rfid problems again

[Nexus <dave () farber net>]

------- Original message -------
From: Stephen D. Poe <sdpoe () acm org>
Sent: 24/3/'05,  10:56

Dave -

For IP, if you like.

Stephen
---
RSA Finds More Flaws in RFID
March 23, 2005
By Jacqueline Emigh

After uncovering a security weakness in a radio-frequency identification
tag from Texas Instruments Inc., researchers from RSA Security Inc.'s
RSA Laboratories and The Johns Hopkins University are now eyeing future
exploits against other RFID products in the interests of better
security, one of the researchers said this week.

Meanwhile, TI will keep making the compromised RFID tag in order to meet
the needs of applications more sensitive to speed and pricing than to
privacy, according to a TI official.

The Johns Hopkins University Information Security Institute and RSA
first publicized their findings about the RFID security hole in January.

In a paper posted at www.rfidanalysis.org, the researchers claim that by
cracking a proprietary cipher, or encryption algorithm in one of TI's
DST (digital signature transponder) RFID tags, they were able to
circumvent the tags' built-in security enough to buy gasoline and turn
on a car's ignition.

Paul Sabetti, global business manager for TI's RFID Systems,
acknowledged that the DSTs contain some proven vulnerabilities. But
Sabetti also described the security risk as relatively minimal, calling
it a "tradeoff" that some makers of electronic payment and vehicle
immobilization systems are willing to accept. Some of TI's customers in
these niches produce car keys or tokens, and others, complete systems.

The RFID tags compromised by Johns Hopkins and RSA-part of TI's DST-40
tag lineup-use a proprietary 40-bit encryption algorithm first written
in 1999.

"Why are we using a proprietary algorithm? Because it's faster [that
way] to produce inexpensive chips," Sabetti said.

The researchers from Johns Hopkins and RSA reverse-engineered and
emulated the 40-bit encryption over two months.

But DST-40 tags are only one part of a larger RFID portfolio that also
includes a DST "Plus" edition-featuring "a series of memory features and
encryption scalable to 80 bits"-as well as an "RFID credit card" lineup
with industry-standard 128-bit Triple DES encryption, he said.

eWEEK Labs Director Jim Rapoza says security is being trampled in the
rush to put RFID everywhere. Click here to read his column.

TI keeps "vigilantly improving" products across this portfolio,
according to Sabetti. But, he said, TI has no immediate plans to stop
using the proprietary 40-bit cipher in its DST-40 tags. Customers that
choose DST-40 tags from TI's lineup are generally seeking a combination
of low pricing and quick processing speeds.

In a vehicle immobilization application, for example, it takes the
40-bit encryption scheme only about 250 milliseconds to "wake up the
tag, do the encryption and encoding, and confirm that everything's
correct," Sabetti said.

"But if you put [128-bit] Triple DES in there, all this would take 2 to
3 seconds-and that wouldn't be acceptable to most consumers."

Few people would be able to replicate the attack, anyway, Sabetti said.
"Deciphering a 40-bit key isn't really that special of an event. But
this was the work of professional mathematicians, statisticians, and
cryptographers."

Moreover, TI's customers add other levels of security at the application
layer, according to Sabetti.

Next page: Striking a balance between speed, cost and security.

One of TI's customers, Exxon Mobil Corp., uses the DST-40 tag in its
Speedpass electronic payment system.

"We've been over all of this with Exxon, and they don't see any more
risk [now] beyond the risk they were at already," Sabetti said.

Ari Juels, RSA's principal research scientist, agreed that customers
have a right to try to "strike a balance" between speed, cost, and security.

"But what we're saying is that if you're going to bother to build in
encryption at all, you should do it correctly. You shouldn't use a
proprietary encryption algorithm," Juels said.

Other companies also make RFID tags for the same general markets. Why
did the researchers focus only on TI? "Because TI is the most visible."
Juels said.

But TI wasn't being "picked on," he said. "We're also intending to look
at a range of [other] RFID systems, [including both] active and passive
RFID tags. Various [RFID systems] have various security and privacy
weaknesses."

Click here to read about RSA's RFID security services.

For his part, Sabetti took issue with some of the cryptographic
researchers' methods and findings.

The DST simulation system used in the attacks "took up the entire back
seat of a car," he said. "[The researchers] were unable to produce an
emulator which would be considered small or efficient."

Sabetti also said that the RSA and Johns Hopkins researchers had
demonstrated the attack for him, and that during the demo, they hadn't
been able to intercept information outside of a two-foot range.

"[Two feet] is a bit naïve," Juels said. "That is the nominal read
range. Other systems, [with] a gate antenna, might achieve several feet
for active scanning. Also, if an attacker waits until someone is
[actually] using a Speedpass token, the potential passive eavesdropping
range could be 10 feet."

But Juels admitted that the researchers used only "crude" equipment in
the attack against TI's 40-bit encryption.

"Our attempt to do this was rather crude and uninformed, [and] cobbled
together with some fairly inexpensive equipment. [But] once these
systems have been widely deployed, there will be better equipment
available. This was only a proof-of-concept [attack]," he said.
- http://www.eweek.com/print_article2/0,2533,a=148333,00.asp




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