https://github.com/soatok/rawr-x3dh
TypeScript Implementation of X3DH
https://github.com/soatok/rawr-x3dh
crypto cryptography diffie-hellman ed25519 furry javascript key-agreement libsodium nodejs typescript x25519 x3dh
Last synced: 22 days ago
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TypeScript Implementation of X3DH
- Host: GitHub
- URL: https://github.com/soatok/rawr-x3dh
- Owner: soatok
- License: isc
- Created: 2020-11-16T23:32:30.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2023-03-15T06:27:39.000Z (about 2 years ago)
- Last Synced: 2025-04-10T15:34:28.968Z (26 days ago)
- Topics: crypto, cryptography, diffie-hellman, ed25519, furry, javascript, key-agreement, libsodium, nodejs, typescript, x25519, x3dh
- Language: TypeScript
- Homepage: https://soatok.blog/2020/11/14/going-bark-a-furrys-guide-to-end-to-end-encryption/
- Size: 136 KB
- Stars: 91
- Watchers: 5
- Forks: 5
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
Awesome Lists containing this project
README
# 
TypeScript implementation of X3DH, as described in
***[Going Bark: A Furry's Guide to End-to-End Encryption](https://soatok.blog/2020/11/14/going-bark-a-furrys-guide-to-end-to-end-encryption/)***.
[](https://patreon.com/soatok)
[](https://travis-ci.org/soatok/rawr-x3dh)
[](https://npm.im/rawr-x3dh)
## [OwO](https://soatok.files.wordpress.com/2020/09/soatoktelegrams2020-06.png) What's This?
This library implements the [Extended Triple Diffie-Hellman](https://signal.org/docs/specifications/x3dh/)
key exchange, with a few minor tweaks:
1. Identity keys are Ed25519 public keys, not X25519 public keys.
[See this for an explanation](https://soatok.blog/2020/11/14/going-bark-a-furrys-guide-to-end-to-end-encryption/#why-ed25519-keys-x3dh).
2. Encryption/decryption and KDF implementations are pluggable
(assuming you implement the interface I provide), so you aren't
married to HKDF or a particular cipher. (Although I recommend hard-coding
it to your application!)
## Installation
First, you'll want to install this library via your package manager.
```terminal
npm install rawr-x3dh
```
If you're working server-side, you'll also want to install [sodium-native](https://www.npmjs.com/package/sodium-native),
so that [sodium-plus](https://www.npmjs.com/package/sodium-plus) will run faster.
If you're working in a browser or browser extension, don't install sodium-native.
## Usage
First, you'll want to import the X3DH class from our module.
```typescript
import { X3DH } from 'rawr-x3dh';
const x3dh = new X3DH();
```
Note: You can pass some classes to the constructor to replace my algorithm implementations
for your own.
```typescript
import { X3DH } from 'rawr-x3dh';
const x3dh = new X3DH(
sessionKeyManager, /* SessionKeyManagerInterface */
identityKeyManager, /* IdentityKeyManagerInterface */
symmetricEncryptionHandler, /* SymmetricEncryptionInterface */
keyDerivationFunction /* KeyDerivationFunction */
);
```
Once your X3DH object's instantiated, you will be able to initialize handshakes
either as a sender or as a recipient. Then you will be able to encrypt additional
messages on either side, and the encryption key shall ratchet forward.
```typescript
const firstEncrypted = await x3dh.initSend(
'recipient@server2',
serverApiCallFunc,
firstMessage
);
```
The `serverApiCallFunc` parameter should be a function that sends a request to the server
to obtain the identity key, signed pre-key, and optional one-time key for the handshake.
See the definition of the `InitClientFunction` type in `lib/index.ts`.
Once this has completed, you can call `encryptNext()` multiple times to append messages
to send.
```typescript
const nextEncrypted = await x3dh.encryptNext(
'recipient@server2',
'This is a follow-up message UwU'
);
```
On the other side, your communication partner will use the following feature.
```typescript
const [sender, firstMessage] = await x3dh.initRecv(senderInfo);
const nextMessage = await x3dh.decryptNext(sender, nextEncrypted);
```
Note: `initRecv()` will always return the sender identity (a string) and the
message (a `Buffer` that can be converted to a string). The sender identity
should be usable for `decryptNext()` calls.
However, that doesn't mean it's trustworthy! This library only implements
the X3DH pattern. It doesn't implement the
[Gossamer integration](https://soatok.blog/2020/11/14/going-bark-a-furrys-guide-to-end-to-end-encryption/#identity-key-management).
## Should I Use This?
Don't use it in production until version 1.0.0 has been tagged.
The API can break at any moment until that happens (especially if
I decide I hate the default key management classes I wrote).
However, feel free to test and play with it.
## Questions and Answers
### Any Interest in Porting This to $LANG?
I'd love to port this to more languages! That will also allow me to write end-to-end integration tests.
As long as there's a good [libsodium implementation](https://libsodium.gitbook.io/doc/bindings_for_other_languages),
it should be doable.
However, I don't have *nearly* as much free time as I'd like, so I can't commit to
building or supporting multiple implementations right now.
Conversely, if you've ported this to another language, let me know and I'll maintain
a list here:
* (Currently, none.)
### Why "Rawr"?
The canonical abbreviation for the eXtended 3-way Diffie Hellman
deniable authenticated key exchange is X3DH.
There is a [cursed furry copypasta/meme](https://knowyourmeme.com/memes/notices-bulge-owo-whats-this)
that begins with "rawr x3". The juxtaposition of "x3" and "X3DH" is too perfect
an opportunity for dumb jokes to pass up.
### Is this a furry thing?
[](https://soatok.blog/2020/11/14/going-bark-a-furrys-guide-to-end-to-end-encryption/)
And remember: It's not *furry trash*, it's *yiff-raff*.
#### Why? Just, Why?
I've written a lot of words to answer this line of questioning already on [my blog](https://soatok.blog).
You will probably find the answer you're seeking [here](https://soatok.blog/2020/07/09/a-word-on-anti-furry-sentiments-in-the-tech-community/)
or [here](https://soatok.blog/2020/10/23/solving-for-why-furry-blogging-about-cryptography/).
#### This is Unprofessional
Folks often say there's an XKCD for Everything! And thus:
[](https://xkcd.com/137/)
#### Who Made That Awesome Project Logo?
[Sophie](https://twitter.com/loviesophiee) made it.