Malte Timmermann, a technical architect at Sun Microsystems, gave a presentation on digital signatures in OpenOffice.org. He discussed why digital signatures are used for authentication, authorization, and verifying document integrity. He then explained the technology behind digital signatures, including hash values, encryption algorithms, and public key certificates. Finally, he covered OpenOffice.org's implementation of digital signatures using XML DSIG and its security framework, and demonstrated features like adding and verifying signatures.