Notes on the Anthropic cryptographic blogpost

Status: Mostly a summary with some of my notes at the end. Anthropic released a blogpost yesterday (07/28/26) describing how Claude Mythos Preview found improved ways to attack some cryptographic algorithms. While neither of the attacks they describe are a current threat to any production systems, I do expect models to continue getting substantially better at this. I’m not any sort of cryptography expert though, and am not sure how much of a threat model this is. Two different attacks were cover...