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8921  Economy / Service Discussion / Re: Guess what - Another Topic on MtGox Cash Withdrawals on: July 31, 2012, 01:01:24 AM
Does the status say processed or confirmed?
8922  Economy / Service Discussion / Re: BitFloor.com Rocks! on: July 31, 2012, 12:47:48 AM
Out of curiosity, why not?

Lets think this logically (not I wish x would happen because it helps me personally).

Why would someone use a MtGox code?  Why not just cash out from MtGox?

Someone will deposit a MtGox code because there is a long delay @ MtGox.  

If someone could cash out from MtGox with a 21 day delay or cash out from Bitfloor with a 0 day delay which would they pick?  

So you would see a huge influx of semi-worthless Gox codes.  Now when those users deposit a Gox code and attempt to cash out on Bitfloor where does the cash come from?  It is still on MtGox so the operator has to cash out from MtGox wait 21 days for it to get to his bank account and then pay users.     Quickly the cashouts will exceed cash on hand and delay for cashing out will go from 0 days to 21 days.   MtGox can then push shtylman's cashout requests to the back burners (oops this request took 28 days, that one too 32 days).   That would disrupt his cashflow probably fatally.  When Bitfloor no longer has fast cashouts it will die.  
8923  Bitcoin / Bitcoin Discussion / Re: "All cryptography is breakable" criticism on: July 30, 2012, 07:32:18 PM
Then why does the NSA hold a contest to see if anyone can find out what a file is composed of by cracking the hash?

They don't.  You likely misunderstood the intent and purpose of the contest.

Nobody not even the creator of a hash can convert a hash back to the plaintext.
All you can do it take the KNOWN SECRET hash it and compare it to the stored hash.  If they match then you have validated the secret.
8924  Bitcoin / Bitcoin Discussion / Re: "All cryptography is breakable" criticism on: July 30, 2012, 07:29:48 PM
No, I'm not talking about predicting the future. I'm saying an attacker gains access to a computer which is encrypting shit in sha-256. The sha-256 program is modded to make what is encrypted there after breakable by the attacker. Now when the encrypted material is intercepted it is trivial for the attacker to decrypt yet still appears to be valid sha-256 encryption. Maybe the code is modded so more collisions occur or some other innocuous change. If the user doesn't validate the code integrity the user will never know the mod exists.

SHA-256 is a hashing function.  There is no such concept as decryption.  There is only plaintext -> hash.  Also if an attacker has access to the computer doing the hashing couldn't they simply make a copy of the secret being hashed before it is hashed. Smiley
8925  Economy / Speculation / Re: Assuming this post is true, does Bitcoin have no limit on its value? on: July 30, 2012, 06:49:43 PM
The intent of the post quoted is being misunderstood.  The post simply deals with quantum computing and the very limited set of circumstances in which it could "kill" Bitcoin.  There are more likely threats to Bitcoin than Quantum computing.

From a big picture point of view there are three ways one could attack the cryptographic primatives used in Bitcoin:
  • Quantum computing - very unlikely to be a threat (covered in the quoted post of OP).
  • Brute force attack - there is insufficient energy remaining in our star to COUNT to 2^256 much less brute force it.
  • Cryptographic flaw in one of the cryptographic primitives (ECDSA, SHA-256, RIPEMD-160) - the most plausible attack vector.

Is there a flaw?  It can't be proven.  SHA-256 has been very extensively tested by international community and so far it has remained very resistant to attack.  ECDSA is less tested although still subject to significant scrutiny.  At a minimum we can say no easily exploitable flaw has been found.  Now does a flaw mean "insta-kill bitcoin"?  No.  Most flaws tend to fall under the category of "only interesting to academics".  

SHA-256 (and SHA-512) has a cryptographic flaw.   Huh  WTF?  Yup right here:
http://eprint.iacr.org/2009/479.pdf

There is no economic value to this flaw.  However it "could" (eventually) lead to more "practical" attacks in the future.  

