Re: Decimal encryption
Wed, 27 Aug 2008 21:27:00 +0000
"Hal Finney" wrote:>> So, you don't have a 133-bit block cipher lying around? No worries, I'll>> sell you one ;-). Actually that is easy too. Take a trustworthy 128-bit>> block cipher like AES. To encrypt, do:>>>> 1. Encrypt the first 128 bits (ECB mode)>> 2. Encrypt the last 128 bits (also ECB mode).>> I didn't understand this at first, but I finally saw that the point is to> do the encryptions .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 20:50:00 +0000
Looking a little more closely, I found this paper by Patarin fromCrypto 2005 which describes security bounds for higher round Feistelconstructions:http://www.springerlink.com/content/gtcabev3ucv8apdu/As we know, the Luby-Rackoff 4 round construction gives you basically2^(n/2) security in the number of messages, where n is half thewidth of the output (i.e. n is the size of each half in the .. .. read more..
Re: road toll transponder hacked
Wed, 27 Aug 2008 20:36:00 +0000
> Personally, I don't want to have a history of my travel stored in any > database. Right now, purchasing a one-time CharlieTicket is a 30 cent > surcharge per ride, but it is the only way to take the subway in Boston > without creating a travel history. Privacy in public transportation > should be equally accessible to all citizens, regardless of financial > resources.I suspect that you, as do I .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 20:34:00 +0000
At Wed, 27 Aug 2008 16:10:51 -0400 (EDT),Jonathan Katz wrote:>> On Wed, 27 Aug 2008, Eric Rescorla wrote:>>> At Wed, 27 Aug 2008 17:05:44 +0200,>> There are a set of techniques that allow you to encrypt elements of>> arbitrary sets back onto that set.>>>> The original paper on this is:>> John Black and Phillip Rogaway. Ciphers with arbitrary ?nite domains. In>> CT-RSA, pages 114?130, .. .. read more..
Re: SRP implementation - choices for N and g
Wed, 27 Aug 2008 20:21:00 +0000
Michael Tschannen wrote:> Hi list>> Has anybody already gained experience concerning the technical> implementation of SRP (http://srp.stanford.edu)? There is one point I> couldn't find in any documentation: Should the modulus and the generator> (N and g) be unique for each client or can they be chosen> application-wide? What are the (security-related) implications in each> case?There is no .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 20:19:00 +0000
On Wed, 27 Aug 2008 09:34:15 -0700Greg Rose wrote: > So, you don't have a 133-bit block cipher lying around? No worries,> I'll sell you one ;-). Also see Debra Cook's PhD dissertation on Elastic Block Ciphers athttp://www1.cs.columbia.edu/~dcook/thesis_ab.shtml --Steve Bellovin, http://www.cs.columbia.edu/~smb-------------------------------------------------------------------- .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 20:19:00 +0000
Philipp Gühring wote:> I am searching for symmetric encryption algorithms for decimal strings.>> Let's say we have various 40-digit decimal numbers:> 2349823966232362361233845734628834823823> 3250920019325023523623692235235728239462> 0198230198519248209721383748374928601923>> As far as I calculated, a decimal has the equivalent of about 3,3219> bits, so with 40 digits, we have about 132,877 .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 20:10:00 +0000
On Wed, 27 Aug 2008, Eric Rescorla wrote:> At Wed, 27 Aug 2008 17:05:44 +0200,> Philipp Gühring wrote:>>>> Hi,>>>> I am searching for symmetric encryption algorithms for decimal strings.>>>> Let's say we have various 40-digit decimal numbers:>> 2349823966232362361233845734628834823823>> 3250920019325023523623692235235728239462>> 0198230198519248209721383748374928601923>>>> As far as I calculated, .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 19:36:00 +0000
I like Greg Rose's solution best:> There is a fairly standard technique for handling things like this.>> 1. encode your number N into a 133-bit string S> 2. encrypt S with your favourite 133-bit block cipher (see below)> 3. decode S to a number N'> 4. if N' >= 10^40, goto 2 (that is, re-encrypt until it is in range)> 5. N' is your answer.This is Rich Schroeppel's trick from his Hasty Pudding .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 18:45:00 +0000
On Wed, Aug 27, 2008 at 11:05 AM, Philipp Gühring wrote:> I am searching for symmetric encryption algorithms for decimal strings.> Since the 132,877 bits is similar to 128 bit encryption (like eg. AES),> I would like to use an algorithm with a somewhat comparable strength to AES.> But the problem is that I have 132,877 bits, not 128 bits. And I can't> cut it off or enhance it, .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 18:32:00 +0000
Philipp Gühring writes:> I am searching for symmetric encryption algorithms for decimal strings.>> Let's say we have various 40-digit decimal numbers:> 2349823966232362361233845734628834823823> 3250920019325023523623692235235728239462> 0198230198519248209721383748374928601923>> As far as I calculated, a decimal has the equivalent of about 3,3219> bits, so with 40 digits, we have about 132,877 .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 16:34:00 +0000
Philipp Gühring wrote:> Hi,G'day Philipp,> I am searching for symmetric encryption algorithms for decimal strings.>> Let's say we have various 40-digit decimal numbers:> 2349823966232362361233845734628834823823> 3250920019325023523623692235235728239462> 0198230198519248209721383748374928601923>> As far as I calculated, a decimal has the equivalent of about 3,3219> bits, so with 40 digits, we .. .. read more..
