Warmwasserwerfer Blog

Tag: crypto

Closer Look at the Double Ratchet

In this post I try to explain the Double Ratchet Algorithm that drives the cryptography behind OMEMO and Signal. This is the second part of my series about the crypto behind OMEMO.

April 15, 2019
Shaking Hands With OMEMO: X3DH Key Exchange

In this blog post I take a detailed look at how the Extended Triple Diffie-Hellman Key Exchange (X3DH) works. This algorithm is part of the cryptography that drives OMEMO.

April 4, 2019
Unified Encrypted Payload Elements for XMPP

An envelope hiding the original message – Image by Bru-nO

This is a proposal to extract the element encryption principle from OpenPGP for XMPP to make it applicable to other encryption protocols.

January 17, 2019
QR-Code Generator for OMEMO

I wrote a small tool that generates QR-Codes for OMEMO fingerprints.

November 3, 2018
Starting to use the Fellowship Card

I recently became a fellow of the FSFE and so I received a nice letter containing the FSFE fellowship OpenPGP smartcard. After a quick visual examination I approved the card to be *damn cool*, even though the portrait format of the print of it still confuses me when I look at it. I especially like,…

December 15, 2016