The purpose of this paper is to describe the advantages of using an application layer mechanism based on digital containers for end-to-end security. This approach is independent of the underlying network infrastructure, should scale well to a large number of small transactions (microtransactions) from a large number of consumers and is particularly suited to efficient account based micropayments systems. The paper concludes with a brief description of the SIBIS system, a Java based example implementation of the digital containers architecture, developed during the DTI/EPSRC Link Broadcast project SIBIS. (4 pages)