A Beginner's Guide to the Internet/INTERNET.ISO/text/tutors/privcryp/clipper.sum

Text File | 1996-05-06 | 9.3 KB | 174 lines

Chipping Away at Privacy
by Shari Steele and Daniel J. Weitzner


On April 16, 1993, the Clinton Administration announced a national
standard for encryption.  Under the Administration's Clipper Chip
proposal, voice telephone conversations would be encrypted by chips
built into the telephone units used by the caller and the call
recipient.  Put simply, when a call is made, the two telephones involved
communicate with one another and establish a unique key based on
information contained on each of their chips.  The telephones then use
that key to encrypt and decrypt the conversation.  In this way, anyone
attempting to wiretap the telephone conversation would not be able to
understand what was being said.

However, in order to provide a means for law enforcement officers to
decrypt messages for court-authorized wiretaps, the Administration's
proposal suggested that the keys be held in trust by a third party, who
would only release keys when presented with valid warrants to perform
wiretaps.  To further ensure that the keys would not be too easily
obtained, the Administration's proposal suggested that each key be split
in half, with each half of each key held by a different escrow agent.

The Clipper Chip, which was originally developed by the National
Security Agency (NSA), does offer some measure of privacy to individuals
while providing law enforcement officers with the means to conduct
wiretaps.  However, there are some serious problems with the
government's proposal.  First, the Administration has not established
that the Clipper Chip offers maximum privacy protection.  An encryption
algorithm cannot be trusted unless it can be tested, yet the
Administration proposes to keep the Chip algorithm classified.  What
will give people confidence in the safety of their keys?  Furthermore,
while the use of the key escrow system is one way to balance privacy and
law enforcement needs, the details of this scheme must be explored
publicly before it is adopted.

But before we even begin to address these concerns, we need to start
with one very basic question:  Is the Clipper Chip an attempt by the
federal government to control the use of encryption?  A government-
mandated encryption standard raises profound constitutional questions.

Clipper Mandate Imminent?

So far, the Administration has not declared that use of the Clipper Chip
will be mandatory, but several factors point in that direction:

*     The government has justified keeping the Clipper Chip encryption
    algorithm secret by claiming that it is the only way to ensure
    compliance with the proposed key escrow system.

Many parties have already questioned the need for a secret algorithm,
especially given the existence of robust, public-domain encryption
techniques.  The most common explanation given for use of a secret
algorithm is the need to prevent users from bypassing the key escrow
system proposed along with the Clipper Chip.  If the system is truly
voluntary, then why go to such lengths to ensure compliance with the
escrow procedure?

*     A voluntary system does not solve law enforcement's problems.

The major stated rationale for government intervention in the domestic
encryption arena is to ensure that law enforcement officers have
continued access to criminal communications.  Yet, a voluntary scheme
seems inadequate to meet this goal.  Criminals who seek to avoid
interception and decryption of their communications would simply use
another system, free from escrow provisions.  Unless a government-
proposed encryption scheme is mandatory, it would fail to achieve its
primary law enforcement purpose.  In a voluntary regime, only the law-
abiding would use the escrow system.

Any attempt to mandate a particular cryptographic standard for private
communications, to require that encrypted messages use an escrow system,
or to prohibit the use of specific encryption algorithms would raise
fundamental constitutional questions.  In order to appreciate the
importance of the concerns raised, we must recognize that we are
entering an era in which most of society will rely on encryption to
protect the privacy of their electronic communications.

Constitutional Concerns

If the Administration does intend to mandate the use of a particular
encryption technology, such as the Clipper Chip, and to make the use of
all other encryption technologies illegal, there are serious
constitutional concerns.  A mandatory key escrow system violates the
First, Fourth and Fifth Amendments of the Constitution.

*     A mandatory key escrow system violates the Fourth Amendment
    prohibition against "unreasonable search and seizure."

Wiretapping and other electronic surveillance have always been
recognized as exceptions to the fundamental Fourth Amendment prohibition
against secret searches.  Even with a valid search warrant, law
enforcement agents must "knock and announce" their intent to search a
location before proceeding.  Failure to do so violates the Fourth
Amendment.  Increasing reliance on advanced telecommunications requires
that we re-examine the scope and application of the exception granted to
wiretaps.

Until now, the law of search and seizure has made a sharp distinction
between, on the one hand, seizures of papers and other items in a
person's physical possession and, on the other hand, wiretapping of
electronic communications.  Law enforcement officers must inform an
owner, through the presentation of a valid warrant, before searching
and/or seizing papers or personal effects.  Only in the exceptional case
of wiretapping may law enforcement officers invade a person's privacy
without simultaneously informing that person.

Today, the distinction between storage of information and communication
of information is not so clear.  Instantaneous access to encryption
keys, without notice to the communicating parties, may well constitute a
secret search if law enforcement officers seize the "papers" (now in
electronic form) of a virtual corporation or an individual.

*     A key escrow system forces a mass waiver of all users' Fifth
    Amendment rights against self-incrimination.

The Fifth Amendment protects individuals facing criminal charges from
having to reveal information that might incriminate them at trial.  So
far, no court has determined whether or not the Fifth Amendment allows a
defendant to refuse to disclose his or her cryptographic key.  As
society and technology have changed, courts and legislatures have
gradually adapted fundamental constitutional rights to new
circumstances.  Such decisions require careful, deliberate action.  But
the existence of a key escrow system would have the effect of waiving
this right for every person who used the system in a single step.

*     Prohibition against use of certain cryptographic techniques is a
    content-based restriction which violates individuals' right to
    free speech guaranteed under the First Amendment.

Prohibiting the use of a particular form of cryptography for the express
purpose of making communication intelligible to law enforcement officers
is akin to prohibiting someone from speaking a language not understood
by law enforcement officers.  And, while courts have upheld "time, place
and manner" restrictions, such as laws that limit the volume of speakers
from interfering with surrounding activities and confine demonstrators
to certain physical areas, no court has ever upheld an outright ban on
the use of a particular language.  Moreover, in order for a time, place
and manner restriction to be a valid restraint on speech, a government
must show that it is the "least restrictive means" of accomplishing the
government's goal.  It is precisely this question -- the availability of
alternatives that could solve law enforcement's actual problems -- that
we must be able to explore before we can promote a solution such as key
escrow.

Digital Privacy and Security Working Group

On May 14, 1993, the Digital Privacy and Security Working Group sent a
list of over 100 questions to President Clinton, expressing the Group's
concerns and asking that a public dialogue be initiated to discuss the
issue further.  The Digital Privacy and Security Working Group is a
coalition of over 50 organizations -- from computer software and
hardware firms, to telecommunications companies and energy companies, to
the American Civil Liberties Union and the Electronic Frontier
Foundation -- that was formed over a decade ago and is chaired by EFF's
Executive Director, Jerry Berman.  The Working Group identified several
other aspects of the Administration's encryption proposal that warranted
further discussion, including:

*     the security of the key escrow system;
*     the advisability of a government-developed and classified
    algorithm;
*     the Clipper Chip's practicality and commercial acceptability;
*     the effect of the proposal on American competitiveness and the
    balance of trade;
*     possible implications for the development of digital
    communications; and,
*     the effect on the right to privacy and other constitutional
    rights.

The Administration has agreed to slow down the process in order to
enable a deliberate government policy on encryption to be developed
before any one encryption technology is embraced.