Field notes
Notes from the field.
Short, practical writing on post-quantum migration, key custody and offensive security by Kyeson Blake Utley. Subscribe via RSS.
Harvest now, decrypt later: is your data already exposed?
Why data encrypted today can be read by tomorrow's quantum computers, how to use Mosca's inequality to tell whether you're already late, and what to fix first.
Stateful signatures and the backup that ate your keys
LMS and XMSS are standardized, quantum-safe and fast. They also break catastrophically if a one-time key is used twice. Here's how ordinary operations cause that, and how to prevent it.
What Q-Day means for crypto custody
Bitcoin and Ethereum rely on elliptic-curve signatures that a large quantum computer could break. Which coins are exposed first, why address reuse matters, and what custodians can do now.