Decrypt decrypts data using 256-bit AES-CTR and provides message authentication verifying the HMAC-512_256 signature.

Encrypt encrypts data using 256-bit AES-CTR and provides message authentication by signing the data with HMAC-512_256.

NewEncryptionKey generates a random 256-bit key for Encrypt() and Decrypt().

NewRandomIV generates a random 128-bit IV for use with AES encryption.