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D.Denning Reply
Here is Dorothy Denning's reply to my response to her Newsday article. The
shocking features are that she does not seem able to differentiate legality
from morality, and doesn't seem to believe that law should flow from a popular
majority, but from the state. Sure sounds like she wants a police state to me.
Steve Blasingame
[email protected]
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From daemon Mon Feb 28 09:06:58 1994
Date: Mon Feb 28 11:25:34 -0500 1994
From: netcomsv!chair.cosc.georgetown.edu!denning
Subject: Re: Newsday Editorial
To: internet!attmail!zontar!bsteve
Reply-To: netcomsv!chair.cosc.georgetown.edu!denning (Dorothy Denning)
Thanks for your comments. I have tried to address the law enforcement
issues you raised in a more thoughtful way in the attached.
Dorothy Denning
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Encryption and Law Enforcement
Dorothy E. Denning
Georgetown University
February 21, 1994
Summary
Although encryption can protect information from illegal access, it can
also interfere with the lawful interception of communications by
government officials. The goal of this report is to describe the
effect of encryption technology and the government's new Escrowed
Encryption Standard [EES] on law enforcement, mainly from the
perspective of law enforcement. The information presented here was
obtained from public documents and testimonials by law enforcement
officials, from private conversations with people in the FBI and other
law enforcement agencies, and from comments I received by people in law
enforcement on an earlier version of this report. Some of this
research was performed in conjunction with my earlier study of the
FBI's proposal on Digital Telephony [DT, Denning].
The following summarizes the key points, which are discussed in greater
depth in the sections that follow:
1. The need for wiretaps: Court-authorized interception of
communications is essential for preventing and solving many
serious and often violent crimes. Electronic surveillance not
only provides information that often cannot be obtained by other
means, but it yields evidence that is considerably more reliable
and probative than that obtained by most other methods of
investigation. No other investigative method can take its
place.
2. The threat of encryption to lawful surveillance: Because
encryption can make communications immune from lawful
interception, it threatens a key law enforcement tool. The
proliferation of high quality, portable, easy-to-use, and
affordable encryption could be harmful to society if law
enforcement does not have the means to decrypt lawfully
intercepted communications. Although encryption of stored files
is also of concern, 99% of the issue is telephone communications
(voice, fax, and data).
3. Digital Telephony: Encryption is not the only threat to lawful
electronic surveillance. Advances in telecommunications also
threaten the ability of law enforcement to conduct authorized
interceptions.
4. Encryption policy and the EES: The government's Escrowed
Encryption Standard offers a balanced solution to the encryption
problem that takes into account the equities of public safety,
effective law enforcement, and national security along with those
of privacy, security, and industry success. The technology and
accompanying procedures provide strong encryption and a high
level of security, while accommodating the need for real-time or
near real-time decryption of intercepted communications. The
program is the best known solution, at least for the intended
initial application, mainly voice, fax, and data encryption over
the public switched network.
5. Criminal use of Non-EES Encryption: Although some criminals may
seek to use other forms of encryption, the escrowed encryption
standard may succeed and become ubiquitous as the chief form of
encryption, making it much harder for criminals to evade
interceptions by using non-standard, non-interoperable
encryption.
6. International problem: The impact of encryption on law
enforcement is an international problem. The U.S. government
exercised strong leadership by recognizing the problem and
developing a solution before it becomes serious.
1. The Need for Wiretaps
Law enforcement views court-authorized interception of communications
as essential for preventing and solving many serious and often violent
crimes, including terrorism, organized crime, drugs, kidnaping, major
white collar crime brought against the government, and political
corruption [DT, DT Cases, Kallstrom]. In testimony before the Computer
Systems Security and Privacy Board, James Kallstrom, former Chief of
the FBI's Engineering Section, estimated that wiretaps are used in
excess of 90% of all cases involving terrorism, often with the result
of preventing a terrorist act. For example, in a Chicago case
code-named RUKBOM, the FBI successfully prevented the El Rukn street
gang, which was acting on behalf of the Libyan government, from
shooting down a commercial airliner using a stolen military weapons
system [Kallstrom, DT Cases]. Examples of other terrorist attacks
successfully prevented with the help of electronic surveillance include
the bombing of a foreign consulate in the U.S. and a rocket attack
against a U.S. ally.
