Re: Secure erasing Info (fwd from richard@SCL.UTAH.EDU)

2005-05-02 Thread Jason Holt
On Mon, 2 May 2005, sunder wrote: Yeah, but these days, I'd go with the largest flash drive I could afford. USB2 or otherwise. I don't believe you can recover data from these once you actually overwrite the bits (anyone out there know any different?). There are lots of pitfalls in

RE: Dell to Add Security Chip to PCs

2005-02-04 Thread Jason Holt
On Thu, 3 Feb 2005, Erwann ABALEA wrote: And do you seriously think that you can't do that, it's technically not possible is a good answer? That's what you're saying. For me, a better answer is you don't have the right to deny my ownership. Yes, Senator McCarthy, I do in fact feel safer

Hiawatha's research

2004-06-16 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hiawatha's Research Jason Holt [EMAIL PROTECTED] June, 2004, released into the public domain. Dedicated to Eric Rescorla, with apologies to Longfellow. (E. Rescorla may be substituted for Hiawatha throughout.) Hiawatha, academic, he could start ten

Re: who goes 1st problem

2004-05-11 Thread Jason Holt
[Adam and I are taking this discussion off-list to spare your inboxes, but this message seemed particularly relevant. Perhaps we'll come back later if we come up with anything we think will be of general interest.] -J On Tue, 11 May 2004, Adam Back

Re: who goes 1st problem

2004-05-11 Thread Jason Holt
[Adam and I are taking this discussion off-list to spare your inboxes, but this message seemed particularly relevant. Perhaps we'll come back later if we come up with anything we think will be of general interest.] -J On Tue, 11 May 2004, Adam Back

Re: blinding BF IBE CA assisted credential system (Re: chaum's patent expiry?)

2004-05-10 Thread Jason Holt
On Mon, 10 May 2004, Adam Back wrote: On Mon, May 10, 2004 at 03:03:56AM +, Jason Holt wrote: [...] Actually, now that you mention Chaum, I'll have to look into blind signatures with the BF IBE (issuing is just a scalar*point multiply on a curve). I think you mean so that the CA

Re: Brands' private credentials

2004-05-10 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Mon, 10 May 2004, Adam Back wrote: After that I was presuming you use a signature to convince the server that you are authorised. Your comment however was that this would necessarily leak to the server whether you were a doctor or an AIDs

Re: more hiddencredentials comments (Re: Brands' private credentials)

2004-05-10 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Mon, 10 May 2004, Adam Back wrote: OK that sounds like it should work. Another approach that occurs is you could just take the plaintext, and encrypt it for the other attributes (which you don't have)? It's usually not too challenging to

Re: Brands' private credentials

2004-05-10 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Mon, 10 May 2004, Adam Back wrote: After that I was presuming you use a signature to convince the server that you are authorised. Your comment however was that this would necessarily leak to the server whether you were a doctor or an AIDs

Re: more hiddencredentials comments (Re: Brands' private credentials)

2004-05-10 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Mon, 10 May 2004, Adam Back wrote: OK that sounds like it should work. Another approach that occurs is you could just take the plaintext, and encrypt it for the other attributes (which you don't have)? It's usually not too challenging to

Re: Brands' private credentials

2004-05-09 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Sun, 9 May 2004, Adam Back wrote: and seeing that it is a completely different proposal essentially being an application of IBE, and extension of the idea that one has multiple identities encoding attributes. (The usual attribute this

Re: Brands' private credentials

2004-05-09 Thread Jason Holt
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On Sun, 9 May 2004, Adam Back wrote: and seeing that it is a completely different proposal essentially being an application of IBE, and extension of the idea that one has multiple identities encoding attributes. (The usual attribute this

Re: Trivial OTP generation method? (makernd.c)

2003-02-27 Thread Jason Holt
Several things: * Using the output to seed MD5 for the next block exposes that part of the state of the RNG. Might be better to use half the MD5 output as seed for the next block, and the other half as output data. * Your RNG takes input from an attackable source. I can significantly reduce

Re: patent free(?) anonymous credential system pre-print - a simpleattack and other problems

2002-11-06 Thread Jason Holt
(Re: my paper at http://eprint.iacr.org/2002/151/ ) Stefan Brands wrote: - The system is subject to a simple attack. The problem lies with the multiplication of the hashes. Let's take the Chaum blinding as an [...] (For our readers at home, that was the vulnerability I mentioned in

Re: patent free(?) anonymous credential system pre-print - a simpleattack and other problems

2002-11-05 Thread Jason Holt
(Re: my paper at http://eprint.iacr.org/2002/151/ ) Stefan Brands wrote: - The system is subject to a simple attack. The problem lies with the multiplication of the hashes. Let's take the Chaum blinding as an [...] (For our readers at home, that was the vulnerability I mentioned in

Re: patent free(?) anonymous credential system pre-print

2002-11-05 Thread Jason Holt
(Re: my paper at http://eprint.iacr.org/2002/151/ ) Let me first point out that Dr. Stefan Brands noted an insecurity in my system which would allow malicious users to obtain issuer signatures on arbitrary documents. This is due to the fact that users aren't prevented from using

patent free(?) anonymous credential system pre-print

2002-10-29 Thread Jason Holt
I've submitted a pre-print of my anonymous credential system to the IACR ePrint server. Thanks to all of you who responded to the questions I posted here while working on it. I'd love to hear feedback from any and all before I sumbit it for publication; particularly, I want to make sure I

patent free(?) anonymous credential system pre-print

2002-10-29 Thread Jason Holt
I've submitted a pre-print of my anonymous credential system to the IACR ePrint server. Thanks to all of you who responded to the questions I posted here while working on it. I'd love to hear feedback from any and all before I sumbit it for publication; particularly, I want to make sure I

