Simon Willison’s Weblog

4 items tagged “thomasptacek”

2021

API Tokens: A Tedious Survey. Thomas Ptacek reviews different approaches to implementing secure API tokens, from simple random strings stored in a database through various categories of signed token to exotic formats like Macaroons and Biscuits, both new to me. Macaroons carry a signed list of restrictions with them, but combine it with a mechanism where a client can add their own additional restrictions, sign the combination and pass the token on to someone else. Biscuits are similar, but “embed Datalog programs to evaluate whether a token allows an operation”. # 25th August 2021, 12:12 am

2020

Sandboxing and Workload Isolation (via) Fly.io run other people’s code in containers, so workload isolation is a Big Deal for them. This blog post goes deep into the history of isolation and the various different approaches you can take, and fills me with confidence that the team at Fly.io know their stuff. I got to the bottom and found it had been written by Thomas Ptacek, which didn’t surprise me in the slightest. # 30th July 2020, 10:19 pm

How CDNs Generate Certificates. Thomas Ptacek (now at Fly) describes in intricate detail the challenges faced by large-scale hosting providers that want to securely issue LetsEncrypt certificates for customer domains. Lots of detail here on the different ACME challenges supported by LetsEncrypt and why the new tls-alpn-01 challenge is the right option for operating at scale. # 26th June 2020, 12:03 am

2007

A Roundup Of Leopard Security Features (via) Thomas Ptacek’s overview of the new security features in Leopard. Guest Accounts are worthless from a security P.O.V., but I still plan to use one for our PowerBook that’s now just a media player. # 31st October 2007, 5:30 pm