https://cryspen.com/tags/hndl/Recent content in HNDL on CryspenHugoen-usMon, 02 Feb 2026 00:00:00 +0000https://cryspen.com/post/psq-announce/Mon, 02 Feb 2026 00:00:00 +0000https://cryspen.com/post/psq-announce/<p>We&rsquo;re pleased to announce the <a href="https://github.com/celabshq/libcrux/tree/main/libcrux-psq">PSQ protocol</a> for establishing a hybrid post-quantum shared secret between two parties.</p> <p>Cryptographic protocols, which exclusively rely on classical public key cryptography for establishing shared secrets, may be vulnerable to <a href="https://en.wikipedia.org/wiki/Harvest_now%2C_decrypt_later">harvest-now-decrypt-later</a> (HNDL) quantum attacks. However, many protocols in widespread use today allow injecting a previously established pre-shared key (PSK) into the computation of the shared secret. If we can establish this pre-shared key in a way that is secure against HNDL attackers, we can provide an easy way of protecting many applications without having to touch their internals.</p>