William Hird

76 reputation

bio	website	notyet;)
	location	Peacedale, RI
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Electronics Engineer, Amateur Cryptographer with interests in designing real random and psuedorandom bit generators.

"Randomness is like a box of chocolates; you never know what you are going to get"

                                                                   Forrest Gump Jr.

"You can't use mathematical means to create true randomness but you can use mathematical means to stretch a short truly random bitstream into a binary string of virtually infinite length that is indistinguishable from the uniform distribution, the distinguisher being a Universal Turing Machine". John Von Neumann Jr.

"It's trivial to make a Turing machine that fools all other Turing machines into "thinking" that they are looking at an unpredictable uniform distribution. Here is the schematic."

                                                                   Alan Turing Jr.

	76 reputation	bio	website	notyet;)	visits	member for	1 year, 9 months
6 badges		location	Peacedale, RI		seen	12 hours ago

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Apr 24	comment	Are asymptotic lower bounds relevant to cryptography? Hi Mike, I just re-read this paper again , read the last two paragraphs on page 704. Shannon never gives a mathematical proof for the security of the OTP, he only talks about the requirements of a perfect secrecy system. He shows that the OTP meets the requirements but he does not offer a mathematical proof (lower bound for the amount of work necessary to break a OTP cipher of length N) of security. Big difference, that is the P vs NP problem.
Apr 24	comment	Are asymptotic lower bounds relevant to cryptography? @Mikeazo: Hi Mike, did Shannon offer a mathematical proof that the OTP is unbreakable? Could you supply a reference to this, I guess this guy is looking for lower bounds for solving an NP problem (cryptosystem) which is of course equivalent to separating P and NP?
Apr 24	answered	Are asymptotic lower bounds relevant to cryptography?
Nov 29	awarded	Editor
Nov 29	awarded	Commentator
Nov 28	awarded	Student
Nov 16	comment	Are there practical upper limits of RSA key lengths? @Samuel: Thank you for taking the time to run the numbers!
Nov 16	revised	Are there practical upper limits of RSA key lengths? correct word here is practical, not practically
Nov 14	comment	Are there practical upper limits of RSA key lengths? Thank you, I was thinking that primality testing would be difficult for such large primes. Can you recommend any literature that explores this avenue of research?
Nov 14	comment	Are there practical upper limits of RSA key lengths? Thank you for the reply, although I don't get the connection between scientific inquiry and demonstrations of manhood :)
Nov 14	asked	Are there practical upper limits of RSA key lengths?
Sep 18	comment	Could one construct a cipher that is secure for friendly parties to use but insecure for hostile parties? I have to take issue with some of Mr. Ebermann's comments about the one time pad not being a stream cipher . I make these comments here for the sake of those who may be following this particular thread. I guess I will have to begin by asking Mr. Ebermann what his definition of a one time pad is and why the cipher system I have mentioned in this thread cannot be classified as a one time pad as is traditionally defined in the Wikipedia article on the one time pad.
Sep 14	comment	Could one construct a cipher that is secure for friendly parties to use but insecure for hostile parties? @Paulo: A "modern day" one time pad cipher uses a psuedorandom bit generator as the keystream. An m-sequence psuedorandom generator with a seed length(register length) of 100bits running at 1Ghz will generate bits for millions of years before it repeats its sequence. If I secretly send someone my 100bit key and he/she has the same crypt-decrypt algorithm as me, then we can communicate with each other with perfect secrecy at an information rate of 1 billion bits per second for millions of years using the one time pad cipher, one key bit for every bit of text.
Sep 13	comment	Could one construct a cipher that is secure for friendly parties to use but insecure for hostile parties? @e501: I can't recommend any articles off-hand, sorry, I am too busy, but I'm sure you can find lots of good stuff there!
Sep 13	comment	Could one construct a cipher that is secure for friendly parties to use but insecure for hostile parties? @Paulo: Every cryptography book I have ever read describes the one time pad as a stream cipher. Please enlighten us as to why you think it is not a stream cipher.
Sep 12	answered	Could one construct a cipher that is secure for friendly parties to use but insecure for hostile parties?
Aug 9	comment	Why isn't the alternating step generator used more often? Thank you , very informative!
Aug 7	comment	Why isn't the alternating step generator used more often? Thank you for the patent link, when I first searched for this at USPTO I typed in CG Gunther and nothing came up, I should have dug deeper :)
Aug 7	asked	Why isn't the alternating step generator used more often?