The Other Sean Byrne Doesn’t Exist
A fictitious employee of an Irish aircraft-parts company ended up on a U.S. government restricted-party list. Sixteen years later, companies keep mistaking me for him.
Sean Byrne
Security engineering leader. Building and scaling security programs at high-growth companies.
Latest posts
E2EE Key Storage Evolution & Passkey PRFs
Slides and notes from my Cork|Sec talk on the evolution of end-to-end encryption key storage, and why the WebAuthn PRF extension may collapse authentication and encryption roots into a single primitive.
The Fence Is Down
Anthropic pointed Claude at the Firefox codebase and found 22 zero-days in two weeks. The capability gap between AI and widespread exploitation won't last. The window to prepare is now.
Giving iOS Lockdown Mode Another Look
A leaked iPhone exploit framework avoids devices with Lockdown Mode enabled. For anyone who tried the feature early and gave up, it may be worth revisiting.
Passkeys and the Quiet Revolution in Corporate Crypto
Passkeys solve the authentication problem corporate IT has been fighting for decades. But the more interesting story is what happens when every employee has a hardware-backed key generation and storage facility in their pocket.
AMD’s Remote Execution Bug and the Limits of Responsible Disclosure
On AMD's insecure auto-updater, the responsible disclosure process, and why fixing the bug should be the beginning of accountability, not the end.
10DLC Will Do What Passkeys Couldn’t
SMS 2FA won't be killed by SIM swapping or SS7. It will be killed by the paperwork now standing between you and a six digit code.
Signal, Trust on First Use
On Trevor Perrin's talk about the TextSecure (Signal) protocol, and why authentication is the harder half of end-to-end encryption.
Small, Sharp Tools
On the AT&T Archives UNIX documentary, composition as a way to manage complexity, and why inspectable systems are easier to secure.