Electronic surveillance is used against organized crime, widespread
fraud, bribery, and extortion. It was used to help solve a case
involving corruption associated with organized crime control of the
International Longshoremen's Union, which cost the citizens of New York
city 10-12 cents on every dollar spent on consumer items coming through
the port of New York, and to help solve another case involving
organized crime control over the construction trade of New York City,
which had led to 3-5% of all construction contracts being escalated by
that percentage [Kallstrom]. Evidence obtained from electronic
surveillance in a case involving the Concrete and Cement Workers Union
prevented an economic loss to the public of $585 million [DT Cases].
According to the FBI, the hierarchy of La Cosa Nostra has been
neutralized or destabilized through the use of electronic surveillance,
and thirty odd years of successes would be reversed if the ability to
conduct court-authorized electronic surveillance was lost.
Almost two thirds of all court orders for electronic surveillance are
used to fight the war on drugs, and electronic surveillance has been
critical in identifying and then dismantling major drug trafficking
organizations. In an operation code named "PIZZA CONNECTION," an FBI
international investigation into the importation and distribution of
$1.6 billion worth of heroin by the Sicilian Mafia and La Cosa Nostra
resulted in the indictment of 57 high-level drug traffickers in the
U.S. and 5 in Italy [DT Cases]. The FBI estimates that the war on
drugs and its continuing legacy of violent street crime would be
substantially, if not totally, lost if law enforcement were to lose its
capability for electronic surveillance.
Wiretaps are used for cases involving murders and kidnapings. As the
result of wiretaps, sufficient evidence was obtained to arrest and
convict a serial-murderer who had been operating for three to four
years, and to locate and subsequently convict two other persons who had
been involved with the murders [DT Cases]. By intercepting voice, fax,
and communications on a local bulletin board system, the FBI prevented
the proposed kidnaping and murder of a young child for the purpose of
making a "snuff murder" film [Kallstrom]. Through wiretaps, the FBI
prevented a group from bombing a man's house and killing him and his
family [Kallstrom].
Electronic surveillance has been used to investigate aggravated
governmental fraud and corruption. A recent military-procurement fraud
case ("Ill-Wind") involving persons in the Department of Defense and
defense contractors has so far led to 64 convictions and about $260
million in fines, restitutions, and recoveries ordered. In another
case, U.S.District Court Judge Robert Collins was convicted of
soliciting and accepting bribes [DT Cases]. John Kaye, Prosecutor for
Monmouth County, New Jersey, reported that almost every police officer
indicted in his county has been indicted because of a wiretap [Kaye].
In the decade from 1982 to 1991, state and federal agencies were
granted 7,467 court orders for interceptions under Title III of the
Omnibus Crime Control and Safe Streets Act and equivalent state
statutes. At the end of 1991, these had led to 35,851 arrests and
19,259 convictions. Convictions resulting from interceptions conducted
in the last few years are still accumulating, as trials regarding those
subjects are held. Because the number of arrests associated with
wiretaps is a small fraction of all arrests each year, some people have
questioned whether wiretaps are necessary or worthwhile given the
availability of other investigative techniques.
By law, wiretapping cannot be used if other methods of investigation
could reasonably be used instead. Such normal investigative methods
usually include visual surveillance, interviewing subjects, the use of
informers, telephone record analysis, and Dialed Number Recorders
(DNRs). However, these techniques often have limited impact on an
investigation. Continuous surveillance by police can create suspicion
and therefore be hazardous; further, it cannot disclose the contents of
telephone conversations. Questioning identified suspects or executing
search warrants at their residence can substantially jeopardize an
investigation before the full scope of the operation is revealed, and
information can be lost through interpretation. Informants are useful
and sought out by police, but the information they provide does not
always reveal all of the players or the extent of an operation, and
great care must be taken to ensure that the informants are protected.
Moreover, because informants are often criminals themselves, they may
not be believed in court. Telephone record analysis and DNRs are
helpful, but do not reveal the contents of conversations or the
identities of parties. Other methods of investigation that may be
tried include undercover operations and stings. But while effective in
some cases, undercover operations are difficult and dangerous, and
stings do not always work. Law enforcers claim that no other method
can take the place of wiretaps [Kallstrom].
Each court order must provide evidence for the need to wiretap by
demonstrating that normal investigative procedures have been tried and
have failed or reasonably appear unlikely to succeed or would be too
dangerous [USC 18, DDKM]. This does not mean that the other methods
are not used in those cases, as indeed they are, but only that they are
inadequate to successfully investigate and prosecute the cases.
