Simon Willison’s Weblog

Shamir Secret Sharing (via) Cracking war story from Max Levchin about the early years of PayPal, in which he introduces an implementation of Shamir Secret Sharing to encrypt their master payment credential table... and then finds that the 3-of-8 passwords needed to decrypt it and bring the site back online don’t appear to work. # 11th August 2023, 3:48 pm

See this page fetch itself, byte by byte, over TLS (via) George MacKerron built a TLS 1.3 library in TypeScript and used it to construct this amazing educational demo, which performs a full HTTPS request for its own source code over a WebSocket and displays an annotated byte-by-byte representation of the entire exchange. This is the most useful illustration of how HTTPS actually works that I’ve ever seen. # 10th May 2023, 1:58 pm

Building a stateless API proxy (via) This is a really clever idea. The GitHub API is infuriatingly coarsely grained with its permissions: you often end up having to create a token with way more permissions than you actually need for your project. Thea Flowers proposes running your own proxy in front of their API that adds more finely grained permissions, based on custom encrypted proxy API tokens that use JWT to encode the original API key along with the permissions you want to grant to that particular token (as a list of regular expressions matching paths on the underlying API). # 30th May 2019, 4:28 am

China Demonstrates Quantum Encryption By Hosting a Video Call. This reads like pure science fiction. “Pan’s team first established a connection and generated a secure key between a ground station in Xinglong and the Micius satellite as it passed overhead, orbiting about 500 kilometers above Earth. [...] Next, the Chinese team waited for Micius to pass over Vienna, where their collaborators at the Austria Academy of Sciences were waiting to also receive the key from the satellite. Then, with the keys in hand, the groups initiated a video conference and used those keys to encrypt the video data through a standard VPN protocol.” # 8th October 2017, 2:49 am

Insurgents Hack U.S. Drones. The video feed rather than the control protocol, but still.... “Fixing the security gap would have caused delays, according to current and former military officials. It would have added to the Predator’s price. Some officials worried that adding encryption would make it harder to quickly share time-sensitive data within the U.S. military, and with allies.” # 17th December 2009, 7:36 am

Keyczar (via) New open source cryptography toolkit from Google, designed to get algorithm selection, key rotation and versioning right so you don’t have to. Java and Python versions are available; the Python version depends on PyCrypto. # 13th August 2008, 1:20 pm