Haketilo

/* uint8_to_hex is a separate function used in cryptographic functions. */

const uint8_to_hex =

      array => [...array].map(b => ("0" + b.toString(16)).slice(-2)).join("");

 * Asynchronously compute hex string representation of a sha256 digest of a

 * UTF-8 string.

async function sha256_async(string) {

    const input_ab = new TextEncoder("utf-8").encode(string);

    const digest_ab = await crypto.subtle.digest("SHA-256", input_ab);

    return uint8_to_hex(new Uint8Array(digest_ab));

#EXPORT sha256_async

/*

 * Generate a unique value that can be computed synchronously and is impossible

 * to guess for a malicious website.

 */

    const random_data = new Uint8Array(length);

    crypto.getRandomValues(random_data);

    return uint8_to_hex(random_data);