165 lines
6.1 KiB
JavaScript
165 lines
6.1 KiB
JavaScript
import { pbkdf2, sha256 } from "../crypto/index.js";
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import { defineProperties, getBytes, hexlify, assertNormalize, assertPrivate, assertArgument, toUtf8Bytes } from "../utils/index.js";
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import { LangEn } from "../wordlists/lang-en.js";
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// Returns a byte with the MSB bits set
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function getUpperMask(bits) {
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return ((1 << bits) - 1) << (8 - bits) & 0xff;
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}
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// Returns a byte with the LSB bits set
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function getLowerMask(bits) {
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return ((1 << bits) - 1) & 0xff;
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}
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function mnemonicToEntropy(mnemonic, wordlist) {
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assertNormalize("NFKD");
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if (wordlist == null) {
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wordlist = LangEn.wordlist();
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}
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const words = wordlist.split(mnemonic);
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assertArgument((words.length % 3) === 0 && words.length >= 12 && words.length <= 24, "invalid mnemonic length", "mnemonic", "[ REDACTED ]");
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const entropy = new Uint8Array(Math.ceil(11 * words.length / 8));
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let offset = 0;
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for (let i = 0; i < words.length; i++) {
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let index = wordlist.getWordIndex(words[i].normalize("NFKD"));
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assertArgument(index >= 0, `invalid mnemonic word at index ${i}`, "mnemonic", "[ REDACTED ]");
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for (let bit = 0; bit < 11; bit++) {
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if (index & (1 << (10 - bit))) {
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entropy[offset >> 3] |= (1 << (7 - (offset % 8)));
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}
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offset++;
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}
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}
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const entropyBits = 32 * words.length / 3;
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const checksumBits = words.length / 3;
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const checksumMask = getUpperMask(checksumBits);
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const checksum = getBytes(sha256(entropy.slice(0, entropyBits / 8)))[0] & checksumMask;
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assertArgument(checksum === (entropy[entropy.length - 1] & checksumMask), "invalid mnemonic checksum", "mnemonic", "[ REDACTED ]");
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return hexlify(entropy.slice(0, entropyBits / 8));
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}
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function entropyToMnemonic(entropy, wordlist) {
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assertArgument((entropy.length % 4) === 0 && entropy.length >= 16 && entropy.length <= 32, "invalid entropy size", "entropy", "[ REDACTED ]");
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if (wordlist == null) {
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wordlist = LangEn.wordlist();
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}
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const indices = [0];
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let remainingBits = 11;
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for (let i = 0; i < entropy.length; i++) {
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// Consume the whole byte (with still more to go)
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if (remainingBits > 8) {
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indices[indices.length - 1] <<= 8;
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indices[indices.length - 1] |= entropy[i];
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remainingBits -= 8;
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// This byte will complete an 11-bit index
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}
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else {
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indices[indices.length - 1] <<= remainingBits;
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indices[indices.length - 1] |= entropy[i] >> (8 - remainingBits);
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// Start the next word
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indices.push(entropy[i] & getLowerMask(8 - remainingBits));
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remainingBits += 3;
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}
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}
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// Compute the checksum bits
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const checksumBits = entropy.length / 4;
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const checksum = parseInt(sha256(entropy).substring(2, 4), 16) & getUpperMask(checksumBits);
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// Shift the checksum into the word indices
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indices[indices.length - 1] <<= checksumBits;
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indices[indices.length - 1] |= (checksum >> (8 - checksumBits));
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return wordlist.join(indices.map((index) => wordlist.getWord(index)));
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}
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const _guard = {};
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/**
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* A **Mnemonic** wraps all properties required to compute [[link-bip-39]]
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* seeds and convert between phrases and entropy.
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*/
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export class Mnemonic {
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/**
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* The mnemonic phrase of 12, 15, 18, 21 or 24 words.
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*
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* Use the [[wordlist]] ``split`` method to get the individual words.
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*/
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phrase;
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/**
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* The password used for this mnemonic. If no password is used this
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* is the empty string (i.e. ``""``) as per the specification.
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*/
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password;
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/**
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* The wordlist for this mnemonic.
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*/
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wordlist;
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/**
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* The underlying entropy which the mnemonic encodes.
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*/
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entropy;
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/**
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* @private
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*/
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constructor(guard, entropy, phrase, password, wordlist) {
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if (password == null) {
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password = "";
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}
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if (wordlist == null) {
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wordlist = LangEn.wordlist();
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}
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assertPrivate(guard, _guard, "Mnemonic");
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defineProperties(this, { phrase, password, wordlist, entropy });
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}
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/**
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* Returns the seed for the mnemonic.
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*/
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computeSeed() {
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const salt = toUtf8Bytes("mnemonic" + this.password, "NFKD");
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return pbkdf2(toUtf8Bytes(this.phrase, "NFKD"), salt, 2048, 64, "sha512");
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}
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/**
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* Creates a new Mnemonic for the %%phrase%%.
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*
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* The default %%password%% is the empty string and the default
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* wordlist is the [English wordlists](LangEn).
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*/
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static fromPhrase(phrase, password, wordlist) {
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// Normalize the case and space; throws if invalid
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const entropy = mnemonicToEntropy(phrase, wordlist);
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phrase = entropyToMnemonic(getBytes(entropy), wordlist);
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return new Mnemonic(_guard, entropy, phrase, password, wordlist);
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}
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/**
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* Create a new **Mnemonic** from the %%entropy%%.
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*
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* The default %%password%% is the empty string and the default
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* wordlist is the [English wordlists](LangEn).
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*/
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static fromEntropy(_entropy, password, wordlist) {
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const entropy = getBytes(_entropy, "entropy");
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const phrase = entropyToMnemonic(entropy, wordlist);
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return new Mnemonic(_guard, hexlify(entropy), phrase, password, wordlist);
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}
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/**
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* Returns the phrase for %%mnemonic%%.
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*/
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static entropyToPhrase(_entropy, wordlist) {
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const entropy = getBytes(_entropy, "entropy");
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return entropyToMnemonic(entropy, wordlist);
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}
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/**
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* Returns the entropy for %%phrase%%.
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*/
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static phraseToEntropy(phrase, wordlist) {
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return mnemonicToEntropy(phrase, wordlist);
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}
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/**
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* Returns true if %%phrase%% is a valid [[link-bip-39]] phrase.
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*
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* This checks all the provided words belong to the %%wordlist%%,
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* that the length is valid and the checksum is correct.
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*/
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static isValidMnemonic(phrase, wordlist) {
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try {
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mnemonicToEntropy(phrase, wordlist);
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return true;
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}
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catch (error) { }
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return false;
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}
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}
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//# sourceMappingURL=mnemonic.js.map
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