So what happens if SHA-256, RIPEMD-160 or ECDSA becomes "cryptographically weak"?
Well if they became weak enough one could attack private keys at a rate faster than an exhaustive brute force search.   Existing addresses would be vulnerable (at least in theory) however Bitcoin as designed to be modified.  Miners by consensus agree to a protocol enhancement which allows creation of addresses based on new cryptographic primitives (much like how Bitcoin now supports sending coins to addresses which are the hash of a script "pay to script hash"). So some future version of Bitcoin would continue to provide LEGACY support for existing addresses AND provide support for new addresses.  The timelines on cryptographic flaws tends to be measured in years so there would be extensive time to deploy a new version, and allow users to transfer coins from old "vulnerable" addresses to new "secure" addresses.  

If eventually ECDSA, SHA-256, or RIPEMD-160 becomes so degraded an attacker may be able to mine older "vulerable" addresses to steal the coins.  Users would have an incentive to upgrade their clients and move coins to newer "secure" addresses.

It is important to understand that even if we moved to a new algorithm as a precaution it might never be possible to use any flaw in practical manner.  I will give you an example.  A flaw has been discovered in SHA-1 which allows a pre-collision attack at 10,000 faster than brute force.  Sound horrible right?  Not really.  If such a flaw existing for SHA-256 it might mean you would have a 1% chance of attacking a private key in the next billion years (instead of 0.00001%).   Still as a precaution (more against future deeper flaws) it would be prudent to enhance the protocol to support newer address types.

Would a flaw in SHA-256 fatally damage the mining aspects of the network?
Under all probable scenarios no.  A round reduction attack would simply make miners more efficient (i.e.a GPU that runs at 1 GH/s might now compute at 520 TH/s).  Since difficulty is simply an arbitrary value it wouldn't really matter.  The nominal difficulty of the network would rise but miners with upgraded software/firmware would simply miner at a higher rate.  1% of network hashing power would still be 1% of network hashing power.  The one exception would be ASICs.  Since they can't be upgraded they would be a competitive disadvantage to both future ASICS (optimized to exploit any flaw) or programmable miners (CPU/GPU/FPGA).  Now granted ASICs are so much more efficient, that any disadvantage might only be academic at best.  

TL/DR version:
1) The post quoted dealt with quantum computing not SHA-256 invulnerability.
2) SHA-256 "may" be degraded someday.
3) Any attack on SHA-256 is likely to take a long time to develop and that will give the community time to upgrade.
4) The Bitcoin protocol can be enhanced to support new "strong addresses" while retaining legacy support for older "vulnerable" addresses.
8926  Bitcoin / Bitcoin Discussion / Re: PrismCoin: 3d etching BTC address in Crystal on: July 30, 2012, 06:23:54 PM
If you want a lasting material go with tungsten.

Melting point is significantly higher than structure fires, it is non reactive in most environments, and has high toughness.

8927  Bitcoin / Bitcoin Discussion / Re: "All cryptography is breakable" criticism on: July 30, 2012, 04:59:06 PM
OK. I'll explain. SHA-256 is used for hashing. Of coz it's used in a variety of applications. But if someone get a quantum computer and manage to falsify a digitally signed contract then only authentic owner of the contract will be harmed. If someone manage to falsify an SSL certificate then only visitors of the site will be harmed. But if someone manage to find block nonces every second, then everyone who uses bitcoins will be in troubles.

Quantum computers aren't  a magic bullet.  Yes using Shor's algorithm the search speed can be increased exponentially however at what cost?   For example say once ASICs become mainstream the cost to attack/defend the network using ASICs is $20,000 per TH.  Now say a quantum computer which could implement shor's algorithm on 256bit numbers could be built for $50,000 per TH equivelent.  Who cares?  An attacker is going to take the more economical option.

