Contact form spam protection

We use self-hosted ALTCHA software to protect against automated inquiries. When submitting, your browser solves a short computational task that our server verifies. This protection does not set cookies or transmit data to a CAPTCHA provider. To limit abuse, our server processes your IP address and the email address you enter, storing keyed verification hashes and timestamps. Repeated content is also identified only by a keyed hash. Counters consider at most 24 hours; expired entries are cleared when their storage partition is accessed. Each solved challenge is valid for ten minutes and can be used once. This supplements the privacy policy as of 8 September 2026.