- cypherpunks-legacy - lists.cpunks.org

Adv (adlt) : Make it a C*CK BUSTER NIGHT!
by Sheila 19 Oct '02

19 Oct '02

1 0

Re: eating dirt, and loving it, in MD
by Dean, James 19 Oct '02

19 Oct '02

The next time your on the streets with a lot of people, look around. You'll probably see a number of white vans. The idea that the sniper is using one is probably bogus.

1 0

hot sexy sluts ivw
by Sandra* 19 Oct '02

19 Oct '02

1 0

Independence and redundncy Re: XORing bits to eliminate skew
by Sarad AV 19 Oct '02

19 Oct '02

hi, One more query on the same topic. >Now add a second bit. assume that the bits are (i) > and (ii) so we know > that the probability of (i) being 1 is 0.5-e and and > being 0 is 0.5+e > (there isn't a bias btw in that notation - e could > be negative) > > so all the possible combinations are > > P(i=1, ii=1) =(0.5-e)(0.5-e) > P(i=1, ii=0) =(0.5-e)(0.5+e) > P(i=0, ii=1) =(0.5+e)(0.5-e) > P(i=0, ii=0) =(0.5+e)(0.5+e) Two events E1 and E2 are said to be independent,if P(E1(intersection)E2)=P(E1).P(E2) As in the above case we assume that the bits under xor are independent. if the inputs are frm different sources then we consider them independent. what about the following case. i open any two text files in binary mode and xor 1 st bit of file 1 with file 2,2 nd bit with 2 nd bit with second bit and so on. The rate of english varies between 1.0 bit /letter & 1.5 bit/letter for large values of N. absolute rate of english is R=log(26)base 2=4.7 bits/letter There is lot of redundancy in the language,0.6 to 0.85 percent redundancy. Since in ASCII we use 8 bits to represent english alphabets,the redundancy is 8-1.3=6.7 bits/charecter of redundancy. Since in both files opened,english charecters are represented in the same set of ASCII charecters. there is redundancy in both the files. Does that mean that such bits we xor are not independent? Regards Sarath. --- David Howe <DaveHowe(a)gmx.co.uk> wrote: > at Thursday, October 17, 2002 4:38 PM, Sarad AV > <jtrjtrjtr2001(a)yahoo.com> was seen to say: > > He wanted to know how I was able to do XOR on P(0) > and > > P(1) when xor is defined only on binary digits. > you don't. > > P(x) is a probability of digit x in the output. > ideally, P(0)=P(1)=0.5 > (obviously in binary, only 0 and 1 are defined, so > they are the only two > possible outcomes. > Now assume that one output (1 say) is more probable > than the other. If > this is true, you can define some value of > probability (e) that is the > amount a given outcome is more or less probable than > the ideal. > Now add a second bit. assume that the bits are (i) > and (ii) so we know > that the probability of (i) being 1 is 0.5-e and and > being 0 is 0.5+e > (there isn't a bias btw in that notation - e could > be negative) > > so all the possible combinations are > > P(i=1, ii=1) =(0.5-e)(0.5-e) > P(i=1, ii=0) =(0.5-e)(0.5+e) > P(i=0, ii=1) =(0.5+e)(0.5-e) > P(i=0, ii=0) =(0.5+e)(0.5+e) > > but of course if you XOR (i) and (ii) together, then > (i=1, ii=1) = 0 > (i=1, ii=0) = 1 > (i=0, ii=1) = 1 > (i=0, ii=0) = 0 > > collecting identical outputs allows you to say > > P(0)=P(i=1, ii=1)+P(i=0, ii=0) = > (0.5-e)(0.5-e)+(0.5+e)(0.5+e) > P(1) P(i=1, ii=0) + P(i=0, ii=1) = > (0.5-e)(0.5+e)+(0.5+e)(0.5-e) > > reducing P(0) as in the example you gave gives you > the probability of > P(0) being 0.5+(2*(e^2)) > > so the answer is - you don't ever apply XOR to > anything but binary - you > do straight algebraic math on the *probabilities* of > a given output (0 > or 1) > __________________________________________________ Do you Yahoo!? Y! Web Hosting - Let the expert host your web site http://webhosting.yahoo.com/