Re: Chaum's unpatented ecash scheme

2002-08-26 Thread Jason Holt
[...] Speaking of anonymous, you should give credit in your paper to Anonymous for discovering the possibility of marking Lucre coins, in a coderpunks posting at http://www.mail-archive.com/coderpunks@toad.com/msg02186.html, and for inventing the Type II Defence, both in the posting above

Data Security class programming project

2002-08-20 Thread Jason Holt
I'm working on designing the programming projects for a data security class. What do you think of this one? I love its intrinsic irony, but can we actually get away with requiring it for a university class? I mean, Elcomsoft really is in court for this. My University is unfortunately not

Data Security class programming project

2002-08-19 Thread Jason Holt
I'm working on designing the programming projects for a data security class. What do you think of this one? I love its intrinsic irony, but can we actually get away with requiring it for a university class? I mean, Elcomsoft really is in court for this. My University is unfortunately not

Tunneling through hostile proxy

2002-07-23 Thread Jason Holt
Roy M. Silvernail[SMTP:[EMAIL PROTECTED]] Given internet access from a private intranet, through an HTTP proxy out of the user's control, is it possible to establish a secure tunnel to an outside server? I'd expect that ordinary SSL connections will secure user - proxy and proxy - server

Re: Tunneling through hostile proxy

2002-07-23 Thread Jason Holt
On Tue, 23 Jul 2002, Adam Back wrote: [...] However, it is possible for the proxy to have its own CA which has been added to your browser. Then it acts as a man in the middle and pretends to be the remote host to you, and vice versa. In that case, it works as you describe, watching the

Safe RSA variant?

2002-06-14 Thread Jason Holt
Well, I got such a good response from my last technical question that I'll try again :) If it's actually secure, it'll go really well with my credential system. Trent generates primes p,q. He publishes n=pq and some random value g. Trent calculates a and a' such that aa' = 1 % (p-1)(q-1) and

Ben's blinding, plus pre-publishing

2002-06-10 Thread Jason Holt
Maybe you could say more about the details of your credential system. Such a system built on Wagner blinding might be very interesting. I've been thinking it would be nice to post my entire paper here (and maybe on sci.crypt.research) before sending it off to the journals. What are the

Ben's blinding, plus pre-publishing

2002-06-10 Thread Jason Holt
Maybe you could say more about the details of your credential system. Such a system built on Wagner blinding might be very interesting. I've been thinking it would be nice to post my entire paper here (and maybe on sci.crypt.research) before sending it off to the journals. What are the

More of Ben's blinding

2002-06-07 Thread Jason Holt
But actually another solution is much simpler, which is to do blinding as just h * g^b, without a y factor. That works fine as long as the bank is known not to be misbehaving. Ben's paper shows how the bank can use a ZK proof to show that it is raising to the same power k every time,

Laurie's blinding w/cut and choose?

2002-06-05 Thread Jason Holt
In his paper on Lucre (2nd defence against marking): http://anoncvs.aldigital.co.uk/lucre/ Ben Laurie gives this as a (possibly patent-free) blinding technique, where h is the message, and g is the public generator: r = blind(h) = h^y * g^b (mod p) To sign, s =

Laurie's blinding w/cut and choose?

2002-06-05 Thread Jason Holt
In his paper on Lucre (2nd defence against marking): http://anoncvs.aldigital.co.uk/lucre/ Ben Laurie gives this as a (possibly patent-free) blinding technique, where h is the message, and g is the public generator: r = blind(h) = h^y * g^b (mod p) To sign, s =

Bit commitment with hashes in Applied Cryptography

2002-05-31 Thread Jason Holt
In Applied Cryptography, p. 87 (2nd ed., heading Bit Commitment Using One-Way Functions) Schneier specifies that Alice must generate 2 random bit strings before hashing, and then send one along with the hash as her commitment: commitment = H(R1, R2, b), R1 Then she sends R2 and her bit to

Re: When encryption is also authentication...

2002-05-31 Thread Jason Holt
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

Bit commitment with hashes in Applied Cryptography

2002-05-31 Thread Jason Holt
In Applied Cryptography, p. 87 (2nd ed., heading Bit Commitment Using One-Way Functions) Schneier specifies that Alice must generate 2 random bit strings before hashing, and then send one along with the hash as her commitment: commitment = H(R1, R2, b), R1 Then she sends R2 and her bit to

Re: When encryption is also authentication...

2002-05-31 Thread Jason Holt
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

Re: Making Veri$ign rich(er)

2002-05-30 Thread Jason Holt
On Thu, 30 May 2002, Ian Grigg wrote: [...] And, in practice this is how it goes. No thief ever bothers to do an MITM, even over *un*encrypted traffic. They simply hack into the machines and steal it all. That's why there has never been a case of CCs sniffed over the net and being used to

Re: When encryption is also authentication...

2002-05-30 Thread Jason Holt
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

Re: Making Veri$ign rich(er)

2002-05-30 Thread Jason Holt
On Thu, 30 May 2002, Ian Grigg wrote: [...] And, in practice this is how it goes. No thief ever bothers to do an MITM, even over *un*encrypted traffic. They simply hack into the machines and steal it all. That's why there has never been a case of CCs sniffed over the net and being used to