default %%password%% is the empty string and the default
* wordlist is the [English wordlists](LangEn).
*/
static fromPhrase(phrase, password, wordlist) {
// Normalize the case and space; throws if invalid
const entropy = mnemonicToEntropy(phrase, wordlist);
phrase = entropyToMnemonic(getBytes(entropy), wordlist);
return new Mnemonic(_guard, entropy, phrase, password, wordlist);
}
/**
* Create a new **Mnemonic** from the %%entropy%%.
*
* The default %%password%% is the empty string and the default
* wordlist is the [English wordlists](LangEn).
*/
static fromEntropy(_entropy, password, wordlist) {
const entropy = getBytes(_entropy, "entropy");
const phrase = entropyToMnemonic(entropy, wordlist);
return new Mnemonic(_guard, hexlify(entropy), phrase, password, wordlist);
}
/**
* Returns the phrase for %%mnemonic%%.
*/
static entropyToPhrase(_entropy, wordlist) {
const entropy = getBytes(_entropy, "entropy");
return entropyToMnemonic(entropy, wordlist);
}
/**
* Returns the entropy for %%phrase%%.
*/
static phraseToEntropy(phrase, wordlist) {
return mnemonicToEntropy(phrase, wordlist);
}
/**
* Returns true if %%phrase%% is a valid [[link-bip39]] phrase.
*
* This checks all the provided words belong to the %%wordlist%%,
* that the length is valid and the checksum is correct.
*/
static isValidMnemonic(phrase, wordlist) {
try {
mnemonicToEntropy(phrase, wordlist);
return true;
}
catch (error) { }
return false;
}
}
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