Package auth contains one-time password authentication functionality for implementing authentication in a system design.

Package public contains utilities for public key encryption with Curve25519 and digital signatures with Ed25519.

Package secret contains utilities for encrypting and decrypting data with secret keys; it is aimed primarily at password-based encryption.

Package store contains two types of secure stores: a store that contains secrets, such as might be used by a password manager, and a store that contains public keys, such as might be used by a PGP-like system.

Package tlv implements a tag-length-value encoding scheme for use in packing flat data structures with a fixed format.

Package util contains utility code common to the cryptutils programs.