Full Disclosure mailing list archives

RE: On PGP (was: Wiretap or Magic Lantern?)


From: Tremaine Lea <tremaine.lea () sjrb ca>
Date: Wed, 07 Apr 2004 12:57:10 -0600

To assume a gov't agency with the resources of the NSA is unable to read
PGP/GPG encrypted mail is sheer folly.  All discussion to date is based
around the assumption that you are attempting to brute force an individual
message in the classical sense of brute force.

1: encrypted message
2: attempt brute force until it breaks or you get tired of waiting and give
up.


The above and classic use of brute force ignores a critical factor.  The NSA
and others have the resources to have cycles spent doing nothing but brute
force style attacks, and the storage to *store the results*

The failure thus far has been in throwing out results that didn't match the
specific message one was attempting to crack.  If on the other hand the
systems are used to brute force and store it's resulting attempts, the
results that failed for one message may be successful for another, and
obviate the need to actively crack that specific message at the time it's
presented.

Tremaine

-----Original Message-----
From: Feher Tamas [mailto:etomcat () freemail hu] 
Sent: Wednesday, April 07, 2004 9:57 AM
To: full-disclosure () lists netsys com
Subject: [Full-disclosure] On PGP (was: Wiretap or Magic Lantern?)

Hello,

The terrorsts are not stupid, they use strong encryption 
and there is 
proof that PGP repels NSA.

What proof are you referring to? 

The case of the italian comrades:

http://www.pcworld.com/news/article/0,aid,110841,00.asp

PGP Encryption Proves Powerful
by Philip Willan, IDG News Service, 26 May 2003

If the police and FBI can't crack the code, is the technology 
too strong?

Italian police have seized at least two Psion personal 
digital assistants from members of the Red Brigades terrorist 
organization. But the major investigative breakthrough they 
were hoping for as a result of the information contained on 
the devices has failed to materialize-- thwarted by 
encryption software used by the left-wing revolutionaries.

Failure to crack the code, despite the reported assistance of U.S. 
Federal Bureau of Investigation computer experts, puts a 
spotlight on the controversy over the wide availability of 
powerful encryption tools.

The Psion devices were seized on March 2 after a shootout on 
a train traveling between Rome and Florence, Italian media 
and sources close to the investigation said. The devices, 
believed to number two or three, were seized from Nadia 
Desdemona Lioce and her Red Brigades comrade Mario Galesi, 
who was killed in the shootout. An Italian police officer was 
also killed. At least one of the devices contains information 
protected by encryption software and has been sent for 
analysis to the FBI facility in Quantico, Virginia, news 
reports and sources said.

The FBI declined to comment on ongoing investigations, and 
Italian authorities would not reveal details about the 
information or equipment seized during the shootout.

Pretty Good Privacy
The software separating the investigators from a potentially 
invaluable mine of information about the shadowy terrorist 
group, which destabilized Italy during the 1970s and 1980s 
and revived its practice of political assassination four 
years ago after a decade of quiescence, was PGP (Pretty Good 
Privacy), the Rome daily La Repubblica reported. 
So far the system has defied all efforts to penetrate it, the 
paper said.

Palm-top devices can only run PGP if they use the Palm OS or 
Windows CE operating systems, said Phil Zimmermann, who 
developed the encryption software in the early 1990s. Psion 
uses its own operating system known as Epoc, but it might 
still be possible to use PGP as a third party add-on, a 
spokesperson for the British company said.

There is no way that the investigators will succeed in 
breaking the code with the collaboration of the current 
manufacturers of PGP, the Palo Alto, California-based PGP, 
Zimmermann said in a telephone interview.

"Does PGP have a back door? The answer is no, it does not," 
he said. "If the device is running PGP it will not be 
possible to break it with cryptanalysis alone."

Investigators would need to employ alternative techniques, 
such as looking at the unused area of memory to see if it 
contained remnants of plain text that existed before 
encryption, Zimmermann said.

Privacy vs. Security
The investigators' failure to penetrate the PDA's encryption 
provides a good example of what is at stake in the 
privacy-versus-security debate, which has been given a whole 
new dimension by the September 11 terrorist attacks in the U.S.