So quantum computer is only a threat if all 5 elements are true
a) it is possible to build a quantum computer which can implement shor's algorithm on 256bit numbers
b) it is possible to build a quantum computer large enough to 51% attack the network
c) it is possible to build a quantum computer that makes such attack more economical than ASIC based brute force
d) quantum technology can be restricted so that a computer meeting requirements a,b, c isn't available to "defenders"
e) Bitcoin protocol isn't changed to implement quantum resistant block hashing algorithm

The idea that a,b,c,d & e will all remain true at the same time is implausible.  a & b are technical limitations and currently impossible although they MAY be possible in the future.  c is likely only true if quantum computers are being mass produced.  If c is true then it is very likely d isn't true.   a,b,c &d aren't going to happen overnight so as implausible as that set on conditions is some years or decades before it becomes true Bitcoin could adopt a quantum reistant hashing algorithm making conditon e false.
8928  Bitcoin / Bitcoin Discussion / Re: "All cryptography is breakable" criticism on: July 30, 2012, 04:46:42 PM
Couldn't an attacker replace unknown inputs/variables with known inputs/variables, then all of the targets data which uses encryption from that point forward would be breakable by the attacker?

You mean predict the future?  The inputs will be unknown until they are known. 

What the the prior block has for block 500,000?  Everyone will know once block 499,999 has been accepted by the network but there is no way for the attacker to predict the future and make the unknown inputs for block 500,00 known today.
8929  Bitcoin / Bitcoin Discussion / Re: "All cryptography is breakable" criticism on: July 30, 2012, 04:07:10 PM
The rest of the world will be fine, coz they use SHA-256 only for signing.

Is a false statement.  SHA-256 is used in a variety of applications.
8930  Bitcoin / Project Development / Re: Is there a wallet that can schedule transactions? on: July 30, 2012, 04:52:43 AM
example instead of having to wake up in the middle of the night if you owe someone a payment, have it scheduled to send out, leave the wallet unprotected so funds are stolen before you wake up, maybe even as soon as the funds are available.

FYPFY.  The answer is no and it probably a good idea.  What you are describing is a hot wallet and every major hack/theft of bitcoins involved a hot wallet (from MyBitcoin to Bitcoinica).
8931  Bitcoin / Bitcoin Discussion / Re: NFC - The QR Code Killer on: July 29, 2012, 09:41:36 PM
My belief is yes but we are two to three years away from mainstream adoption.  It is going to be pushed for CC usage but once the hardware (both consumer & merchant) is nearly universal Bitcoin can piggy back off that. 

I have been playing around with a pair of Samsung Galaxy Nexus smartphones.  The tech is trivial to use and will become standardized on android (much like you can't find a smartphone without a camera or GPS in 2-3 years you won't be able to find a smartphone without NFC).

The nice thing about NFC is it provides a platform where you can transmit dynamic content easily.  There will never be a "swiped" Bitcoin card and today that is nearly universal this makes supporting Bitcoin expensive in terms of custom hardware.  You aren't going to see widescale meatspace adoption if merchants can't easily integrate it.  When NFC replaces swiped cards the same hardware can transparently support Bitcoin.  There is no reason to not accept Bitcoin (unless as a merchant you dislike lower fees and no fraud).
8932  Economy / Currency exchange / Re: TheBitMint - Buy Bitcoins With PayPal on: July 29, 2012, 06:07:54 PM
So you agree that the people have joined a class of people that are allowing one member to file a claim against TheBitMan's parents, and you feel the need to be a pedantic prick, and correct me calling it class action crap...

It isn't a class action lawsuit.  That requires certification as a CLASS.  Your use of the word "class" is confusing given a lawsuit is a legal action and the term "class" has a specific legal meaning. Only a judge can certify a group of claimants as a class.  So someone correcting you that it isn't a class action lawsuit is simply being factual.

The proposed legal action would be a claim in small claims court.  There wouldn't be a class there would be a single claimant and one (or possibly two) defendants.  Any agreements between other creditors and the filing claimant would have no bearing in the case.
8933  Other / Beginners & Help / Re: Paypal BTC purchase avail on: July 29, 2012, 05:56:32 PM
LOZ.  Another 1 post wonder.  Where did you find him "over the past few months"?

Honestly anyone who falls for this scam probably deserves to get scammed.
8934  Economy / Currency exchange / Re: TheBitMint - Buy Bitcoins With PayPal on: July 29, 2012, 05:54:58 PM
so the 5 participants have agreed to join the class of people taking TheBitMan to small claims court?

