demo = $2y$10$Zjk5YzQ4ZTlhMzNlNTUzMO3Wnm1FqXmAb6/4DmyptNGoEdWGLwls.

function password_encrypt($password) {
  $hash_format = "$2y$10$";   // Tells PHP to use Blowfish with a "cost" of 10
  $salt_length = 22;                    // Blowfish salts should be 22-characters or more
  $salt = generate_salt($salt_length);
  $format_and_salt = $hash_format . $salt;
  $hash = crypt($password, $format_and_salt);
    return $hash;
}

function generate_salt($length) {
  // Not 100% unique, not 100% random, but good enough for a salt
  // MD5 returns 32 characters
  $unique_random_string = md5(uniqid(mt_rand(), true));
    // Valid characters for a salt are [a-zA-Z0-9./]
  $base64_string = base64_encode($unique_random_string);
    // But not '+' which is valid in base64 encoding
  $modified_base64_string = str_replace('+', '.', $base64_string);
    // Truncate string to the correct length
  $salt = substr($modified_base64_string, 0, $length);
    return $salt;
}

function password_check($password, $existing_hash) {
    // existing hash contains format and salt at start
  $hash = crypt($password, $existing_hash);
  if ($hash === $existing_hash) {
    return true;
  } else {
    return false;
  }
}