Zimmermann remains convinced that the advantages of PGP, 
which was originally developed as a human rights project to 
protect individuals against oppressive governments, outweigh 
the disadvantages.

"I'm sorry that cryptology is such a problematic technology, 
but there is nothing we can do that will give this technology 
to everyone without also giving it to the criminals," he 
said. "PGP is used by every human rights organization in the 
world. It's something that's used for good. It saves lives."

Nazi Germany and Stalin's Soviet Union are examples of 
governments that had killed far more people than all the 
world's criminals and terrorists combined, Zimmermann said. 
It was probably technically impossible, Zimmermann said, to 
develop a system with a back door without running the risk 
that the key could fall into the hands of a Saddam Hussein or 
a Slobodan Milosevic, the former heads of Iraq and 
Yugoslavia, respectively.

"A lot of cryptographers wracked their brains in the 1990s 
trying to devise strategies that would make everyone happy 
and we just couldn't come up with a scheme for doing it," he said.

"I recognize we are having more problems with terrorists now 
than we did a decade ago. Nonetheless the march of 
surveillance technology is giving ever increasing power to 
governments. We need to have some ability for people to try 
to hide their private lives and get out of the way of the 
video cameras," he said.

More Good Than Harm?
Even in the wake of September 11, Zimmermann retains the view 
that strong cryptography does more good for a democracy than 
harm. His personal website, PhilZimmerman.com, contains 
letters of appreciation from human rights organizations that 
have been able to defy intrusion by oppressive governments in 
Guatemala and Eastern Europe thanks to PGP. One letter 
describes how the software helped to protect an Albanian 
Muslim woman who faced an attack by Islamic extremists 
because she had converted to Christianity.

Zimmermann said he had received a letter from a Kosovar man 
living in Scandinavia describing how the software had helped 
the Kosovo Liberation Army (KLA) in its struggle against the 
Serbs. On one occasion, he said, PGP-encrypted communications 
had helped to coordinate the evacuation of 8,000 civilians 
trapped by the Serbs in a Kosovo valley. "That could have 
turned into another mass grave," 
Zimmermann said.

Italian investigators have been particularly frustrated by 
their failure to break into the captured Psions because so 
little is known about the new generation of Red Brigades. 
Their predecessors left a swathe of blood behind them, 
assassinating politicians, businessmen, and security 
officials and terrorizing the population by "knee-capping," 
or shooting in the legs, perceived opponents. Since 
re-emerging from the shadows in 1999 they have shot dead two 
university professors who advised the government on labor law reform.

Cracking the Code
Zimmermann is not optimistic about the investigators' chances 
of success. "The very best encryption available today is out 
of reach of the very best cryptanalytic methods that are 
known in the academic world, and it's likely to continue that 
way," he said.

Sources close to the investigation have suggested that they 
may even have to turn to talented hackers for help in 
breaking into the seized devices. One of the magistrates 
coordinating the inquiry laughed at mention of the idea. "I 
can't say anything about that," he said.

The technical difficulty in breaking PGP was described by an 
expert witness at a trial in the U.S. District Court in 
Tacoma, Washington, in April 1999. Steven Russelle, a 
detective with the Portland Police Bureau, was asked to 
explain what he meant when he said it was not 
"computationally feasible" to crack the code. "It means that 
in terms of today's technology and the speed of today's 
computers, you can't put enough computers together to crack a 
message of the kind that we've discussed in any sort of 
reasonable length of time," he told the court.

Russelle was asked whether he was talking about a couple of 
years or longer. "We're talking about millions of years," he replied.

[BTW: I read the ring was dismantled later, because one of 
the GSM mobile phones they used had to be repaired months 
earlier and the shop owner has preserved the telephone number 
they gave for notification when the unit is ready. His repair 
warrantly sticker was found inside the confiscated phone and 
so the law enforcement contacted him. Parsing the telco's 
history log for calls to / from that single number revealed 
almost the entire cell's structure. So make yourself a favour 
and buy a disposable mobile phone next time! Unless you are 
an environmental terrorist of course...]

Sincerely: Tamas Feher.

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