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1  Bitcoin / Bitcoin Technical Support / Need analysis on possible hack on: March 08, 2015, 12:36:37 AM
I just lost over 2.5 bitcoins.

I used an Android wallet, which I do not want to name just yet, pending the developer's response to the situation.

With the wallet, I generated the new address  1Bn9ReEocMG1WEW1qYjuDrdFzEFFDCq43F then sent 2.57386667 btc from localbitcoins to that address, which is txid 47b689d108a33c05405332169d3a0eb96ded33ce711fcd498ead1ba5e2b72328.   This is the only transaction that I initiated with this address.

Later, when planning to move the money to paper wallets, I discovered that this address had previous activity on it, and that most of the money was swept from that address after my transaction confirmed.  There are several transactions afterwards which sweep the remaining money out of that address.

I suspect either that this problem is due to a collision from a poor PNR, or it was a malware attack.

Anyone with insight on tracing btc transactions want to comment?
2  Economy / Economics / Semantics of "fiat" on: February 07, 2015, 05:55:40 PM
It seems to me that many bitcoin proponents use the word "fiat" to describe central bank issued fiat currency, but don't use the word to describe Bitcoin.

In my opinion, Bitcoin is the ultimate fiat currency, since it has no inherent value (you can can't use it for anything other than paying someone else bitcoin).  It is a currency issued by "decree" through a protocol enforcing a consensus of users and miners.

If bitcoin is not fiat, can you really call it a commodity currency?   If the argument is that is a commodity in the sense that it valuable a currency, one could also say that USD has commodity value in that its only guaranteed value is that it can be used to pay taxes and keep an American taxpayer out of jail for failure to do so.

3  Economy / Economics / BTC futures market? on: January 21, 2015, 02:20:22 AM
One of bitcoin's biggest problems is its price volatility. 

Also, because of volatility, bitcoin mining is a more speculative investment/business than btc/fiat currency trading.

If a futures contract market were to develop for purpose of reducing risk in investing in equipment in BTC mining, would this help to stabilize the USD price of BTC?

Would a futures market move the more speculative BTC investors, who are addicted to (and likely cause) the current volatility of BTC, into trading futures rather than BTC?
4  Economy / Service Discussion / ZipZap back in the bitcoin business? on: April 03, 2014, 08:06:00 PM

I noticed a new external link in my blockchain wallet.   It appears that ZipZap is getting back in the bitcoin business, and replacing the hole left by

5  Economy / Economics / The Attacker Index on: March 30, 2014, 10:15:09 PM

   H = current network hashrate
   M = cost per TH/s
   C = market cap of bitcoin

The attacker index (my invention) would be:

   A = (H*M)/C

which represents the percentage of the market cap needed to purchase enough hashing power to get 50% control the network.

Using current numbers,

   H = 45,000 TH/s
   M = $3000 per TH/s
   C = $5.7 billion

This number is 2.4%.    This seems to me to be too low, thus too easy to launch a 51% attack.   What would be a comfortable number?

Here is my concern:  to control a corporation, you need to own more than 50% of the shares.   To control bitcoin, you currently need only 2.4% of the bitcoins in existence
6  Bitcoin / Development & Technical Discussion / Scripting library? on: March 26, 2014, 03:02:44 AM
Here's what I want to do:

I want to write a script that runs a secure computer that generates pairs of bitcoin addresses and private keys; a manageable amount like 1000.

I want the script to write two files, one with just the addresses, and the other with both that is stored securely.

The idea is to upload the pool of addresses to a web server, and a present each customer with a unique bitcoin address to send payment.   When the order is received, the corresponding private key is imported into a hot wallet under supervision, then swept into a cold-storage address.

I'd like to reseed the PRNG between each iteration with hashed data from a random source such as a freshly recorded audio file or jpg image that is later destroyed.

