I doubt it. The one challenge with hex2bn is that it expects a `BIGNUM **` so we'll have to do something like:

```python
bn_ptr_ptr = ffi.new("BIGNUM **")
BN_hex2bn(bn_ptr_ptr, hex_num)
bn = bn_ptr_ptr[0]
bn = ffi.gc(bn, lib.BN_free)
```