The security-facade implements IVOA's security model together with AstroGrid and EuroVO extensions. The facade consists in a class library for use in VO services and clients. It is used in most AstroGrid service-components and in the Astro Runtime. The facade presents a common API to classes from different sources. These are some of the main features available from the security facade: validation of digital signatures on requests to a SOAP service; signature of requests sent from a SOAP client; an SSL implementation for Apache Tomcat that allows authentication of clients using proxy certificates; classes to generate and validate certificate chains containing proxy certificates; client code to sign on a user using either MyProxy or the AstroGrid accounts service; a client and servlet implementing the IVOA delegation protocol.