Tatu Ylonen - Research Home Page

This will be the personal and research home page of Tatu Ylonen (also known as Tatu Ylönen or Tatu Yloenen).

Computational Linguistics, Semantics, and AI

I'm currently working on new approaches to understanding natural language by computers. There is not much public information on this yet, but check out the following:

I'm also working on various highly scalable machine-learning approaches.

In the medium term I'm particularly interested in semantic parsing - extracting and representing the meaning of documents.

Publications

Cybersecurity

I wrote the original SSH (Secure Shell), which has since evolved into OpenSSH and various other versions. It now ships with every Unix, Linux, and Mac computer and is available for every platform. It is the de facto tool for system and network administration over computer networks. I've also done a lot of work in SSH key management, for both user authentication keys and host keys.

I'm currently interested in SSH key management and post-quantum cryptography and how to design security protocols for the post-quantum age. It does look like quantum computers might actually be becoming a reality. It is time to start preparing, as the changes are going to affect an awfully wide variety of protocols and systems, most of which will need to be upgraded or replaced - and many of those would normally only be replaced after 10-20 years!

See preprint Challenges in Managing SSH Keys - and a Call for Solutions

See bibliography on SSH and SSH key management.

Database research

I used to be a database researcher. Here is some work from that era. We introduced various new ideas into concurrent, scalable shadow paging, including striping and RAID built into the shadow paging mechanism, on-the-fly transaction-consistent snapshots, and fine-grained locking. My Master's thesis was on information retrieval - full text indexing. We also did operating system work, including porting the Mach operating system to a new processor architecture (which lead to me debugging and fixing bugs in GCC, GNU linker, and GDB and writing extensive kernel code).

Other links