Some Random Idiot

embroidery, networks, programming, feelings

Faithful High Resolution Textures

I discovered a while ago that some games companies charge extra for “high resolution textures” for their games. This phrase stuck with me until it finally found an outlet: it obviously needs to be rendered in glorious 4-color CGA as a puzzle solution to the 1987 DOS implementation of the popular American game show, “Wheel of Fortune”.

Ditch That AWS Build Host

In honor of the transnational strike on Amazon this week, here are instructions for moving your AWS unikernels to a cloud that used to claim it wasn’t evil. You might also be interested in establishing a picket line for your packets. This blog originally ran on Amazon EC2. Since early 2017, it’s been running on a different tech behemoth’s massive public cloud. The deployment process is considerably easier and faster on this alternative public cloud – I first saw it as a live demo given by Michael Bright and immediately knew I wanted to replace my AWS pipeline with it.

Whacking the Bitcoin Piñata

@yomimono or @hannesm surely know if people have tried crowbar on the BTC Pi̱ata. Р

tl;dr - yes, and it seems that ocaml-x509 is not trivially easy to trick.


The Bitcoin Piñata

In 2015 David Kaloper-Mersinjak and Hannes Mehnert released ocaml-tls, an implementation of TLS (formerly known as SSL) written fully in OCaml. A full writeup of the stack is available in their Usenix Security 2015 paper, and as a series of blog posts on To accompany the release they also deployed a fully-automated bug bounty for the security stack Рthe bitcoin pi̱ata.

The piñata will establish TLS connections only with endpoints presenting a certificate signed by its own, undisclosed certificate authority, but allows an attacker to easily listen to the encrypted traffic. The piñata always sends the same plaintext in such a connection: the private key to a wallet containing approximately 10 bitcoin. If the attacker can decrypt the ciphertext, or trick the piñata into negotiating a TLS connection with another host and disclosing the key, the information (and therefore the money) is theirs.


Crowbar is a library for writing tests. It combines a property-based API (like QuickCheck) with a coverage-driven generator of test cases (like the fuzzer American Fuzzy Lop). Crowbar tries to find counterexamples to stated properties by prioritizing the generation of test cases which touch more code. It is very good at finding counterexamples.

Testing ocaml-x509

TLS connections are usually authenticated via X509 certificates. ocaml-tls uses ocaml-x509 for this purpose, which is written as a standalone library. There is a clear separation of concerns between ocaml-x509 and ocaml-tls, and a straightforward API for certificate operations in ocaml-x509; both features help tremendously in writing tests for certificate handling.