Re: AES Modes

2004-10-13 Thread Brian Gladman
Ian Grigg wrote:
Jack Lloyd also passed along lots of good comments I'd
like to forward (having gained permission) FTR.  I've
edited them for brevity and pertinence.
[snip]
 I'm obviously being naive here ... I had thought that the combined 
mode would
  be faster, as it would run through the data once only, and that AES 
seems to
  clip along faster than SHA1.

AFAIK all of the modes that use only one block cipher invocation per 
block of
input are patented. EAX+CCM both use two AES operations per block, and
byte-for-byte SHA-1 is 2-5x faster than AES (at least in the 
implementations
I've seen/used/written), so using AES+HMAC is probably going to be 
faster than
AES/EAX or AES/CCM. The obvious exception being boxes with hardware AES 
chips
and slow CPUs (eg, an ARM7 with an AES coprocessor), where AES will of 
course
be much faster than SHA-1.
Maybe my C implementation of SHA1 is hopeless but I get SHA1 on an x86 
at about 17 cycles per byte (over 100,000 bytes) and AES in C at 21 
cycles per byte.

So I would put these two algorihms at about the same speed in C. In 
consequence I rather suspect that the 'two encryptions per block' cost 
might also apply to combined modes when AES is used with HMAC-SHA1.

Rich Schroeppel's CS mode has been added to the NIST modes list earlier 
this year and is not patented. It seems to have a cost that is close to 
'one encryption per block' but it has the 'interesting' property of 
using the internal 'mid-point' state of the cipher algorithm that is in use.

   Brian Gladman
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Airline ID requirement faces legal challenge

2004-10-13 Thread R.A. Hettinga
http://www.usatoday.com/tech/news/surveillance/2004-10-10-privacy_x.htm

USA Today



Airline ID requirement faces legal challenge
By Richard Willing, USA TODAY
At a time when Americans have come to expect tight security for air travel,
it might seem to be an odd question: Does requiring airline passengers to
show identification before they board domestic flights amount to an
unreasonable search under the Constitution?

John Gilmore is challenging the federal domestic airline ID requirement,
saying it violates his right to travel in the USA anonymously.
File photo

Yes, says John Gilmore, a computer whiz who made a fortune as an early
employee of Sun Microsystems. His challenge of the federal ID requirement,
which soon could get a hearing before a U.S. appeals court in San
Francisco, is one of the latest court battles to test the balance between
security concerns and civil liberties.

 At issue is Gilmore's claim that checking the IDs of passengers on
domestic flights violates his right to travel throughout the USA
anonymously, without the government monitoring him.

 Lawyers involved in the case say it apparently is the first such challenge
to the federal rules that require airline passengers to provide
identification. In a similar case, two peace activists are suing the U.S.
government to determine how their names came to be placed on a federal
no-fly list. Rebecca Gordon and Janet Adams were not allowed to board a
San Francisco to Boston flight in August 2002 after they were told that
their names were on a secret FBI list of potential security threats,
their court filing says.

I believe I have a right to travel in my own country without presenting
what amounts to an internal passport, Gilmore, 49, said in an interview.
I have a right to be anonymous, (to not) be tracked by my government for
no good reason.

Gilmore said he has no problem with security checks that focus on
passengers' luggage. He says he also does not object to having to present a
passport to board flights to other countries.

 Some privacy groups say Gilmore has a point. But others who support the ID
requirement have cast the San Francisco resident as being out of touch with
the realities of air travel since the Sept. 11 attacks.

Kent Scheidegger, counsel for the Criminal Justice Legal Foundation, a
conservative group in Sacramento, says the ID requirement is good policy
and eminently constitutional.

The Fourth Amendment forbids not searches that you don't like, it forbids
unreasonable searches, he says. Nothing could be more reasonable at this
time than to know who you're flying with.

 The Justice Department is fighting Gilmore's claim. Acting on the
department's motion, a U.S. district court judge in San Francisco dismissed
the suit last March. Gilmore has appealed; a hearing before the 9th Circuit
Court of Appeals is likely to be scheduled after briefs are filed next
month.

In court papers, the Justice Department has not defended the ID policy, or
even acknowledged it exists. It has said national security law requires
that this aspect of the case be argued in a courtroom closed to the public,
including Gilmore. The appeals court denied the government's secrecy
request Sept. 20, and the government has asked the court to reconsider.

 Rules on the Transportation Security Administration's Web site say
passengers 18 and older need one form of government-issued photo
identification or two forms of non-photo identification to board domestic
flights.

 Airlines adopted such a policy on their own after terrorists bombed an
international flight over Lockerbie, Scotland, in December 1988. The bomb
that killed all 270 passengers on the jet was said to have been placed in a
passenger's luggage by a terrorist who got into a restricted area. The
airlines say checking IDs against luggage and passenger information is a
way to deny terrorists access to flights.

The TSA, formed two years ago in the wake of the Sept. 11 attacks, checks
IDs to verify passenger identities and to check them against watch lists
of known or suspected terrorists.

Gilmore's suit says the requirement amounts to an unreasonable search, a
burden on the right to travel and a form of self-incrimination because it
singles out anonymous travelers for searching.

Gilmore said the ID requirement does little to ensure security. Ordinary
citizens may show correct identification, but do we really think that
someone who is willing to commit a terrorist act won't also be willing to
present false identification?

Gilmore's suit was filed in 2002, after he was denied seats on two flights
at the airport in Oakland. It was his first domestic flight since the 9/11
attacks. Before then, Gilmore said, he was permitted to board flights after
presenting a Federal Aviation Administration document that said showing IDs
was optional.

In 1982, Gilmore, a computer programmer, was the first person hired by the
founders of what became Sun Microsystems. He retired eight years ago with
what his