https://github.com/benwr/zebra

https://github.com/benwr/zebra

Last synced: 3 months ago
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• Host: GitHub
• URL: https://github.com/benwr/zebra
• Owner: benwr
• Created: 2023-09-15T22:58:26.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2024-08-05T07:02:08.000Z (9 months ago)
• Last Synced: 2025-01-29T04:53:33.331Z (3 months ago)
• Language: Rust
• Size: 9.65 MB
• Stars: 2
• Watchers: 3
• Forks: 2
• Open Issues: 10
• Metadata Files:
  • Readme: README.md

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README

        
# Zebra: an app for creating and verifying ring signatures

![](zebra_desktop/zebra_head.png)

## What are ring signatures?

Say you want to publish some information. You want people to know that it was

published by someone trustworthy, with access to that information, but you

don't want them to know exactly *who* published it. For example, it might be

information about someone's misconduct, and you fear retaliation.

You can publish the information using a ring signature. To do this, you choose

a set of people that you want to include in the "ring": This is the set of

people who, to an observer, *might* have published the information. Then, you

sign the message using *your* private key, and *their* public keys.

Once you publish the information with a ring signature, anyone who knows the

public keys of the ring members (you and the other people whose keys you used)

can tell that *someone* in that group signed the message. But they can't tell

*which* person it was.

## Design

Zebra is designed with the following principles in mind, in order from most

important to least important:

1. Zebra should be a trustworthy implementation of the theory of ring

   signatures. If you observe a signed message, and the app successfully

   verifies the signature, you should be able to feel confident in the

   signature.

2. Zebra should be simple to use and hard to misuse. It should be almost

   trivial to create a signature, or import a key. It should be almost

   impossible to leak your private key, or compromise your anonymity within a

   ring.

3. Zebra should be implemented as simply as possible, with the minimum set

   of dependencies. The more crucial a piece of code is for providing the

   trustworthiness guarantee, the fewer dependencies it should have.

Zebra is a [dioxus](https://dioxuslabs.com) app. This means that the user

interface code can be understood by anyone with knowledge of web programming

and Rust, but the app relies on the operating system's web view rather than a

packaged browser. This improves resource usage somewhat compared to an electon

app.

### Cryptography

Zebra's ring signature implementation is based on the algorithm presented

in the book [Zero to Monero: Second

Edition](https://www.getmonero.org/library/Zero-to-Monero-2-0-0.pdf).

We use the [Ristretto group](https://ristretto.group/) as our prime order

group, and in particular the [dalek-cryptography](https://dalek.rs/)

implementation.

Public keys (technically, self-signed certificates) contain the requisite group

element, as well as a signature that verifies that the holder of the key claims

to be associated with the identity provided.

### Storage

Zebra uses [age](https://github.com/FiloSottile/age) to encrypt an extremely

simple database of keys. The password for this database is chosen randomly and

stored in the system's keychain. So the operating system will prompt the user

before allowing the database to be unlocked (on app start, or when modifying

the database or using a private key).

We try pretty hard to avoid exposing private keys to other apps. They aren't

stored in memory, except briefly when reading/writing the encrypted database,

or when performing a signing operation, or, of course, when explicitly sending

them to a new machine. When sending data to a remote machine, we use [Magic

Wormhole](https://github.com/magic-wormhole/magic-wormhole.rs) to ensure that

the transfer is encrypted end-to-end. We also use

[secmem-proc](https://github.com/niluxv/secmem-proc) to try to frustrate

attempts at tracing the process or reading core dumps / swap.

## Copyright Information

The icon file `zebra_head.png` is a modification of ["Zebra, Ngorogoro"](https://www.flickr.com/photos/woodlouse/3990713395) by Woodlouse

on Flickr. Unlike the rest of this repository, it is released under a [Creative

Commons Attribution-ShareAlike 2.0 Generic

License](https://creativecommons.org/licenses/by-sa/2.0/).

Some of the code in this repository is released under an MIT license.

Specifically, everything inside of the `age` and `age-core` directories, as

well as the `sign` and `verify` functions in `zebra_crypto/lib.rs`.

Everything else is the copyright of Kurt Brown.