Wiretaps not only provide information that cannot be obtained by other
means, but yield evidence that is considerably more reliable and
probative than that obtained by most other methods of investigation. A
wiretap is also less dangerous than sending in a civilian informant or
undercover agent who is wired since the risk of discovery puts that
person's life in jeopardy. Finally, a wiretap may be less invasive of
privacy than placing a bug in a subject's home or using an undercover
agent to establish an intimate relationship with the subject.
Although the number of arrests from wiretaps is relatively small
compared to the total of all arrests, those criminals that are arrested
and convicted with the aid of wiretaps are often the leaders of major
organized crime, drug trafficking, and terrorist groups. In reviewing
a proposal for a wiretap, law enforcement agencies determine whether
the subjects of the proposed interception are worthy targets of
investigation and whether the interception is worth doing.
The law enforcement community views electronic surveillance as
essential to effective law enforcement, and law enforcement as
essential not only to public safety and our economic well-being, but to
a free society. In his remarks at the Computer Ethics Conference, Alan
McDonald of the FBI summed it up: "We have been fortunate as a society
to enjoy unparalleled freedom. It has resulted because we live under a
compact of ordered liberty. One need only consider the number of
countries where law enforcement is ineffective and where the violence
and corruption of organized crime reign to see true diminishments of
freedom, liberty, and personal privacy" [McDonald].
2. The Threat of Encryption to Lawful Surveillance
Encryption has been available to criminals for a long time. Until
recently, however, voice encryptors were extremely bulky and the
quality of the voice low, so criminals who tried encryption would
typically cease using it [Kallstrom]. But recent advances in
encryption technology are leading to products such as the AT&T 3600
Telephone Security Device that are small, portable, easy-to-use,
affordable, and have high quality audio. Law enforcers expect that
criminals will flock to such devices, not only to hide their
communications from the government, but to safeguard them from their
competitors [Kallstrom, Meeks]. The effect could be that criminals are
able to make their communications immune from government search and
seizure even under probable cause of criminal activity.
The proliferation of such encryption products ultimately could be
harmful to society if government officials do not have the means to
decrypt lawfully intercepted communications, at least in most cases.
On behalf of the National District Attorney's Association, President
Robert Macy writes: "In an increasingly dangerous world, law
enforcement cannot afford to be blindfolded by advanced technologies
including encryption devices" [Macy]. Roy Kime, Legislative Counsel
for the International Association of Chiefs of Police, makes the
analogy that people in law enforcement are being "outgunned" by the
criminals with respect to advances in technology [Kime]. In testimony
before Congress, Donald Delaney, Senior Investigator with the New York
State Police, said he believed that if we adopted an encryption
standard that did not permit lawful intercepts, we would have havoc in
the United States [Delaney]. Although there are no "dead bodies" as
yet, Kallstrom believes there will be a "horror show" if the encryption
that proliferates in the market does not factor in an equity for law
enforcement [Kallstrom].
Criminals can use encryption to conceal stored information as well as
communications. In a child pornography case on the West coast,
encrypted data files have slowed down the investigation of a large
international ring dealing with child pornography and the possible
smuggling of children [Kallstrom]. However, although law enforcement
is concerned about the use of encryption to conceal computer files,
their primary concern is with communications, particularly telephone
conversations. This is because intercepts play a much more important
role in investigations than documents. Real-time intercepts pick up
the criminal dialogue, the plotting and planning that glues crimes
together. By revealing conversations about possible future activities,
wiretaps also may be used to prevent crimes from occurring. Thus, while
being able to decrypt files is valuable, 99% of the issue today is
telephone conversations [Kallstrom]. In addition, while communications
over high speed computer networks are expected to become an issue, the
primary concern today is with voice, fax, and data over the public
switched network (telephone system).
3. Digital Telephony
Encryption is not law enforcement's only concern about wiretaps. They
are also concerned about changes in telecommunications technologies.
Many of the new digital-based technologies and services such as ISDN,
fiber optic transmissions, and the increasing number of mobile
telecommunication networks and architectures cannot be tapped using the
traditional methods used to intercept analogue voice communications
carried over copper wire. In addition, increases in transmission speed
have made interceptions more difficult. Although it is technically
feasible to intercept the new communications, not all systems have been
designed or equipped to meet the intercept requirements of law
enforcement. According to the FBI, numerous court orders have not been
sought, executed, or fully carried out because of technological
problems. To address these problems, the Department of Justice
proposed Digital Telephony legislation [DT] that would require service
providers and operators to meet their statutory assistance requirements
by maintaining the capability to intercept particular communications.
