DecodeMessage decodes the given message by separating out the token and comparing it with the derived token, returning an error if the message was invalid.

InitAesCrypto initializes an AesCrypto.

SignMessage signs the given message using hmac and appends it to the given message.

AesCrypto is an AES implementation of a Crypto with key size of 256 bits.

Crypto defines a simple interface for any struct that can encrypt and decrypt crypt data.