I build web applications and I'm into web application security. I like to speak about secure development. My mission is to teach web developers how to build secure and fast web applications and why. (more about me, contact)

My trainings

Public trainings

Come to my public trainings, everybody's welcome:

Trainings in Prague are held regularly in the middle of March, June, September, and December, in other cities irregularly.

In-house trainings

Any public training can also be turned into an in-house training. As an extra, I offer these in-house-only courses:

Looking for Introduction to PHP, Classes and objects in PHP? I've handed them over to Martin Hujer. I've discontinued Web application performance, Martin Michálek runs a similar training.

My articles

Using JavaScript to modify URLs and hide fbclid
November 7, 2018

Roughly two weeks ago, Facebook started adding a tracking parameter, fbclid (Facebook click id?), to all external links users share. And I didn't like it so I'm hiding it.

(read more…)

Disable TLS 1.0 & 1.1 today

Microsoft, Google, Apple & Mozilla announced yesterday that they're removing TLS 1.0 and TLS 1.1 protocols from Internet Explorer, Edge, Chrome, Safari & Firefox browsers in the beginning of 2020. Your visitors most probably don't use them already so you can disable them in your server configs today. But let's verify that first using the “Handshake Simulation” tool available in the SSL Labs Server Test.

(read more…)

Browsers are hiding the padlock and it's a Good Thing™
October 15, 2018

Magical properties are often attributed to the padlock icon 🔒 which marks “secure” pages. For example, you'll often hear that the icon indicates trustworthy websites that won't abuse your data and passwords. The padlock is gradually being removed and that's a Good Thing™. But why?

(read more…)

All articles

My talks


Upcoming talks

…at your event or conference, let me know!


January 14, 2019, PHP UserGroup Dresden Meetup I/2019 – CTF & Security (45 minutes)

Posilujeme defenzivu s Michalem Špačkem aneb Branky, body, bezpečnost
November 29, 2018, Livesport Talk VII (30 minutes)

Úniky dat, co to vůbec je a jak na ně reagovat
November 15, 2018, WebTop100 2018 (25 minutes)

Cracking passwords, or why use password_hash()
October 28, 2018, phpCE 2018 (50 minutes)

Vyhledávejte na netu jako MacGyver
October 6, 2018, LinuxDays 2018 (50 minutes)

All talks

Me answering questions

Blokování webů a stránek
June 4, 2016, Český rozhlas Online Plus

Na 11. srazu Na volné noze
June 4, 2016, 11. sraz Na volné noze

Webový vývojář musí mít hackerské myšlení
May 30, 2016, Kyberbezpečnost.cz

Hlavní je používat hlavu, ale ne na hesla
May 3, 2016, Host Radiožurnálu

Jak zvýšit zabezpečení vašeho webu?
February 17, 2016, MladýPodnikatel.cz

All interviews