The world is going digital. In everything from printing and video to communication, old, analog technologies are giving way to the greater benefits of digital techniques. This change is far more widespread than you may think; computers are of course digital, but, even in India, phones are becoming digital. From digital switching, already in place in major cities, to fully digital phone lines, where large numbers of connections can share the same optical fibre. With digital phone (or more correctly, communication) lines, the distinction between different media such as voice or print dissolves into an emphasis on content. A purely digital conversation can include voice, graphics or any other data as and when needed, without making any difference whatsoever to the communication links or exchanges.

This shift in all forms of communication and information storage is not simply because analog technology is considered obsolete. The major benefit of digital media, apart from its clarity and resistance to deterioration over time, is access and organization. Digital media can be organized; information can be retrieved in millions of ways. Everything ever communicated can be archived, indexed and analyzed.

This last point has been the cause of much agitation among the electronic community who understand the uses it could be put to. While it may help the health care system, for instance, to have on record all interactions with doctors, it could also cause flagrant violations of individual privacy. For instance, if you apply for a job, the company could search all messages written by you for views you may not like them to know. Thankfully, a company can only do this with your public messages to news groups and other public forums. But a government agency may be able to access and automatically analyze your private mail -- in the digital world, Big Brother can get sophisticated data processing computers to watch you.

Of course, governments can record all your phone calls in any case. What makes digital Big Brothers particularly frightening is, firstly, the enormous additional analysis possible if your messages are digital (only fanatics would actually listen to recordings of phone calls -- the only possible method of analyzing analog conversations). Secondly, while no such case has (yet) come up in India, where computer laws are quite archaic, there have been a number of situations in the US where the First Amendment on the right to free expression was ignored for electronic communication. The public in general is not very concerned with freedom in cyberspace (presumably populated by evil heroin-consuming hackers). Unfortunately, violations of privacy and other freedoms now, just set precedents for the future, when the public will be in cyberspace.

The digital solution to this digital problem is transparent encryption of all data. One problem with most encryption methods is the communication of the key from sender to receiver. New methods that make encryption really practical use two keys. If one key is used to encrypt (lock) a message, it can only be decrypted (unlocked) with the other key. Thus one key can be made public (in a phone directory, for example). Anyone can lock a message with my public key, with the assurance that it can only be unlocked with my private key. Of course, no one but me has my private key. This can also be used in reverse, to provide authentication through digital signatures far more secure than a scribble in ink (which can easily be reproduced through a scanner and printer). If I lock a message with my private key, it can only be unlocked by my public key . Consequently, if a message can be successfully unlocked using my public key (which everyone knows), it could only have been locked with my private key. As only I know the latter, this is a signature so secure that it would take a roomful of supercomputers a century to forge.

Public key encryption is becoming increasingly popular. This is not in the interest of the Big Brothers of the world. Next week, I'll discuss recent US initiatives backed by the National Security Agency and FBI to ensure that all encryption used can be broken by these agencies, an omen, perhaps, of the end of freedom at the beginning of the information age.