Cryptographic Protocol

This chapter describes the cryptographic design of the Penumbra protocol, described in more detail in the following sections:

• The Addressses and Keys section describes the Penumbra key hierarchy and diversified addresses.

• The Notes section describes Penumbra’s private notes and their contents.

• The Transaction Cryptography section describes the symmetric keys used at the level of an individual transaction.

Notation

We use the following notation in this chapter:

• $\mathbb{G}$ denotes the decaf377 group;
• ${\mathbb{F}}_q$ denotes the BLS12-377 scalar field of order $q$;
• ${\mathbb{F}}_r$ denotes the decaf377 scalar field of order $r$.