I'd like to write my script in Perl, but any common scripting language would work.  Is there a trusted/good set of libraries to do this?
7  Bitcoin / Legal / IRS says btc is property, what does this do to the taint issue? on: March 25, 2014, 09:25:46 PM
Ok, so the IRS says bitcoin is property.

Does this legal definition carry over to declaring an amount of bitcoin as stolen property?

i.e., a merchant accepts btc as payment in good faith, but can be later shown to be in possession of stolen "property" and forced to return it?

Will we have to wait for a court ruling on such a matter to establish precedence?
8  Economy / Goods / [FOR SALE] Wear Your Wallet: PAY ME BTC QR Code T-shirt on: March 25, 2014, 12:35:50 AM
Get a customized PAY ME BTC T-shirt with a scannable QR code with one of your bitcoin wallet  addresses.  Anyone with a mobile device that has a bitcoin wallet that can scan QR codes can easily scan your address and send you some bitcoin.  

It's a great way to start up a conversation about bitcoin and take payments or donations wherever you are.   Street musicians could busker in a high tech area, and take tips in bitcoin.

The Pay Me BTC T-Shirt is printed on a white, preshrunk 100% cotton Gildan short-sleeved T-Shirt.   Currently available in unisex S, M, L and XL.   Your custom shirt is printed on high-quality fabric transfer paper on a color laser printer, and applied with a high temperature heat transfer press.   The QR code is encoded with the highest level of error-correction.

The design is 8 inches wide.  Using the back camera of a Samsung Galaxy Tab 3,  the image is easily scannable from 2.5 to 5 feet away.

The Pay Me BTC T-Shirt is available for the price of 49 mBTC (0.049 BTC) postpaid shipped to the USA or Canada or 59 mBTC (0.059 BTC) for other destinations.  Prices may change if the exchange rate changes drastically.  No other form of payment is accepted.

Please email or PM me:
1) A valid bitcoin address to be coded and printed on the shirt.  Please double check this address!
2) The size of the shirt: unisex S, M, L or XL.
3) Delivery mailing address.
4) Your contact email address.

I will message you back with a payment address.   Do NOT use the one shown in the graphic.  Once payment is received and confirmed, I will print/transfer and mail your shirt within 1-4 days.

Escrow is welcome with reputable escrow agents.  I can be reached by email at Website coming soon.

Version: GnuPG v2.0.17 (MingW32)

9  Bitcoin / Bitcoin Technical Support / Why would a transaction need multiple inputs from the same address? on: March 22, 2014, 06:22:43 AM
I have an imported address in my blockchain hotwallet.   It came from a paper wallet that was loaded with one transaction.

As it lived in my hot wallet, it was used for several send transactions that were less than the amount on the address.   The transactions that the blockchain wallet formed used the entire amount on the address as the single input, and sent the desired amount to the receiver as the first output, then on the second output, sent the change back to the input address.

There were several small transactions receiving funds.

On the final transaction, draining this address, blockchain generated a transaction that had inputs from 4 different address in my wallet, however, in made 5 different inputs to the transaction using amounts from earlier receive and change output from previous transactions.

The final transaction triggered a double miners fee because of the size.

Was there any technical reason why a transaction needs 5 different inputs from the same address?
10  Bitcoin / Bitcoin Discussion / If Bitcoin Remains Impractical, Treasury Will Let It Be on: March 18, 2014, 09:16:26 PM

Bitcoin will become a bigger concern to regulators at the Treasury Department only after it becomes a truly useful currency. That was the message delivered by David Cohen, under secretary for terrorism and financial intelligence, at a speech on Tuesday morning at Bloomberg headquarters in New York.
11  Bitcoin / Development & Technical Discussion / Is there a bluetooth protocol for bitcoin transactions? on: March 18, 2014, 06:12:23 AM
Is there a standard bluetooth protocol for bitcoin transactions?

