antelope-ecc/mnemonic_create.js

A universal JavaScript ECC digital signature and key utility package for Antelope based blockchains.

import sha256 from "isomorphic-secp256k1-js/sha256.js";
import words from "./internal/mnemonic-words.js";
import random_bytes from "./internal/random_bytes.js";
/**
 * Generates a BIP39 24-word mnemonic representing a 32-byte private key.
 *
 * @param bytes - 32 bytes of data, typically a private key.
 * @returns A Promise that resolves to an array of strings representing the BIP39 mnemonic.
 *
 * @example
 * ```ts
 * import createMnemonic from "antelope-ecc/mnemonic-create.js";
 *
 * const bytes = crypto.randomBytes(32); // The private key
 * createMnemonic(bytes).then(console.log); // BIP39 words.
 * ```
 * The logged output will be an array like: `['abandon', 'busy', …]`.
 */
export default async function createMnemonic(bytes) {
    if (!bytes)
        bytes = await random_bytes(32);
    let bitLen = 8 * bytes.length;
    let sumBitLen = bitLen / 32;
    bytes = new Uint8Array(bytes);
    let hashAb = await sha256(bytes);
    let hashBuf = new Uint8Array(hashAb);
    let bits = "";
    bytes.forEach((n) => {
        let b = n.toString(2).padStart(8, "0");
        bits += b;
    });
    let checkByte = hashBuf[0];
    let checkBits = checkByte.toString(2);
    checkBits = checkBits.padStart(8, "0");
    let checksum = checkBits.slice(0, sumBitLen);
    bits += checksum;
    const seed = [];
    for (let bit = 0; bit < bitLen + sumBitLen; bit += 11) {
        // 11-bit integer (0-2047)
        let i = parseInt(bits.slice(bit, bit + 11).padStart(8, "0"), 2);
        seed.push(i);
    }
    return seed.map((i) => words[i]).join(" ");
}