sentences:  The Signed and Encrypted Email Over The Internet demonstration has shown that organizations can collaborate effectively using secure email.Previous barriers to adoption were overcome, including the use of a PKI bridge to provide a scalable public key infrastructure (PKI) and the use of network security guards checking encrypted content passing in and out of corporate network boundaries to avoid encryption being used to hide malware introduction and information leakage.Transport layer encryption using STARTTLS must be set up by the receiving organization.