I think everyone including BCB is willing to see if TheBitMan can secure a loan.  I would also point out TheBitMan didn't begin looking for a loan until talk of a lawsuit started.  My guess is that TheBitMan's parents could pay this debt and get reimbuses in 180 days (even if it required using a credit card cash advance) but likely they know nothing about it.  My guess is that TheBitMan doesn't want them to learn about his PayPal adventures.  A lawsuit would certainly make his parents aware.  If TheBitMan secures a loan and everyone is repaid then there is no need for a lawsuit to go forward.  If he can't secure a loan, he can get his parents to advance the funds.  If he is unwilling to do either a small claim lawsuit will force the issue and also protect the interest of the creditors.
8935  Economy / Currency exchange / Re: FastCash4Bitcoins - Support Thread on: July 29, 2012, 03:32:02 PM
See the problem is I need a cc, which I have but is closely monitored by my parents. Kickstarter doesn't charge until the end date if the threshold is met. The only caution I have is that make sure you have enough credit to pay for all applicably kickstarter funds due.

I looked and there is no method I could fund a kickstarter account however kickstarter uses amazon payments.  I will look into paying out into an amazon payments account.  So for example you could sell 10 BTC, get $85 paid into your Amazon payment account and then use that to pay kickstarter.
8936  Economy / Auctions / Re: bitcoindevices.com available on: July 29, 2012, 02:07:21 PM
0.11000001 BTC

probably. Smiley
8937  Bitcoin / Press / Re: 2012-07-27 betabeat.com - Australian Law Enforcement: Use Silk Road At Your Peri on: July 29, 2012, 03:48:30 AM
Since when do cops warn potential criminals to ensure they aren't arrested by their foolproof sting?

My guess is if Australian police were that effective at catching SR users they wouldn't say anything and just let the thousands of arrests pile up before announcing the massive "victory" in the "war on chemical compounds which are organized into structures deemed undesirable by authorities".  One person was arrested and there is no evidence that SR, TOR, or Bitcoin had anything to do with that arrest.  It could be anything from the guy was an idiot and talked too much  to he had bad luck and one of his "packages" was damaged enroute alerting the authorities.

 
Note: D&T isn't responsible if I am completely wrong and you end up getting busted. Wink
8938  Economy / Currency exchange / Re: FastCash4Bitcoins - Support Thread on: July 29, 2012, 01:32:42 AM
Could you add kickstarter?

Does kickstarter allows depositing funds directly into a user's account?
I will certainly take a look.

On edit:  I don't see any user to user transfer mechanism for Kickstarter.  Kickstarter pledges are funded by amazon payment so we could look into offering payouts using that platform.
8939  Economy / Currency exchange / Re: TheBitMint - Buy Bitcoins With PayPal on: July 29, 2012, 12:18:45 AM
idk if theres something im not getting but if i refresh the page and enter the same address I get a different hash..

I find that hard to believe.  Hashing functions always return the same output.  Make sure you are hashing the EXACT same value. As an example, "test " won't produce the same hash as " test" or "test" however the SHA-256 hash of "test" will never change. The SHA-256 hash of "test" (without quotes) will ALWAYS be:

Quote
9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08

The link provided is just one calculator, you can always use another one. Baring a flaw in the calculator the hash of an input will always be the same.   Bitcoin simply wouldn't work if SHA-256(x) wasn't always the same value.
8940  Other / Beginners & Help / Re: what's the fastest way I can purchase a large amount of bitcoins? on: July 29, 2012, 12:12:40 AM
Tangible Cryptography LLC can supply wholesale bitcoins however our volume is  roughly 1,000 to 1,500 BTC per day so it will take a few days to handle an order of that size.  Price is @ MtGox last with no fees or slippage.  If funded by a bank wire or bank deposit you can have your first batch of coins the same day.  As a new customer you will be limited to a maximum of $5,000 on your first transaction.  We can give you a 1% discount below MtGox on subsequent purchases if part of a larger deal.  

https://bitcointalk.org/index.php?action=profile;u=57640

Setup GPG, import our company private key, and send us a test message.  We would be happy to discuss your options.
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