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Terms of use

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You may use everything on this site to learn, and teachers may use it in class; these terms explain the few rules that come with that.

Who are we?

This website is published by Duyutech BV, Slagmanstraat 26, 9080 Lochristi, Belgium, enterprise number 0762.516.604 (“we”, “us”). See the legal notice for full details. By using the site, you agree to these terms.

What is this site?

PKI Zero to Hero offers learning material about PKI and certificates: a handbook, a crash course, browser tools, error pages and related pages. It is an early edition. We check every claim against primary sources, and an independent expert review is in progress, but the material may still contain mistakes and will keep changing.

The learning material is free. These terms cover the material as it exists; they do not promise any particular future feature, level or date.

What may I do with the material?

All text, images, video, characters and code on this site are © 2026 Duyutech BV unless stated otherwise.

You may, free of charge:

  • read and use the material for your own learning;
  • print or save copies for your own use;
  • use the material for free classroom teaching: show it, print it and hand it out to your students in a school, university or adult-education class, as long as you do not charge for the material itself;
  • link to any page;
  • quote short passages, with a link to the page.

Always name the source: “PKI Zero to Hero, pkizerotohero.com”.

You may not, without our written permission:

  • republish the material, in full or in large parts, on another website, platform or publication;
  • sell the material, or include it in paid courses, paid training or products;
  • change the material and present it as ours, or present ours as yours;
  • use the name PKI Zero to Hero, the logo or the characters in a way that suggests we endorse you.

Ask us at info@pkizerotohero.com. We are happy to discuss other uses.

The tools

The tools run in your browser. What you paste into them is not sent to us. The tools are provided as they are, for learning and troubleshooting. Always confirm important results with your own systems and your certificate authority before you rely on them.

Accuracy and no warranty

We work hard to make the material correct, and we link to the primary sources (such as RFCs, the CA/Browser Forum’s requirements, NIST publications, browser root-program policies and EU law on EUR-Lex) so you can check them. Those sources are the authority; where they differ from our material, they win.

The site and its content are provided as they are and as available, without any warranty that they are complete, correct, up to date or fit for a particular purpose. The material is for learning. It is not professional, security or legal advice for your specific situation.

Liability

To the extent allowed by Belgian law, we are not liable for any damage that results from using, or being unable to use, the site, the material or the tools, including damage from decisions made on the basis of the material.

Nothing in these terms limits or excludes liability that cannot be limited or excluded by law, such as liability for our intentional or gross misconduct, or for death or personal injury caused by our fault. If you are a consumer, nothing in these terms affects the rights that consumer law gives you and that cannot be waived by contract.

We link to other websites, mainly primary sources. We are not responsible for their content or availability, and their own terms and privacy policies apply.

Changes to these terms

We may change these terms, for example when new features arrive. We will publish the new version on this page and update the date shown on it. The version on this page when you use the site applies.

Which law applies, and which courts?

These terms are governed by Belgian law. Any dispute will be handled by the courts of Ghent (Gent), Belgium.

If you are a consumer, this choice does not take away the protection of the mandatory rules of the country where you live, and you may also bring a case before the courts that consumer law allows you to use, such as the courts where you live.

Contact

Questions about these terms: info@pkizerotohero.com.