If not, there probably should be before it becomes a tower of babel.   While using QR codes is fine in most situations, it would seem there might be an advantage if the sender could transmit a copy of the signed transaction so that the receiver could broadcast the transaction to the network, in the case where the sender is unconnected to the public network.
12  Bitcoin / Legal / Mizuho Bank added as a defendant to lawsuit against Mt. Gox on: March 16, 2014, 06:56:22 AM

Is there precedent for this?   It disturbs me that the bank would be held liable, since the implication is that a bank must intensely scrutinize your business because they will be held liable, sort of like blaming ISP's for enabling sharing of copyrighted material by their customers.   It will give the banks another reason to avoid bitcoin-based businesses.

13  Bitcoin / Bitcoin Discussion / Bitcoin's killer app: Online Auctions and Escrow Service? on: March 15, 2014, 05:57:30 PM
It seems to me that a bitcoin-based auction site would be a killer app for bitcoin.

Obviously, eBay/PalPal currently has this market locked down.   However, I think that the eBay/PayPal system is designed to be over-protective of the consumer, I think it is ludicrous that a buyer can claw back a payment from a seller a year later.   With a payment system that soft, it's a wonder that any seller sells at eBay.

How hard would it be for a bitcoin-based auction site to start eating into eBay's business?  Such a site would not be able to compete with eBay/PayPal's level of consumer protection,  but could provide an escrow service and build a sterling reputation of being a fair arbiter of disputes - but ends with All Sales Final when escrow is released.

Would sellers be attracted to such a site, and would buyers follow?
14  Bitcoin / Bitcoin Discussion / Congressman Calls To Ban U.S. Dollar In Response To Plea For Bitcoin Ban on: March 12, 2014, 01:08:05 AM

Not all of 'em are stupid.

15  Bitcoin / Legal / tax liabilities on a bitcoin-only business arrangement? on: March 08, 2014, 02:13:48 AM
Assume the following business arrangement:

A fund is established for investors to pool funds for the purchase of a bitcoin mining rig.   Investors contribute bitcoins to the fund.

The mining rig is purchased in bitcoin and delivered to an operator.  Any remainder of the fund is redistributed back to the miners according to share.

The operator runs the rig.  Profits from mining are pooled into a fund.

Periodically, this fund pays the operator a reimbursement in bitcoin using current exchange rates that compensates the operator for the electricity and any other overhead, plus a commision from the net profit.

The remainder of the net profit is distributed to the investors according to share.

This operation continues until the mining rig is no longer profitable to run.

So in this arrangement, would it be sufficient for investors to pay their tax liability as capital gains from when they convert their bitcoins from and to USD?

Would the operator have to pay a tax liability?  (As a business that accepts the bitcoin reimbursement as gross income, then deducts the overhead costs for electricity and other overhead?)

Assume USA jurisdiction, but discussion of other tax jurisdictions is welcome.

16  Economy / Service Discussion / analysis on Shared Coin? on: March 04, 2014, 08:37:55 PM
Has there been discussion on how an analyst would be able to trace transactions through Shared Coin?

It seems to me that the weakness in Shared Coin transactions is that the type of transaction on the blockchain per iteration would be fairly unique (multi-sig, multiple inputs/outputs)

If an analyst wanted to connect a payment from a wallet to a payment address,  the analyst (with code) could form a tree of SharedCoin transactions starting with the final payment transaction, to a
large number of input addresses that connect to a Shared Coin transaction that is no more than 10 nodes removed from the final payment. (the maximum number of Shared Coin iterations)  In reality, all of these transactions would be close together in time, most likely end up in the same block.   

Assume the analyst has knowledge of the source address(es) and the address used to receive change in the transaction, thus knowing the amount.  Is it easy to determine that the transactions are connected if the amount of the transaction is non-trivial?

Even without knowledge of the input amount, wouldn't the number of suspected input addresses be manageable for higher scrutiny by the analyst?  (traceable to a withdrawal from a FineCEN-compliant institution linked to your identity)

I personally like the idea of Shared Coin, but I'd really like to know how much anonymity is being gained by using it.

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