https://fuldeka.github.io/blog/Recent content in Blog on fuldeka's homepageHugoen-usSat, 05 Sep 2026 11:40:00 +0200https://fuldeka.github.io/blog/tpm2-pin-encryption-schemes-evaluating-and-enhancing-security/Sat, 05 Sep 2026 11:40:00 +0200https://fuldeka.github.io/blog/tpm2-pin-encryption-schemes-evaluating-and-enhancing-security/<p><strong>TL;DR:</strong> Analyzing vulnerabilities in TPM2+PIN schemes and walking through an <a href="https://github.com/systemd/systemd/pull/41859">implementation</a> for <code>systemd-cryptenroll</code>, ensuring a security profile that is <strong>no less robust than</strong> traditional password-based schemes.</p> <h2 id="why-tpm-based-encryption">Why TPM-based encryption?</h2> <p>Encrypted disks are usually protected with passwords or passphrases. Assuming a <strong>truly random</strong> password of <strong>sufficient length</strong> is used and stretched by the encryption software, using a memory-hard <a href="https://en.wikipedia.org/wiki/Key_derivation_function">KDF</a> like <a href="https://en.wikipedia.org/wiki/Argon2">Argon2</a>, chances of anyone successfully performing a brute-force attack are virtually hopeless under most circumstances. Unfortunately, humans are poor at generating randomness, and because passwords created by humans are never as clever as they seem, most passwords end up being weak.<sup id="fnref:1"><a href="#fn:1" class="footnote-ref" role="doc-noteref">1</a></sup></p>