Thomas Ptacek
More info
- Affiliation
- Matasano, Latacora, Fly.io
- Known for
- IDS evasion, Cryptopals
Security researcher whose 1998 paper showed network intrusion detection could be fooled by design — and who later taught a generation of developers to break crypto.
Ptacek wrote "Insertion, Evasion, and Denial of Service" with Timothy Newsham at Secure Networks in 1998. The point was simple and unpleasant: an IDS listening on the wire does not see the same stream as the target host. With overlapping fragments, carefully chosen TTL values and packets only one side will accept, an attacker can show the sensor a harmless version and the victim the real one.
In 2005 he co-founded the consultancy Matasano, birthplace of the Cryptopals challenges, followed later by Latacora and Fly.io. As tptacek he is also one of Hacker News's most prolific commenters — not a title anyone applies for, but it has stuck.