openpgp-notes/book/source/03-cryptography.md

Cryptographic concepts/terms

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- Introduce cryptographic primitives/terms at a very superficial level
- Introduce visualizations for cryptographic primitives

Public-key cryptography

https://en.wikipedia.org/wiki/Public-key_cryptography

Asymmetric cryptographic key pairs

In many places, we'll deal with asymmetric cryptographic key pairs:

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A cryptographic keypair

A cryptographic key pair consists of a public and a private part. In this document, we'll show the public part of a cryptographic key in green, and the private part in red.

We'll usually visualize cryptographic keypairs in this more compact form:

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A cryptographic keypair, more compact representation

Note that in many contexts, only the public part is present (more on that later):

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Only the public part of a cryptographic keypair

Public-key cryptography in OpenPGP

OpenPGP makes heavy use of public-key cryptography. However, for historical reasons, OpenPGP uses the terms "public/secret" instead of "public/private."

So when reading the RFC, or other documentation, you will encounter the term "secret key," instead of the more common "private key."

Symmetric encryption

https://en.wikipedia.org/wiki/Symmetric-key_algorithm

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- visualization?

Symmetric cryptography in OpenPGP

Symmetric encryption is a core concept in OpenPGP. It usually comes up involving the term "session key."

"Session keys" in OpenPGP are symmetric cryptographic keys.

Hashing

Cryptographic signatures

AEAD