May 2002 - cypherpunks-legacy

Relax this Summer... On a new Hammock
by Offers 30 May '02

30 May '02

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by �� 30 May '02

30 May '02

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Re: When encryption is also authentication...
by Jason Holt 30 May '02

30 May '02

Ian Grigg wrote: [...] >> SSL for commerce is readily in place without batting an eyelid these days. > > Costs are still way too high. This won't change until > browsers are shipped that treat self-signed certs as being > valid. Unfortunately, browser manufacturers believe in > cert-ware for a variety of non-security reasons. [...] Self signed certs defeat the purpose of the certificate chain mechanism, which is not just there to make Veri$ign rich. Mallory can self-sign a cert for bob.com, and hack Alice's DNS to point bob.com at her own site. But it's (theoretically, anyway) much more difficult for her to convince Verisign that she owns bob.com. If we trust Verisign to do that, then we know we're really talking to Bob when we visit bob.com. Now, the ability to add other CAs which we trust would be a nice feature, and if there were more trustworthy CAs which were added to the browsers by default, we could get the costs down closer to the actual overhead of verifying that the supplicant (er, applicant) actually owns the domain he's trying to get a cert for. But anyone can certify themselves as owning amazon.com, and it's critical that my browser tell me when some stranger makes such an assertion on their own. -J

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Re: sources on steganography
by cypherpunk_reader 30 May '02

30 May '02

I AM OSAMA Good one !!! lol -----Original Message----- From: owner-cypherpunks(a)ssz.com [mailto:owner-cypherpunks@ssz.com]On Behalf Of Hector Rosario Sent: Thursday, May 30, 2002 8:42 AM To: Morlock Elloi Cc: cypherpunks(a)lne.com Subject: Re: sources on steganography Why would I be interested in "fool[ing] [you]." All I asked was for some help with sources. If you cannot be of help, at least don't be a hindrance. Besides, don't claim to speak for others. If envy is what drives you, then I suggest that you work on that. hr On Wed, 29 May 2002, Morlock Elloi wrote: > > I am writing my dissertation on steganography. Basically I'm writing a > ^^^^ ^ ^ ^ ^ ^ > > You can't fool us. > > > > ===== > end > (of original message) > > Y-a*h*o-o (yes, they scan for this) spam follows: > Yahoo! - Official partner of 2002 FIFA World Cup > http://fifaworldcup.yahoo.com

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Re: Forward-secure public-key encryption eprint
by Anonymous 30 May '02

30 May '02

David Hopwood writes: > Forward-secure public-key encryption has been discussed here, on > sci.crypt, and elsewhere. To recap - the goal is that an adversary who > breaks into your computer today can't read messages sent/received > yesterday. In the interactive case, you use ephermal Diffie-Hellman. The > non-interactive case is more complicated and has had some ideas considered > by Ross Anderson, Adam Back, and David Hopwood (among others). Cypherpunks > relevance: forward security is nice for remailers. > > Anyway, there's a new eprint up which shows how to construct such a scheme > starting from an ID-based encryption scheme by Boneh + Franklin. > > "A Forward-Secure Public-Key Encryption Scheme" > Jonathan Katz > http://eprint.iacr.org/2002/060/ > > It's worth noting that the scheme this is based on has code available. > http://crypto.stanford.edu/ibe/download.html Adam Back noted several years ago that identity-based encryption systems could be converted into forward-secure PK encryption methods. At the time it did not appear that any of the identity-based encryption systems were very secure. In the past few years a number of cryptographic results have been achieved by using the Weil and Tate pairings, which are mappings among groups associated with supersingular elliptic curves. These mappings have special mathematical properties which give a new slant to a number of cryptographic problems. For example it can be shown that in the appropriate group, the Decision Diffie-Hellman problem is easy while the Diffie-Hellman problem is still thought to be hard. On coderpunks this was discussed as a possible approach to ecash. The Weil pairing can also be used to create short signatures, only 20 bytes long for the same security as a DSA sig taking 40 bytes. At Crypto 2001, Boneh and Franklin showed how to use the Weil pairing to create an identity based PK system. Unlike earlier constructions, this one seems to have a good security margin. Following Adam Back's earlier idea, this means a forward-secure PKCS can be constructed, and the new paper does so, using the Weil and Tate pairings. One concern is that these mathematical techniques are new in cryptography and so it is possible that new attacks will be found against them. While the underlying math is old, the specific application is new and so weaknesses may still be discovered. Another problem is that the math is really advanced and not many implementors or users are likely to understand it very well. Sure we've got a library but the kind of people who want forward security would like to understand the principles a little better.

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by RUDOLF 30 May '02

30 May '02

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by ��ȣ�� 30 May '02

30 May '02

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Re: sources on steganography
by Peter Wayner 30 May '02

30 May '02

At 11:19 AM -0400 5/29/02, Hector Rosario wrote: >I am writing my dissertation on steganography. Basically I'm writing a >technical monograph that would be of use to undergraduate instructors. >What do you think are the best sources on steganography on >the Web? What about books other than Johnson, Katzenbeiser & Peticolas, >and the volumes covering the four international workshops on information >hiding. I know that my book, _Disappearing Cryptography_, is being used as a textbook in a few schools. It's a bit broader than the others because it uses a more inclusive view of the topic. You can read a bit more here: http://www.wayner.org/books/discrypt2/ The book on Watermarking by Cox et al is also very nice, although very focused and very detailed. -Peter

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Re: sources on steganography
by Graham Lally 30 May '02

30 May '02

Hector Rosario wrote: > Why would I be interested in "fool[ing] [you]." All I asked was for some > help with sources. If you cannot be of help, at least don't be a > hindrance. Besides, don't claim to speak for others. If envy is what > drives you, then I suggest that you work on that. > > hr > > On Wed, 29 May 2002, Morlock Elloi wrote: > > >>>I am writing my dissertation on steganography. Basically I'm writing a > ^^^^ ^ ^ ^ ^ ^ >> >>You can't fool us. ...or "I am storb." for the proportionally-gifted.

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Re: sources on steganography
by Steve Furlong 30 May '02

30 May '02

Hector Rosario wrote: > > Why would I be interested in "fool[ing] [you]." All I asked was for some ^ ^ ^ ^ > help with sources. If you cannot be of help, at least don't be a ^ ^ ^ > hindrance. Besides, don't claim to speak for others. If envy is what ^ ^ ^ > drives you, then I suggest that you work on that. ^ ^ ^ ^ -- Steve Furlong Computer Condottiere Have GNU, Will Travel Vote Idiotarian --- it's easier than thinking

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