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75 lines
3.5 KiB
Markdown
75 lines
3.5 KiB
Markdown
# Introducing OpenPGP
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This documentation project seeks to introduce OpenPGP concepts and functionalities to software developers who wish to use it in their projects.
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This document describes [OpenPGP version 6](https://datatracker.ietf.org/doc/draft-ietf-openpgp-crypto-refresh/), with occasional remarks about differences to earlier versions.
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This text is *not* intended as a guide for end-users of OpenPGP-related software.
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## What is OpenPGP?
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OpenPGP is an open standard for cryptographic operations. OpenPGP supports the secure delivery of files and messages between a sender and a recipient as well as verification of the sender. OpenPGP is an outgrowth of the ["Pretty Good Privacy (PGP)"](https://en.wikipedia.org/wiki/Pretty_Good_Privacy) encryption program and has many widely used and interoperable implementations.
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{::comment}
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Heiko, let's be sure to create our own page on interoperability instead of linking to this
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{:/comment}
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## Who is the audience for this document?
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Three groups of people interact with OpenPGP:
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1. End-users, who use software that contains OpenPGP functionality (e.g., the Thunderbird email software)
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2. Software developers who build applications that contain OpenPGP functionality
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3. Implementers of libraries or software that handles the processing of internal OpenPGP data structures
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This document is focused on software developers who use OpenPGP functionality in their software projects. It is not intended for end-users.
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{::comment}
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Heiko, we should elaborate a bit on why here
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{:/comment}
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Thus, this text describes OpenPGP at the "library-level," teaching concepts that will help software developers get started as a user of any implementation
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(e.g., OpenPGP JS, Sequoia PGP).
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### Requirements
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We presuppose solid knowledge of software development concepts and of general cryptographic concepts.
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OpenPGP is a system based on well-understood cryptographic building blocks.
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We describe the properties of the OpenPGP system and how to use it.
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### A companion for the OpenPGP RFC
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```
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The RFC explains lots of details (which bit goes where) that are crucial
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for implementers, but unimportant for software developers who use OpenPGP
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through a library.
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```
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The [OpenPGP RFC](https://datatracker.ietf.org/doc/draft-ietf-openpgp-crypto-refresh/)
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defines *"the message formats used in OpenPGP"* to *"provide encryption with
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public-key or symmetric cryptographic algorithms, digital signatures,
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compression and key management"*.
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The RFC, as a standards document, is mainly aimed at the third group:
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Implementers of software that handles internal OpenPGP data structures.
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In that context, the nitty-gritty of which bit of data goes where is crucial.
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For software developers using OpenPGP through a library, however, it is not.
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This document describes OpenPGP concepts at the "library" level of abstraction,
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and ignores most details about how OpenPGP artifacts are encoded at the lowest level.
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The idea is to go over various common OpenPGP artifacts, as they are
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currently used, to get an overview.
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### Covering versions
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We will mainly cover v6 of OpenPGP, but occasionally point out
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differences to previous versions.
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Version 4 of OpenPGP will remain relevant for a number of years,
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and some OpenPGP version 3 artifacts are still in use as of this writing (in 2023).
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For example, the RFC states that implementations MAY accept version 3 signatures.
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Handling version 3 artifacts is relevant in some contexts, where dealing with
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historical OpenPGP material is required.
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Where differences between versions may be relevant to application developers,
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we will point them out.
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