So far, the proposal has not been introduced in Congress.
4. Encryption Policy and the EES
Law enforcement seeks an encryption policy that takes into account the
equities of public safety, effective law enforcement, and national
security along with those of privacy, security, and industry success
[Kallstrom]. They support the use of encryption by law abiding
citizens and organizations to protect sensitive information, and
recognize the importance of encryption to safeguarding information
assets [Settle]. They generally favor strong encryption over weak or
"dumbed down" encryption [Kallstrom]. To implement lawful
interceptions of encrypted communications, they need a real-time or
near real-time decryption capability in order to keep up with the
traffic and prevent potential acts of violence. Since there can be
hundreds of calls a day on a tapped line, any solution that imposes a
high overhead per call is impractical.
These requirements for strong encryption and near real-time decryption
led to the Escrowed Encryption Standard [EES] and its related key
escrow system. Upon receiving a chip's unique key components from the
two escrow agents, law enforcers can readily decrypt all conversations
encrypted with the chip until the wiretap terminates, at which time all
chip-related keys are destroyed. The escrow agents need not get
involved in the decryption of each conversation, which would be overly
cumbersome.
Law enforcers consider the EES to be the best known approach for
addressing the dual need for secure communications and court-ordered
access, at least for the intended initial application, namely voice,
fax, and data encryption of telephone communications transmitted over
the public switched network. The EES will significantly enhance
communications security by making strong encryption available in a way
that makes illegal wiretaps virtually impossible, while permitting
those that are lawfully authorized. The key escrow mechanisms and
procedures are being designed to provide a high level of protection for
keys and to protect against compromises or abuses of keys, thereby
assuring that no person or entity, including government, can improperly
access one's EES communications. Although there is no evidence of
widespread abuse of wiretaps by law enforcement officials, the EES will
effectively thwart any potential abuse, thereby providing greater
protection from illegal government wiretaps than currently exists.
The Presidential Decision Directive [PDD] on escrowed encryption is
viewed as offering a balanced solution to the encryption problem that
is consistent with basic tenets found in the Constitution and in the
Bill of Rights, which does not grant an absolute right to privacy, but
rather seeks to balance individual privacy with the need to protect
society as a whole [McDonald]. William A. Bayse, Chief Scientist of
the FBI, observed: "It is well recognized that Anglo-American law has
historically balanced the personal privacy of the individual with the
legitimate needs of Government. ... As can be seen from a review of the
Fourth Amendment to the U.S. Constitution ..., an individual's privacy
rights are not absolute, and they give way to more compelling
Governmental rights when criminality is demonstrated or suspected."
[Bayse]. Similarly, Alan McDonald noted "... the dictum of the Bill of
Rights, and the Fourth Amendment in particular, is a balance between
individual liberty and privacy and the legitimate need of Government to
protect society as a whole -- a balance to prevent the tyranny of
absolutist Government and the tyranny of lawlessness and anarchy. ...
The electronic surveillance statutes, like the Fourth Amendment, are
founded on the concept of balancing fundamental individual and
governmental interests -- personal privacy and the public safety. ...
Encryption technology creates no legal rights under our Constitution,
the Fourth Amendment, or under our electronic surveillance statutes"
[McDonald].
5. Criminal Use of Non-EES Encryption
Some people have argued that criminals will not use EES, but rather
will use encryption methods that defeat law enforcement. While
acknowledging that some criminals may use other means, law enforcers
assume most vendors will not manufacture an encryption device unless
they perceive a large, legal market [Kallstrom]. The hope is that the
EES, or some other approach that takes into account the law enforcement
equities, will proliferate in the legitimate encryption market in this
country and become transparent, thereby cutting down on the
availability and use of encryption that does not include the law
enforcement equities [Kallstrom].
There is some evidence that through market forces and government
purchasing power, the EES may become the de facto national standard for
telephone encryption. When AT&T announced its 3600 Telephone Security
Device in Fall 1992, the device used a DES chip for encryption, and did
not include a capability for law enforcement access. Priced at $1200,
it would have been attractive to criminals, and could have led to the
promulgation of encryption technology that would have posed a major
threat to law enforcement. However, when the government announced the
key escrow initiative on April 16, 1993, AT&T simultaneously announced
that the TSD would use instead the new Mykotronx MYK-78 chip, aka
"Clipper", which uses the EES. The government ordered several thousand
of the modified devices.
