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July 15, 1997
CAMBRIDGE, MASS.—Computer encryption, a necessity for electronic commerce and secure communications, is about to pop up everywhere. The technical questions have been resolved to the point where the average user can feel safe, and commercial solutions are under preparation. The only question that remains is law enforcement agencies’ desire to have potential access to all communications.
Many Internet users suspect, in fact, that if the market had its way, we’d already have encryption so strong that nobody could crack our secret keys for thousands of years, and as simple to use as checking a box. But national governments frown on encryption. The barriers they’ve erected, and the threat of barriers, create a chilling effect on the companies that would provide encryption.
Without encryption, there are simply too many ways that mail is open to the malicious or mischievous. Your mail can pass through a dozen systems and be read by a system administrator on any of them; it can also be preserved by back-ups for future snoopers. Intruders can place a packet sniffer on the network within your facility or tap your phone.
But the government is not ready for the average citizen to send messages that outsiders can’t read. Law enforcement officers are used to wiretapping phones and opening mail, and they want the same access to electronic communications.
The International Traffic in Arms Regulations have been enforced by the Department of Commerce for decades, preventing the export of encryption products that have long enough keys to resist cracking for a reasonable amount of time. In June, on practically the same day that a District Judge ruled the regulations a violation of Constitutional protections on free speech, Senators John McCain and Bob Kerrey introduced them for the first time in a bill before Congress, the Orwellian-named “Secure Public Networks Act” (S. 909).
Meanwhile, the Communications Assistance for Law Enforcement Act of 1994 required all cellular and wireless telephones to use encryption that law enforcement officers can crack. The FBI has stretched the law farther by trying to include circuitry in every phone that tells government snoops where the caller is.
But the most intrusive burden that the U.S. government has tried to place on encryption is the “Trusted Third Party” or “key recovery” scheme. To understand how it weakens the security of all telephone and network users, one must learn a bit about how modern encryption works.
Most computerized encryption systems no longer employ the obvious strategy of sharing a single key between sender and recipient. It would be too hard to pass your key to everybody who needs it, while keeping it out of the hands of malicious users—how, for instance, would you safely convey your key to manufacturers you’re buying from in India?
Instead, encryption uses a public key system. You create a pair of keys that work together. The first is broadcast to the general public, and the second is carefully hidden away, off the network.
Still, a danger remains. Someone else could claim to be you and could proffer his public key as yours. This is where the concept of Trusted Third Parties was invented. Like banks, they deal with large groups of people and are widely trusted. The TTP can hold your public key and guarantee to potential correspondents that it really comes from you.
The Clinton Administration latched onto the TTP idea, but they significantly altered its role. Instead of public keys, the proposals make people give the TTP their private keys. The government can then obtain the private keys and read email or listen to digital telephone companies without the correspondents ever knowing about it. This untrustworthy scheme was incorporated into the McCain-Kerrey bill.
The first versions of the Administration TTP proposal, called the “Clipper chip,” included checks and balances like those now employed for telephone wiretapping. A judge would have to issue a warrant for the key. This stipulation can make an important difference, as we see in recent rulings by a Massachusetts judge that evidence obtained under wiretap against Boston-area mobsters is illegal.
Later versions of the proposal, coming from Administration on March 12 and McCain-Kerrey in June, removed these safeguards. The current version of McCain-Kerrey has restored them, but the ease with which digital snooping can be conducted on large groups of people still worries those of us who remember COINTELPRO and Watergate.
U.S. policy on the Internet inevitably determines that of other countries too. Ministers in both Britain and Germany have recommended key recovery systems like McCain-Kerrey, while France and Russia have outlawed any form of encryption that their governments can’t crack. The public has to decide how safe they want to be, and how much power they are willing to give the government to facilitate the fight against crime. The Clinton proposals and McCain-Kerrey are much too much.
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