otp-io/dist/totp.mjs

🕖 Typed library to work 2fa via Google Authenticator/Time-based TOTP/Hmac-based HOTP

import {HmacAlgorithm}from'./crypto/hmac.mjs';import {hotp}from'./hotp.mjs';import {SecretKey}from'./key.mjs';import {getDefaultTOTPOptions}from'./totp.options.mjs';const keyLengths = new Map([
    [HmacAlgorithm.SHA1, 20],
    [HmacAlgorithm.SHA256, 32],
    [HmacAlgorithm.SHA512, 64]
]);
/**
 *
 *
 * @param {Uint8Array} buffer
 * @param {number} length
 * @return {Uint8Array}
 */
function pad(buffer, length) {
    const factor = Math.ceil(length / buffer.length);
    const double = new Uint8Array(buffer.length * factor);
    for (let index = 0; index < factor; index++) {
        double.set(buffer, buffer.length * index);
    }
    return double.slice(0, length);
}
/**
 * Generates TOTP code from secret key and options
 *
 * @export
 * @param {Hmac} hmac
 * @param {TOTPOptions} options
 * @return {Promise<string>}
 * @throws {Error} if HMAC algorithm is invalid. Use {@link HmacAlgorithm} to avoid this
 */
async function totp(hmac, options) {
    const merged = Object.assign(Object.assign({}, getDefaultTOTPOptions()), options);
    const counter = Math.floor(merged.now.getTime() / 1000 / merged.stepSeconds);
    let bytes = new Uint8Array(options.secret.bytes);
    if (merged.pad) {
        const length = keyLengths.get(merged.algorithm);
        if (length === undefined) {
            throw new Error(`Invalid hmac algorithm: "${merged.algorithm}"`);
        }
        if (bytes.length < length) {
            bytes = pad(bytes, length);
        }
    }
    return await hotp(hmac, {
        secret: new SecretKey(bytes),
        algorithm: merged.algorithm,
        digits: merged.digits,
        counter
    });
}export{totp};