OpenPGP data types and associated machinery.
This crate aims to provide a complete implementation of OpenPGP as defined by RFC 4880 as well as several extensions (e.g., RFC 6637, which describes ECC cryptography for OpenPGP, and RFC 4880bis, the draft of the next OpenPGP standard). This includes support for unbuffered message processing.
A few features that the OpenPGP community considers to be deprecated (e.g., version 3 compatibility) have been left out as well as support for functionality that we consider to be not only completely useless, but also dangerous (e.g., support for unhashed signature subpackets). We have also updated some OpenPGP defaults to avoid foot guns (e.g., this crate does not fallback to IDEA, but instead assumes all OpenPGP implementations understand AES). If some functionality is missing, please file a bug report.
A non-goal of this crate is support for any sort of high-level, bolted-on functionality. For instance, RFC 4880 does not define trust models, such as the web of trust, direct trust, or TOFU. Neither does this crate. RFC 4880 does provide some mechanisms for creating trust models (specifically, UserID certifications), and this crate does expose those mechanisms.
We also try hard to avoid dictating how OpenPGP should be used. This doesn't mean that we don't have opinions about how OpenPGP should be used in a number of common scenarios (for instance, message validation). But, in this crate, we refrain from expressing those opinions; we expose an opinionated, high-level interface in the sequoia-core and related crates. In our opinion, you should generally use those crates instead of this one.