Create a cryptographic module

[yanmarques]

Description

A module with utility functions/methods for applying cryptographic algorithms.

Requirements

Try to be as transparent as possible.

• [x] 1. has the following functionality:
  • [x] 1.1 calculates the hash sum of a given block
  • [x] 1.2 verify a signature using a public key
  • [x] 1.3 create signatures from given arbitrary data
  • [x] 1.4 load and dump asymmetric keys
  • [x] 1.5 encode public key into a safe format

[yanmarques]

Requirement: 1.1

A function called block_hashsum which correctly dumps the object into a string, taking care of always get the same result given same block attributes, then applying a default hashing function.

The default algorithm is SHA256.

[yanmarques]

Requirement: 1.2, 1.4, 1.5

The cryptography module will be used to handle the cryptographic primitives.

It consists from an object with the following methods:

• was_signed: which verifies the validity of a signature
• public_to_b64: converts the public key into a base64 encoded content
• b64_to_public_key: convert a base64 encoded content into a public key object

[yanmarques]

Requirement: 1.3, 1.4

It consists from an object, which extends the object from requirements 1.2, 1.4, 1.5, containing the following methods:

• sign: create a detached signature from a given arbitrary data
• private_to_pem: encode the private key into a readable standard PEM encoding