Arjen Lentz
Arjen Lentz started programming as a teenager in the early ’80s, using a PDP-8 at the local computer club and an Acorn BBC/B at home, where he also tinkered with electronics. These were the days when computers did nothing unless you coded them yourself, so he explored (dis)assembly, bulletin boards, and modems. However, recognising the limited legal career opportunities in those areas, he shifted his focus to C programming as a profession, making use of his data communications and low-level programming skills.
Beyond custom projects for clients, Arjen wrote and refactored significant portions of code for the BBS and FidoNet community. His work included:
- The Xenia Mailer (based on The-Box by his friend Jac Kersing),
- The Xenia Email reader and editor,
- A fresh implementation of Zmodem to improve connections over unreliable satellite links, preventing costly protocol deadlocks (along the way, he identified a key design flaw in the protocol that caused those deadlocks),
- The Hydra bidirectional file transfer protocol, designed to make the most of the bandwidth offered by high-speed V.32bis modems.
When OS/2 arrived, Arjen embraced it eagerly, as (Double)DOS could only do so much. OS/2 Warp (GUI quirks aside) was a solid environment, as was the Watcom C/C++ compiler. Later, Slackware Linux arrived by post from Walnut Creek on CDs. Code from that era occasionally appears on github.com/lentzdev, mostly for nostalgia but sometimes still useful.
Around the turn of the millennium, Arjen moved to Australia, attracted by the space, climate, and new opportunities. Some time afterward, he joined MySQL as employee #25, working remotely for the ambitious startup. Some may remember him from this period, particularly for his talk at the NLUUG Voorjaarsconferentie 2003, where Bram Molenaar chaired the programme. Arjen’s afternoon presentation explained how MySQL managed to build a profitable business while giving away its software for free.
After his time at MySQL, Arjen ran his own training and consulting business for 11 years before selling it and returning to the security field as a CISO. It turned out he had simply been ahead of his time: the market for security skills had yet to mature. Now, we all know that market is thriving, and coding experience is a fantastic additional asset, as is an understanding of how businesses work.
Today, while Arjen occasionally codes, he serves as Senior Technical Architect at Ravinn, a Queensland-based boutique cybersecurity company. He has a particular interest in fundamentally improving security. Last year, Arjen found and fixed a security bug in sudo.
Arjen doesn’t blog much these days but scribbles his opinions on:
- LinkedIn
- Mastodon: @arjenlentz@mastodon.social and @art461@infosec.exchange
He is dedicated to open source, most recently acting as treasurer for the Everything Open 2026 conference in Canberra.
Session
As a neuro-divergent practitioner of the arcane, I wield a rare and potent magic: pattern recognition. Once, I channelled this power solely into the art of programming. But lo! My craft has since expanded into the shadowy realm of security, where, with a fair degree of precision, I can peer into the future itself.
You doubt me? Ah, but I have a tool to focus my visions: a crystal ball.
When I unroll the parchment of a security fix—be it for software, firmware, or some other enchanted artifact—I feed its secrets into my orb. There, the mists part to reveal deeper truths:
- Where more vulnerabilities lurk (both kin and stranger),
- Which other creations of the same artisan may falter,
- And, most crucially, whether this vendor’s name shall soon darken the scrolls again.
"But how does this sorcery work?" you ask, eyes alight with curiosity.
Ah, patience, seeker! In this session, those gathered (whether in hall or through scrying glass) may earn a glimpse behind the curtain.
A warning, though:
Like all magic, this craft is a double-edged blade. Evil wizards already stalk the digital shadows, and we must outpace them. Our duty?
- To unmask the vulnerable,
- To expose the flaws,
- And, unlike those who merely slap on bandages (or "patches," as the mundanes call them), forge solutions that endure.
"What kind of solutions?" you wonder.
Oh, eager apprentice! All shall be revealed.
But know this: we must be swifter, sharper, and bolder than the darkness.
The fate of the realm depends on it.