Lightweight tools for the cryptic!
LIPTK's goals are to provide a opinionated, yet flexible specification for providing cryptographic primitives (ie. cleartext, ciphertext, signatures, etc) with a way to encode and decode them safely.
LIPTK specifies sane defaults for algorithms and their parameters, and is designed so they can be composed seamlessly together. To do this, LIPTK provides generic primitives with concrete types and a format for encoding them to binary (and back).
This specification is inspired by libsodium as it specifies a small suite of algorithms that have been vetted quite extensively, however LIPTK strives to be more flexible in respect to providing more alternative algorithms, and a future proof way of using them. Implementations of this specification may actually use libsodium internally to provide support for algorithms.
You can also draw parallels between LIPTK and the OpenPGP message format, but LIPTK's binary format is designed to provide the bare minimum, and is lightweight in comparison. You could build a protocol using LIPTK primitives similar to OpenPGP (which this library wants you to be able to do), but a higher level protocol is not in the scope of this project.
Rather than defining a strict specification on how you should talk, LIPTK provides you primitives you can use to compose your own conversation easily.
For example, a format for encoding ed25519 signature parameters is provided, and can be wrapped in a generic signature, which in turn can be passed over the network, without worrying how to externally specify what sort of signature it is. A LIPTK decoder implementation can then unwrap the signature to get it's parameters to verify data.