Since EES products can be exported to most places, there is an
additional incentive for vendors to incorporate the EES into their
products rather than, say, the DES, which is subject to stricter export
controls. However, there are other factors relating to the nature of
the technology and to public acceptance that could interfere with
widespread adoption of EES by vendors.
Criminals need to talk with many people outside their circle in order
to carry out their activities, for example to rent or purchase needed
goods and services. To conduct those conversations, which may be
incriminating, they will either need to use an encryption method
identical to that used by the other parties or else forego encryption
entirely. Assuming EES dominates in the legitimate market, criminals
may prefer to use it over communicating in the clear since the EES will
at least protect them from their competitors. Criminals are often
sloppy in protecting their conversations from law enforcement, making
incriminating statements over the phone while acknowledging their
phones may be tapped.
Even if criminals do not use the EES, the government's objective of
making strong encryption available to the public in a way that is not
harmful to society will be achieved. Criminals will not be able to
take advantage of the strong algorithm to thwart law enforcement.
Since it is extremely difficult to develop high quality, strong
encryption products, law enforcement may be able to access many non-EES
encrypted criminal communications.
6. An International Problem
The impact of encryption on effective law enforcement is an
international problem, and U.S. law enforcers have observed other
countries looking at solutions based on "dumbing down" the encryption
or on key escrow. The U.S. government exercised strong leadership by
recognizing the problem and developing a solution before it became
serious. While the U.S. solution will not necessarily provide an
international solution, it as a starting point for solving a global
problem.
References
[Bayse] Bayse, William A., Written statement presented at Part I of
the Forum on Rights and Responsibilities of Participants in
Networked Communities, panel on Privacy and Proprietary
Interests, Computer Science and Telecommunications Board,
National Research Council, October 1992.
[Delaney] Delaney, Donald P., statement in "Hearings before the
Subcommittee on Telecommunications and Finance of the
Committee on Energy and Commerce, House of
Representatives," June 9, 1993; Serial No. 103-53, pp.
163-164.
[DDKM] Delaney, Donald P; Denning, Dorothy E.; Kaye, John; and
McDonald, Alan R., "Wiretap Laws and Procedures: What
Happens When the Government Taps a Line," September 23,
1993; available from Georgetown University, Department of
Computer Science, Washington DC, or by anonymous ftp from
cpsr.org as cpsr/privacy/communications/wiretap/
denning_wiretap_procedure.txt.
[EES] "Escrowed Encryption Standard," Federal Information
Processing Standard Publication (FIPS PUB) 185, National
Institute for Standards and Technology, 1994.
[Denning] Denning, D. E., "To Tap or Not to Tap," Comm. of the ACM,
Vol. 36, No. 3, March 1993, pp. 25-35, 42-44.
[DT] "Digital Telephony," U.S. Department of Justice, Federal
Bureau of Investigation.
[DT Cases] "Digital Telephony Case Examples," distributed with
press packet for Presidential Decision Directive on "Public
Encryption Management."
[Kallstrom] Kallstrom, James K., Presentation at the Computer System
Security and Privacy Advisory Board Meeting, National
Institute of Standards and Technology, July 29, 1993.
[Kaye] Kaye, John, Presentation at the Computer System Security
and Privacy Advisory Board Meeting, National Institute of
Standards and Technology, July 29, 1993.
[Kime] Kime, Roy, Presentation at the Computer System Security and
Privacy Advisory Board Meeting, National Institute of
Standards and Technology, July 29, 1993.
[Macy] Macy, Robert H., Letter submitted to the Computer System
Security and Privacy Advisory Board on behalf of the
National District Attorneys Association for June 2-4
Meeting, May 27, 1993.
[McDonald] McDonald, Alan R., Written statement presented at 2nd
National Computer Ethics Conference, April 29, 1993.
[Meeks] Meeks, Bud, Presentation at the Computer System Security
and Privacy Advisory Board Meeting, National Institute of
Standards and Technology, July 29, 1993.
[PDD] Presidential Decision Directive on "Public Encryption
Management," and Statement by the Press Secretary, The
White House, April 16, 1993.
[Settle] Settle, James C., Presentation at INFOEXPO '93, Information
Security and Virus Prevention Conference and Exhibition,
National Computer Security Association, June 11, 1993.
[USC 18] Title 18 USC, Sections 2510-2521. (These sections codify
Title III of the Omnibus Crime Control and Safe Streets Act
of 1968, as amended by the Electronic Communications
Privacy Act of 1986.)
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