Re: road toll transponder hacked
Wed, 27 Aug 2008 16:16:00 +0000
On Wed, 27 Aug 2008 07:10:51 -0400dan@geer.org wrote:>> Bill Frantz writes, in part:> -+--------------------------> | In the San Francisco Bay Area, they are using the transponder codes> | to measure how fast traffic is moving from place to place. They> | post the times to various destinations on the electric signs when> | there are no Amber alerts or other more important things to> | .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 16:12:00 +0000
On Wed, 27 Aug 2008 17:05:44 +0200Philipp G__hring wrote:> Hi,>> I am searching for symmetric encryption algorithms for decimal> strings.>> Let's say we have various 40-digit decimal numbers:> 2349823966232362361233845734628834823823> 3250920019325023523623692235235728239462> 0198230198519248209721383748374928601923>> As far as I calculated, a decimal has the equivalent of .. .. read more..
Re: road toll transponder hacked
Wed, 27 Aug 2008 16:06:00 +0000
dan@geer.org wrote:> Look for general tracking to appear everywhere.Anonymous travel is dead. Even for subway riders who still use tokensand citizens that bicycle around town, the proliferation of cameras,facial recognition technology, biometrics and RFID tagging will renderanonymity obsolete within a generation.I believe the public's next battleground is to gain control over what*happens* to our .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 15:42:00 +0000
Philipp Gühring wrote:> Hi,>> I am searching for symmetric encryption algorithms for decimal strings.>> Let's say we have various 40-digit decimal numbers:> 2349823966232362361233845734628834823823> 3250920019325023523623692235235728239462> 0198230198519248209721383748374928601923>> As far as I calculated, a decimal has the equivalent of about 3,3219> bits, so with 40 digits, we have about .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 15:35:00 +0000
=?ISO-8859-15?Q?Philipp_G=FChring?= writes:>Does anyone know a an algorithm that has reasonable strength and is able to>operate on non-binary data? Preferrably on any chosen number-base?I posted a description of how to perform encryption in limited subranges tosci.crypt about ten years ago,http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=5c8sin%24piv% .. .. read more..
Re: road toll transponder hacked
Wed, 27 Aug 2008 15:29:00 +0000
On Aug 27, 2008, at 7:10 AM, dan@geer.org wrote:> The relationship to this list may then be thin> excepting that the collection and handling of> such data remains of substantial interest.Actually, it points to cash settlement of road tolls.Most likely digital bearer transaction settlement, in the long run.But y'all knew I'd say that, right?:-)Cheers,RAH-------------------------------------------- .. .. read more..
Re: Decimal encryption
Wed, 27 Aug 2008 15:19:00 +0000
At Wed, 27 Aug 2008 17:05:44 +0200,Philipp Gühring wrote:>> Hi,>> I am searching for symmetric encryption algorithms for decimal strings.>> Let's say we have various 40-digit decimal numbers:> 2349823966232362361233845734628834823823> 3250920019325023523623692235235728239462> 0198230198519248209721383748374928601923>> As far as I calculated, a decimal has the equivalent of about 3,3219> bits, .. .. read more..
Decimal encryption
Wed, 27 Aug 2008 15:05:00 +0000
Hi,I am searching for symmetric encryption algorithms for decimal strings.Let's say we have various 40-digit decimal numbers:234982396623236236123384573462883482382332509200193250235236236922352357282394620198230198519248209721383748374928601923As far as I calculated, a decimal has the equivalent of about 3,3219bits, so with 40 digits, we have about 132,877 bits.Now I would like to encrypt those .. .. read more..
Re: road toll transponder hacked
Wed, 27 Aug 2008 11:10:00 +0000
Bill Frantz writes, in part:-+-------------------------- | In the San Francisco Bay Area, they are using the transponder codes | to measure how fast traffic is moving from place to place. They | post the times to various destinations on the electric signs when | there are no Amber alerts or other more important things to | display. It is quite convenient, and they promise they don't use it | to .. .. read more..
Re: SRP implementation - choices for N and g
Wed, 27 Aug 2008 04:43:00 +0000
[Moderator's reminders: 1) 80 column text is easier for many of us to read. 2) Top posting considered harmful. 3) Trim quoted text, and please use ">" quoting if possible. --Perry]Michael,I'd recommend taking a look a RFC 5054 (http://www.ietf.org/rfc/rfc5054.txt). Nearly all applications of SRP use application-wide choices for N and g, usually the ones standardized by IETF. .. .. read more..
OpenSSH compromise at Red Hat
Wed, 27 Aug 2008 00:09:00 +0000
I'm a bit surprised no one has mentioned the Red Hat server being hacked and the certificated being compromised on Fedora.http://www.eweek.com/c/a/Security/Red-Hat-Digital-Keys-Violated-By-Intruder/Best,Allen---------------------------------------------------------------------The Cryptography Mailing ListUnsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com .. .. read more..
Re: road toll transponder hacked
Tue, 26 Aug 2008 21:40:00 +0000
ken.buchanan@gmail.com (Ken Buchanan) on Tuesday, August 26, 2008 wrote:>I think this is a bit different than what Michael Heyman said. TxTag,>IIRC, was implemented by the same company (Raytheon) that implemented>the 407 ETR toll system in Toronto. In the case of the 407, there is>no image recognition done if the car has a valid transponder. Only in>the case of a missing or invalid transponder .. .. read more..
Re: road toll transponder hacked
Tue, 26 Aug 2008 18:24:00 +0000
On Tue, 2008-08-26 at 13:22 -0400, Ken Buchanan wrote:> On Tue, Aug 26, 2008 at 11:56 AM, Dustin D. Trammell> wrote:>> This is the same for the state-wide Texas tag, TxTag[1]. If your tag>> doesn't register, or you disable or remove it, the toll system can still>> accurately bill you based on your license plate and vehicle>> registration. If you're not in the TxTag .. .. read more..