Implement the possibility to create BigNums from their ffi counterpart

        })

    }

    pub fn new_from_ffi(orig: *mut ffi::BIGNUM) -> Result<BigNum, SslError> {

        if orig.is_null() {

            panic!("Null Pointer was supplied to BigNum::new_from_ffi");

        }

        unsafe {

            let r = ffi::BN_dup(orig);

            if r.is_null() {

                panic!("Unexpected null pointer from BN_dup(..)")

            } else {

                Ok(BigNum(r))

            }

        }

    }

    pub fn new_from_slice(n: &[u8]) -> Result<BigNum, SslError> {

        BigNum::new().and_then(|v| unsafe {

            try_ssl_null!(ffi::BN_bin2bn(n.as_ptr(), n.len() as c_int, v.raw()));