Long-term security ensures that a protocol remains secure even in the future,
when the adversarial computational power could, potentially, become unlimited.
The notion of universal composability preserves the security of a cryptographic
protocol when it is used in combination with any other protocols, in possibly
complex systems. The area of long-term universally composable secure protocols
has been developed mostly by Müller-Quade and Unruh. Their research conducted
so far has shown the existence of secure long-term UC commitments under general
cryptographic assumptions, thus without having an emphasis on the efficiency of
the protocols designed. Building on their work and using very efficient
zero-knowledge proofs of knowledge from [CL02], this thesis presents a new
long-term universally composable secure commitment protocol that is both
efficient and plausible to use in practice.