Zero-install browserbased encryption and crypto timestamping in FileSender. At SURFnet and AARNet, work is underway to build install-free browser- based plugin modules for FileSender (the NREN-built web-based very large file transfer solution), one that handles on-the-fly encryption, and another that handles cryptographic timestamping. A user who is interested in testing out the capabilities offered by these plugins can do so straight away from the main FileSender interface; no further installation is needed. This talk explores use cases, development and caveats, and a few case studies.