1 0

网易分类信息（山东）招商
by classadmaster＠163.com 19 Oct '02

19 Oct '02

ÕâÊÇÒ»žöHTMLžñÊœµÄÓÊŒþ/This is a html format mail

1 0

edeb
by hsvcSandee 19 Oct '02

19 Oct '02

1 0

Re: One time pads
by Bill Stewart 19 Oct '02

19 Oct '02

At 12:16 PM 10/17/2002 -0700, Morlock Elloi wrote: >I have a working OTP system on $40 64 Mb USB flash disk on my keychain. Cute. Is it available? How do you prevent other applications from reading the file off your USB disk, either while your application is using it or some other time? That's one of the big differences between a computerized OTP and a Dead Trees (or Dead Silkworms) OTP, which is much harder for someone or something else to read without you noticing. Since you say that "Used bits are securely deleted", does your application distinguish between using the pad to encrypt and using the pad to decrypt (which are basically the same thing, except for destroying the key bits the second time)? >30Mbs are filled with distilled randomness (two video digitizers at high gain >looking into open input noise, compressed first with LZW then again compressed >8:1 by taking only byte parity, then XORed together - takes several hours and >passes diehard) Landon Noll has done some interesting work taking a cheap PC camera and keeping it in the dark. The CCDs try to adjust, and you get noise. Rather than compressing 8:1 using byte parity, I'd recommend using a hash function, such as MD5 or SHA, which means that every bit of the input can tweak any bit of the output. >judging by the current use it will last us for decades for text messages. That's the Bic Pen model of "you'll lose it before you use it up" :-) If you're using it strictly for session key exchange, that's a lot of sessions (unless you're a big web or email server.) If you're using it for message encryption, it's obviously not much.

3 4

Re: One time pads
by Bill Stewart 19 Oct '02

19 Oct '02

At 02:04 PM 10/17/2002 +0200, Eugen Leitl wrote: >It is important to note that currently NMR bases systems only allow for >6 qubits. Only very recently we're getting practical qubits in solid state. >..... >Everybody realizes that we're discussing currently completely theoretical >vulnerabilities, right? Of course. But without quantum computing, you can do computations on your basic cheap computers that are secure against crackers for the expected remaining life of the universe, so your threat models are much more controllable. Obviously you still need to worry about tempest, computer viruses, cameras in the ceiling, and rubber hose cryptanalysis, but threat models that just involve someone intercepting your message aren't a problem. Quantum computing is the one thing that anybody's thought of that has a mathematically possible chance of breaking that.

1 0

URGENT RESPONSE NEEDED
by MARCUS GARVIN 19 Oct '02

19 Oct '02

ATTN: SIR. I PRESUME THIS EMAIL WILL NOT BE A SURPRISE TO YOU. I AM AN ENGINEER WITH THE MINISTRY OF MINERAL RESOURCES AND ENERGY IN SOUTH AFRICA AND ALSO A MEMBER OF CONTRACTS AWARDING COMMITTEE OF THIS MINISTRY UNDER SOUTH AFRICA GOVERNMENT. MANY YEARS AGO, SOUTH AFRICA GOVERNMENT ASKED THIS COMMITTEE TO AWARDS CONTRACTS TO FOREIGN FIRMS, IN WHICH, I AND TWO OF MY PARTNERS ARE THE LEADER OF THIS COMMITTEE, WITH OUR GOOD POSITION IN THIS COMMITTEE, WE OVER INVOICED THIS CONTRACTS TO THE TUNE OF US$21,500,000:00, TO BE BENEFITED BY ME AND TWO OF MY PARTNERS THAT ARE INCHARGE OF THIS CONTRACTS AWARDING COMMITTEE OF THIS MINISTRY. NOW, THAT THE CONTRACTS VALUE HAS BEEN PAID OFF TO THE ACTUAL CONTRACTORS THAT EXECUTED THIS JOBS, ALL WE WANT IS A TRUSTED FOREIGN PARTNER LIKE YOU THAT WE SHALL FRONT TO MAKE THIS OVER INVOICE SUM. UPON OUR AGREEMEENT TO CARRY ON THIS TRANSACTION WITH YOU, THE SAID FUND WILL BE SHARE AS FOLLOWS. 75% WILL BE FOR US IN SOUTH AFRICA. 20% FOR USING YOUR ACCOUNT, 5% WILL BE SET ASIDE FOR THE UP FRONT EXPENCES THAT WILL BE ENCOUNTER BY YOU AND US TO PROCESS ALL NECESSARY DOCUMENTS AND FORMARLITIES THAT WILL JUSTIFY YOU AS THE RIGHTFUL OWNER OF THIS FUND. YOU SHOULD BEAR IN MIND THAT YOU WILL BE REQUIRED TO PUT HEADS WITH US TO GIVE THIS TRANSACTION MORAL AND FINANCIAL SUPPORT IT REQUIRED TO BE SUCCESSFUL. ATTN: IF YOU ARE INTERESTED AND FINANCIALLY CAPABLE TO HANDLE THIS TRANSACTION, KINDLY REPLY US THROUGH THIS EMAIL ADDRESS(parkkinsen6(a)netscape.net) FOR MORE DETAILS AND WHAT IS REQUIRED OF YOU IN THIS TRANSACTION. ALSO WE REQUEST FOR YOUR PRIVATE AND OFFICE PHONE NUMBERS TO OPEN COMMUNICATION WITH YOU. YOURS FAITHFULLY. GARVIN MARCUS. N:B AM PRESENTLY IN HOLLAND FOR THREE MONTH COURSE, YOU CAN ALSO REACH ME WITH MY DIRECT TELEPHONE NUMBER, 0031-613-866-336.

