Re: [cryptography] Generating passphrases from fingerprints

2010-12-04 Thread Jonathan Katz
On Sat, 4 Dec 2010, Jens Kubieziel wrote: Hi, recently I had a discussion about biometric data. The following problem occured: Assume someone wants to register at a website. He swipes his finger over his fingerprint reader. The reader generates strong passphrase from the fingerprint and other

Re: [cryptography] wanted: recommendations for best papers in cryptology

2011-01-08 Thread Jonathan Katz
On Fri, 7 Jan 2011, travis+ml-rbcryptogra...@subspacefield.org wrote: Hey all, I'm attempting to create an extensive archive of papers on -graphy and -analysis, locally stored and broken down by category/hierarchy, according to my own personal taxonomy. Maybe one day I'll try to figure out

Re: [cryptography] Minimally Sufficient Cryptosystem

2011-07-05 Thread Jonathan Katz
On Tue, 5 Jul 2011, Scott Guthery wrote: Adi Shamir gave a talk at MIT last week at which I think he said that the following cryptosystem was minimally sufficient: XOR Key / Permutation / XOR Key He seemed to me to imply that (informally speaking) any additional complexity would be more

Re: [cryptography] Password non-similarity?

2012-01-02 Thread Jonathan Katz
On Mon, 2 Jan 2012, lodewijk andr?? de la porte wrote: The reason for regular change is very good. It's that the low-intensity brute forcing of a password requires a certain stretch of time. Put the change interval low enough and you're safer from them. We've had someone talk on-list about a

Re: [cryptography] Proving knowledge of a message with a given SHA-1 without disclosing it?

2012-02-01 Thread Jonathan Katz
On Wed, 1 Feb 2012, Nico Williams wrote: On Wed, Feb 1, 2012 at 3:49 AM, Francois Grieu fgr...@gmail.com wrote: The talk does not give much details, and I failed to locate any article with a similar claim. I would find that result truly remarkable, and it is against my intuition. The video

Re: [cryptography] Chrome to drop CRL checking

2012-02-06 Thread Jonathan Katz
On Mon, Feb 6, 2012 at 9:52 PM, Steven Bellovin s...@cs.columbia.edu wrote: http://arstechnica.com/business/guides/2012/02/google-strips-chrome-of-ssl-revocation-checking.ars                --Steve Bellovin, https://www.cs.columbia.edu/~smb Interesting blog post on this topic by Adam Langley

Re: [cryptography] Duplicate primes in lots of RSA moduli

2012-02-15 Thread Jonathan Katz
On Wed, 15 Feb 2012, Steven Bellovin wrote: On Feb 15, 2012, at 11:56 45AM, Ben Laurie wrote: I did this years ago for PGP keys. Easy: take all the keys, do pairwise GCD. Took 24 hours on my laptop for all the PGP keys on keyservers at the time. I'm trying to remember when this was, but I

[cryptography] looking for DES implementation in C

2012-02-16 Thread Jonathan Katz
I'm looking for a stand-alone implementation of DES in C. Can anyone point me to one (or send me one of their own)? Note: I know that there exist C crypto libraries that include DES, but I'd rather not install an entire library just to get access to DES. (For those who are curious: this is

Re: [cryptography] looking for DES implementation in C

2012-02-16 Thread Jonathan Katz
On Thu, 16 Feb 2012, Billy Brumley wrote: I pointed my students to this clean one for a course I recently ran: http://mayor.fri.uniza.sk/v731/u2/des.c Thanks -- this worked for me, and satisfied the test vectors I ran it on. No further replies are needed.

