This page lists releases of Hydrilla before version 3. Since version 3 Hydrilla is distributed together with Haketilo proxy. Please take a look at the Haketilo downloads page for a list of newer releases.
Public keys for verification of signatures are the ones from koszko.org.
PGP key fingerprint: E972 7060 E3C5 637C 8A4F 4B42 4BC5 221C 5A79 FD1A
Signify public key: RWQSf2wUdpjAtrmt7D3t9iHrHFL/GpqXOF+NxECx8ck7swrx6tNzDkM9
You might want to read our instructions on signature verification.