Decrypt decrypts an AES encrypted message using the provided key. The key
must be 16, 24 or 32 byte broad to select either AES-128, AES-192 or AES-256.
Encrypt uses AES to securly encrypt a plaintext using the provided key.
The key must be 16, 24 or 32 byte broad to select either AES-128, AES-192 or
AES-256.