Re: [cryptography] Combined cipher modes

2012-02-20 Thread Jonathan Katz
On Mon, 20 Feb 2012, Harald Hanche-Olsen wrote: [Kevin W. Wall kevin.w.w...@gmail.com (2012-02-20 07:11:52 UTC)] So my first question: Are there ANY combined cipher modes for block ciphers that do not cause the ciphers to act as a key stream? (That seems to be cause most of the ones I found

Re: [cryptography] RSA Moduli (NetLock Minositett Kozjegyzoi Certificate)

2012-03-26 Thread Jonathan Katz
On Mon, 26 Mar 2012, Thierry Moreau wrote: Florian Weimer wrote: * Thierry Moreau: The unusual public RSA exponent may well be an indication that the signature key pair was generated by a software implementation not encompassing the commonly-agreed (among number-theoreticians having surveyed

Re: [cryptography] chaos-based cryptosystem with quantum crypto similarities

2012-09-30 Thread Jonathan Katz
On Fri, 28 Sep 2012, d...@geer.org wrote: I was asked to read this Fundamentals of a classical chaos-based cryptosystem with some quantum cryptography similarities Vidal G, Baptista MS Mancini H International Journal of Bifurcation and Chaos World Scientific Publishing Company I am not

Re: [cryptography] OAEP for RSA signatures?

2013-01-28 Thread Jonathan Katz
On Sat, 26 Jan 2013, ianG wrote: Apologies in advance ;) but a cryptography question: I'm coding (or have coded) a digital signature class in RSA. In my research on how to frame the input to the RSA private key operation, I was told words to effect just use OAEP and you're done and dusted.

Re: [cryptography] Looking for earlier proof: no secure channel without previous secure channel

2013-06-06 Thread Jonathan Katz
Isn't it obvious? (I mean, there is some value in formalizing the model, but still...) Consider authentication of A to B. If there is nothing distinguishing (impersonator) Mallory from (honest) A, then anything A can do can also be done by Mallory. On Thu, Jun 6, 2013 at 1:31 PM, Ralph Holz

Re: [cryptography] Examples of Boneh/Silverberg Multilinear Forms

2013-08-14 Thread Jonathan Katz
The Weil and Tate pairings give (cryptographically useful) *bilinear* maps. Cryptographically useful *multilinear* maps were unknown until recently: https://eprint.iacr.org/2012/610 https://eprint.iacr.org/2013/183 On Wed, Aug 14, 2013 at 11:27 AM, Scott Guthery s...@acw.com wrote: In

Re: [cryptography] The Unbreakable Cipher

2013-09-25 Thread Jonathan Katz
On Wed, Sep 25, 2013 at 10:11 AM, John Young j...@pipeline.com wrote: NSA Technical Journal published The Unbreakable Cipher in Spring 1961. http://www.nsa.gov/public_info/_files/tech_journals/The_Unbreakable_Cipher.pdf Excerpts: [Quote] David Kahn, Lyen Otuu Wllwgh WI Etjown pp. 71,

Re: [cryptography] The Unbreakable Cipher

2013-09-25 Thread Jonathan Katz
On Wed, Sep 25, 2013 at 1:30 PM, Greg Rose g...@seer-grog.net wrote: On Sep 25, 2013, at 9:40 , Jonathan Katz jk...@cs.umd.edu wrote: Every cipher is breakable, given enough traffic: in principle, yes, as long as the traffic (formally, the entropy of the traffic) is larger than the key

Re: [cryptography] RSA signatures without padding

2015-07-10 Thread Jonathan Katz
On Fri, Jul 10, 2015 at 4:15 PM, Filip Paun paunfi...@gmail.com wrote: Suppose I have a message M for which I generate an RSA-2048 digital signature as follows: H = SHA-256(M) S = H^d mod N Assume N = p*q is properly generated and d is the RSA private key. And I verify the signature

Re: [cryptography] RSA signatures without padding

2015-07-12 Thread Jonathan Katz
On Fri, Jul 10, 2015 at 7:42 PM, Filip Paun paunfi...@gmail.com wrote: Hello, Thank you for your feedback. Please see my comments below. On Fri, Jul 10, 2015 at 3:59 PM, Jonathan Katz jk...@cs.umd.edu wrote: On Fri, Jul 10, 2015 at 4:15 PM, Filip Paun paunfi...@gmail.com wrote: Suppose I