Developer Maurycyz hides readable messages inside TLS certificate public keys
The gist
Developer Maurycyz published a method to build a working TLS certificate with a message spelled inside its RSA public key.
The trick is a protest against certificate cost and expiry, but it weakens the key's entropy.
How it unfolded
- Nov 8, 2026A signed certificate for maurycyz.com was issued, valid through Feb 6, 2027.
- Nov 9, 2026Maurycyz published "Horible public key tricks" describing how to generate a functional TLS certificate carrying a readable message inside its RSA public key.
- Nov 10, 2026LavX News published an article on the project, and the post appeared on Hacker News with 30 points and 11 comments.
Key terms
- TLS certificate
- A digital certificate used in the TLS protocol to authenticate parties and enable encrypted network communications.
- RSA public key
- The public component of an RSA asymmetric key pair, used to encrypt data or verify signatures.
- entropy
- A measure of the average uncertainty or information content associated with a random variable's possible outcomes.
Source: Wikipedia