A number of applications have emerged over recent years that use datagram transport. These applications include real time video conferencing, Internet telephony, and online games such as Quake and StarCraft. These applications are all delay sensitive and use unreliable datagram transport. Applications that are based on reliable transport can be secured using TLS, but no compelling alternative exists for securing datagram based applications. In this paper we present DTLS, a datagram capable version of TLS. DTLS is extremely similar to TLS and therefore allows reuse of pre-existing protocol infrastructure. Our experimental results show that DTLS adds minimal overhead to a previously non-DTLS capable application.