It replaces a number of physical identity tools, such as keys to offices and photo-ID's. It also can integrate with Kerberos, so that identity cards will enable e-mail access in the future. This interaction is illustrative of one of the important considerations of electronic privacy designing tools that complement each other. For example, a third tool, secure shell, is used to secure activities between two machines, regardless of user or use. It is particularly useful in the external security perimeter, where tools such as Kerberos do not currently work well.
Tools are long overdue in the area of e-mail privacy protection.
The challenge has been to develop a means that would allow people to exchange keys for encryption while concealing the decryption keys. In the last few years, considerable advances have been made, most notably in the public key infrastructure development, but we are now hampered by a lack of convergence on industry standards. Without those standards there can be no interoperability among users, a critical functionality for general purpose e-mail. The marketplace will eventually identify a solution, but the delay is frustrating. The issues surrounding electronic privacy are compounded by both the volatility and the adaptability of the underlying technologies.