Keyless Signature Infrastructure (KSI) is a technology for protecting the integrity of digital data without the need to worry about keeping any secrets. Quite the opposite, the security of the system relies, aside from mathematics, on publishing the trust anchors as widely witnessed events.

In this talk, I will present a new digital signature scheme which can be used as a quantum-immune replacement for RSA. The new scheme combines KSI data signatures with hash sequence authentication mechanisms to significantly limit the potential liability in case of security breaches and simplify token revocation compared to the Public Key Infrastructure (PKI) solutions. As the scheme is based solely on cryptographic hash functions and does not use any trapdoor functions, it is, according to the current knowledge, also resistant to quantum computational attacks.