[117569] in Cypherpunks
IP: Net Code-Cracking: Need for Stronger Locks
daemon@ATHENA.MIT.EDU (Robert Hettinga)
Mon Sep 6 11:48:12 1999
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From: believer@telepath.com
Date: Mon, 06 Sep 1999 03:12:52 -0500
To: ignition-point@precision-d.com
Subject: IP: Net Code-Cracking: Need for Stronger Locks
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Source: New York Times
http://www.nytimes.com/library/tech/99/09/biztech/articles/06code.html
September 6, 1999
NEWS ANALYSIS
Internet Code-Cracking Project Shows Need for Stronger Locks
By SARA ROBINSON
When an international team of researchers demonstrated recently
that they could break the standard lock that protects financial
transactions over the Internet, they sent a clear message to the
e-commerce community: Now is the time to get stronger locks.
The researchers' demonstration showed only that locks of a certain
strength, known as RSA 512-bit encryption codes, could be broken. But
it is precisely that code strength that is used for a number of the financial
transactions with e-commerce sites on the Internet.
The demonstration, part of a challenge
sponsored by the company that invented the
RSA system, required computing resources
typically available only to governments or big
corporations. But the computing power was
insignificant compared with other code-cracking
efforts, said Arjen Lenstra, one of the main
researchers for the seven-month effort.
Moore's Law, which says that computing power roughly doubles every
18 months, suggests that such power may someday be available to
individuals. Even more important, improvements in the techniques used
for factoring large numbers -- a process that enables RSA codes to be
cracked -- may dramatically reduce the computational resources
required.
"As soon as you break something, then within a relatively short time,
many people will be able to break it," said Lenstra, a computer scientist
at Citicorp. "I have no doubt that within a few years it will be more or
less a triviality."
The government has long restricted the export of strong encryption, citing
concerns that it might be used to conceal messages or transactions by
terrorists or drug traffickers. Over the last year, because of market
pressures, it has relaxed those standards somewhat for encryption
products related to e-commerce, but the 512-bit standard remains
prevalent among Web sites.
"The level of security has been 512 for so long that it's still a part of the
infrastructure," said David Wagner, a computer security researcher at the
University of California at Berkeley. "It will be several years before this
changes."
The current export-control
policy, which requires
companies seeking to export
encryption products to go
through a one-time review, is so
complex that many encryption
experts, secure-software
manufacturers and government
officials interviewed for this
article could not say how it
applies to RSA products.
"The problem with the
encryption policy is that the devil is in the details," said Roszel Thomsen,
a lawyer specializing in export controls at Thomsen & Burke, a law firm
in Washington. "The policy has been drafted with a degree of ambiguity
that is calculated to allow the regulators to make up their minds case by
case."
>From the government's perspective, "complicated is in the eye of the
beholder," said William Reinsch, the under secretary of commerce for
export administration. "We're trying to pursue a balanced policy. I
believe that the critics of our policy are those who do not believe that
national security and law enforcement concerns are as important as we
believe they are."
Many security experts believe that encryption export standards have
been tied to levels decipherable by the National Security Agency, whose
think tanks -- staffed with mathematicians -- devote enormous resources
to code cracking.
"Organizations could already be breaking e-commerce keys regularly,
and just not telling anyone," said Bruce Schneier, chief technology officer
of Counterpane Internet Security Inc., a consulting company based in
San Jose, Calif. "I think there's a 100 percent chance the NSA does this
already They would be remiss in their charter if they didn't."
The researchers' actual feat was to factor a 155-digit number into its two
component prime factors. The inherent hardness of factoring, an
immensely difficult and time-consuming task for even the most powerful
computers, provides the security for RSA. Factoring a certain large
number associated with an RSA key enables that key to be cracked.
Named for its founders -- Ronald Rivest of the Massachusetts Institute of
Technology, Adi Shamir of the Weizmann Institute of Science in
Rehovoth, Israel, and Leonard Adleman of the University of Southern
California -- RSA is an example of what is known as an asymmetric or
public-key system.
Each merchant on the Web possesses a public RSA key, which is listed
in a public record, and a private key, which is known only to that
merchant. When a message has been locked with a public key, only the
private key can unlock it.
This asymmetry of keys is essential for Internet
transactions because unlike faster "symmetric
key" methods of encryption, RSA does not
require that the sender and the receiver of an
encrypted message meet to transfer a secret
key.
A secure Internet transaction, like a credit card purchase, typically takes
place in a protected tunnel temporarily established between a computer
user's Web browser and an e-commerce site. This protected tunnel,
designed by Netscape but now an Internet standard, is known as SSL,
or Secure Socket Layer.
Since RSA encryption is very slow for long messages, the browser
establishes the tunnel with a faster, symmetric key technique. But then the
symmetric key must be securely transported to the e-commerce site. This
transport depends on RSA.
The transaction uses the strongest encryption that both the Web browser
and the site support. To comply with the export controls, browsers come
in both domestic and exportable versions. The exportable version,
frequently shipped even with computers purchased in the United States,
is limited to 512-bit RSA transactions except with certain authorized sites
-- typically large banks or brokerage firms -- that have paid extra for
stronger encryption capability.
Government controls have been eased since January, enabling a larger
class of sites to use 1,024-bit RSA encryption -- considered secure by
most experts -- in transactions with exportable browsers. But many
restrictions still apply.
The bigger problem, however, is that many Web sites are using 512-bit
encryption for all their Web transactions, regardless of the type of
browser.
While new symmetric keys are generated for each individual transaction,
the RSA key for each individual site typically stays fixed for one year.
This means that a time-consuming code-breaking effort has a huge
payoff: Cracking a single RSA key can potentially unlock a year's worth
of transactions.
"There is no legal reason that American companies should persist in using
low-level encryption for their sites," Thomsen said, adding, "No one in
their right minds should be using 512 today." And yet many major
e-commerce sites, like Microsoft's and Gateway's online stores, are still
using 512-bit encryption for their Web transactions.
While security software can be designed to allow easy upgrades to higher
levels of encryption, the government does not allow manufacturers to
build this capability into their software, said Scott Schnell, senior vice
president for marketing for RSA Data Security and its parent, Security
Dynamics Technologies Inc. Thus, upgrading can be a costly process.
Security Dynamics had $39 million in revenues from encryption software
last year, accounting for 42 percent of the worldwide market, in addition
to licensing the RSA encryption algorithms to more than 500 other
software makers. But Schnell said federal export regulations had hurt
RSA severely in its sales abroad because "no one wants to buy weak
encryption products."
"I think we need a clear base line that makes 1,024 the standard for
public key cryptography," he said.
Even then, the pace at which cryptography standards will be broken may
only increase. "In another 10 years, we can expect to make another jump
of difficulty level," said Lenstra, the Citicorp computer scientist. "It's
always going to be a race."
Copyright 1999 The New York Times Company
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Robert A. Hettinga <mailto: rah@ibuc.com>
The Internet Bearer Underwriting Corporation <http://www.ibuc.com/>
44 Farquhar Street, Boston, MA 02131 USA
"... however it may deserve respect for its usefulness and antiquity,
[predicting the end of the world] has not been found agreeable to
experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'
