Hi, due to this [vulnerability](https://nvd.nist.gov/vuln/detail/CVE-2018-10903) you should update module [dependency](https://github.com/bigchaindb/cryptoconditions/blob/4007f53dba33278c12775bf1879d26737c648340/setup.py#L77) Tanks
