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CPSR Clipper Fact Sheet

Clipper Fact Sheet from 1994

This Fact Sheet was provided by CPSR, and was last updated 1 May 1994.

What is Clipper? What is Capstone?

Clipper is an electronic micro-chip designed by the U.S. Government for use in new digital telephones. It encrypts phone calls, making them unintelligible to most others, such as competitors or foreign agents.

Capstone is a version of the Clipper chip designed for use in personal computers and digital appliances instead of telephones. Both Clipper and Capstone use the "Skip-Jack" encryption system, which may become the new U.S. Government standard for encryption.

Why is this of interest to me?

Encryption offers you privacy, protection against being recorded or monitored.

Today, most phones are easily intercepted and recorded by anyone who knows how, using tools available in many electronics stores.

Today's cordless and cellular telephones, which are not digital, are especially susceptible to unwanted interception. Their calls can be received with scanners from electronics stores, and even with old TV sets! They are much less private than the hard-wired phones in your home and office.

What is encryption? Is it different from scrambling?

Scrambling makes a phone call unintelligible to anyone who doesn't have a descrambler, but anyone with a descrambler can understand the conversation.

Encryption uses a special "key", like a combination lock where you can pick your own combination, to secure the conversation, making it unintelligible to taps, monitors, and in recordings. Only someone who knows the combination (the "key") can decipher the encrypted conversation. Simply having the deciphering box isn't enough; an eavesdropper has to know the combination, too.

What's the issue with Clipper? What's wrong with it?

Clipper has a "back door" built into it which allows U.S. Intelligence and Law Enforcement agencies to listen in without knowing the combination (the secret "key").

It's something like those combination locks with key holes in the back that children use to protect the contents of their school lockers. The students use their combinations to open their locks, but the teachers can use the master key to open the lock without knowing the combination. With Clipper, citizens may keep secrets from each other, but not from the Government.

Law enforcement isn't supposed to decipher conversations without a Court order (a warrant). To provide some assurances that court orders will be used, the government has proposed requiring two different agencies of the government (called "key escrow agents") to agree before a law enforcement agency can decipher the conversation. However, there are ways to abuse this system, and there's no way to know when it's being abused.

Protection from U.S. intelligence agencies is not mentioned in the government Clipper proposals.

Since foreign customers won't want U.S. intelligence listening in, Clipper products will not be acceptable in foreign markets. U.S. manufacturers will have to make separate products for domestic and international markets, reducing U.S. competitiveness.

I've heard that with Clipper the government will be able to know everything I say, and everything that's in my computer. Is that true?

Clipper isn't a little radio transmitter. The government will still have to tap your phone line, or monitor your cellular calls, or sieze your computer (with a search warrant) to be able to know what you're saying or what you've got stored in your computer.

Will the government make me put Clipper in all my telephones?

No. The government is quite happy for you to continue to use your existing analog phone which has no privacy protection at all.

Clipper is expected to become a government standard. When the government buys new phones, it will buy ones with Clipper chips inside.

Clipper only works in digital phones, like the new digital cellular phones and digital extension phones used in many modern offices.

When ISDN phones are available for use in your home, then if you want to buy a phone with an encryption or "security" feature, Clipper might be the only choice available.

Are there alternatives to Clipper?

Yes, there are several encryption systems that don't have Clipper's "back door". The older U.S. Data Encryption Standard (DES), the International Data Encryption Algorithm (IDEA), and the patented RSA Public Key encryption algorithms are all suitable for use in alternative secure telephones.

Why aren't secure phones available today?

Today, "security" telephones with encryption are rare and expensive because the government has made it difficult and expensive to sell products that use encryption. To make encryption products, companies must register as arms merchants (just like manufacturers of tanks). To export encryption products, companies must obtain special munitions export licenses from the Department of state, just as if they were selling missiles. These licenses are often denied.

What is CPSR's position on Clipper?

We oppose Clipper. We support strong encryption standards, developed openly.

We oppose having the next Data Encryption Standard be a classified military standard, not available for open scrutiny.

We oppose having standards for civilian privacy be developed by a super-secret military intelligence agency, in apparent violation of the Computer Security Act of 1987.

We support freeing U.S. industry to develop good encryption products and standards, and to sell them internationally.

We support the right of the sovereign citizens of the U.S. to use the best methods available to protect their own privacy.

What can I do?

Boycott Clipper phones and computers. Buy products that feature other encryption systems, such as DES, IDEA, or RSA. Tell your computer and telephone suppliers that Clipper isn't good enough for your privacy needs.

Write your representatives in Washington, and the President. Tell them you support lifting the controls on manufacture and export of encryption products. Tell them you're concerned about Clipper's effect on your privacy, and on U.S. businesses competing internationally. Tell them how this issue will affect your vote.

	Computer Professionals for Social Responsibility
P.O. Box 717
Palo Alto, CA 94302
Ph: (415) 322-3778
Email: cpsr @

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