1 0

Re: Intel Security processor + a question
by Tyler Durden 19 Oct '02

19 Oct '02

Well,I disagree about psuedo random number generation, sort of. First, if I have PSR sequence of the known variety (ie, ANSI or ITU), and if it's mapped to some telecom standard (DS-1/3, OC-3/12/48/192), then my test set can and should be able to lock onto that sequence. This is true whether that telecom signal is raw PRBS, or if it has been mapped into the payload (you use different test sets). In addition, PRBS have a very distinctive trace signature in the frequency domain. SO if I run my PRBS-mapped telecom signal into an O/E (if it's optical, for instance), and then into an Electrical Signal Analyzer, I'll be able to see if the characteristic Electrical Frequency spectrum matches that expected for, say PRBS-23.If it doesn't, I know something's up. If it does, it CAN of course be something else, but that signal does have the right amount of entropy. With encrypted info who knows? I would think that testing if there's monkey business might boil down to algorithms--ie, if certain bit patterns happen too often, then something's wrong... >From: "Major Variola (ret)" <mv(a)cdc.gov> >To: "cypherpunks(a)lne.com" <cypherpunks(a)lne.com> >Subject: Re: Intel Security processor + a question >Date: Fri, 18 Oct 2002 14:33:15 -0700 > > > From: "Tyler Durden" <camera_lumina(a)hotmail.com> > > Subject: Re: Intel Security processor + a question > > > > OK...a follow up question (actually, really the same question in a >diferent > > form). > > > > Let's say I had a crypto chip or other encryption engine, the code of >which > > I could not see. Now what if someone had monkeyed with it so that >(let's > > say) the pool of prime numbers it drew from was actually a subset of >the > > real pool that should be available for encryption. Let's also say that > > > "somebody" knows this, and can search byte streams for known strings >of > > products of these primes. They can then break this cypherstream very >easily. > >Or consider someone who sells a "RNG" but won't let you examine it >physically... >(you might have been sold a long-sequence PRNG, and without either 1. >the algorithm & key >or 2. physical inspection of the circuit YOU CAN'T TELL. ) > > > Now don't get hung up on the details of what I'm saying here...I don't >know > > if this particular example is possible or not. > >Of course. If you can't disassemble the code, or chip, you're fucked, >since you're trusting those who made and distributed the artifact. > >I'm just wondering iF it is > > possible to tamper with crypto code (particularly as embedded on a >chip) so > > that it appears to all regular users not to have been tampered with, >but > > meanwhile it allows certain privileged users to access encrypted >streams > > fairly easily. > >if ( !strcmp("backdoor", password_str)) let_me_in(); > >is readily written in RTL and a comparator is not many gates. > > > AND if this is possible, is there some way to examine the encrypted >output > > and then, say, search for unusual frequency traces of certain >sequences, and > > determine tha the code has been tampered with? Or are there ways to >tamper > > with good cryptocode in ways that can never be detected with actually > > looking at the originating code? > >You can write clear code --in C or Verilog-- which does not permit much >room for hidden functionality. However if you can't examine inside the >box, it is very very >easy to design backdoors you will never find in a thousand years. _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963

2 1