crypto and schema library for TUF and in-toto

 securesystemslib provides a high-level interface to cryptographic functions.
 It supports public-key and other cryptographic algorithms, such as ECDSA,
 Ed25519, RSA, SHA256, SHA512, etc. and a schema definition and validation
 framework.
 .
 securesystemslib is developed at the Secure Systems Lab of NYU and is used by
 the Python implementations of The Update Framework (TUF) and the software
 supply chain integrity framework in-toto.