Jose\Util\BigInteger::createFromBinaryString PHP Method

    public static function createFromBinaryString($value)
    {
        Assertion::string($value);
        $value = '0x' . bin2hex($value);
        return new self($value, 16);
    }

 /**
  * Octet-String-to-Integer primitive.
  *
  * @param string $x
  *
  * @return \Jose\Util\BigInteger
  */
 private static function convertOctetStringToInteger($x)
 {
     return BigInteger::createFromBinaryString($x);
 }