What if the "offline" PC is only a passive listener in a network, e.g. WLAN?

That way, it would simply sniff network traffic until a certain transaction flies by that it could sign - it would sign it and store the signed transaction.
No bandwidth issues there and since no sending communication is allowed, there's no way that an attacker can do anything else than let it sign a transaction - something that's possible with any other method too. No way to get to the private keys though.

To get back the signed transactions (or even just the signatures, if you need to transmit even less data) you just select the ones to export and transfer them to the online machine using a write-once medium (e.g. QR code on paper, CD-R, morse code over the air...).

Using the "selective listener" approach, you just need to broadcast unsigned transactions in your network and they will be picked up and to get the signature, you'll get seomthing from the secure station that has never been in any other computer, so no way for infected USB sticks that get transferred between 2 PCs. The attack vector then would be that the secure station's network interface can be taken over/infected by passively listening to (potentially pre-filtered to only contain Armory relevant traffic by a hardware firewall) transaction data.

You take something that's normally nearly indistinguishable (e.g. 1 USD bills) and arbitratrily declare some of that "special", "tainted" or "colored".

For example I have a 1 USD bill with the serial number 1234567890 and I declare that I will give anyone who hands me this exact bill in the future 100 USD, then I spend it/auction it/otherwise get rid of it. Everyone who does NOT know about the new value I gave to that bill still thinks it's an ordinary 1 USD bill, not worth 100 USD and might carelessly spend it. Also if there were no way to know it's exactly THIS bill (no tracking/serial number) it also wouldn't work, as I  wouldn't be able to tell if I have to give out 100 USD back if someone hands me an unmarked bill.

Colored coins work similarly, you declare that some coins are "special" to you and represent shares or whatever. This special value or contract does not show up anywhere in a block chain (other than transactions with these coins) but they can be traced due to the public nature of the block chain. So if I then publish "I started giving some special value to THIS coin, then used it in this transaction etc." people can track which address holds these coins and see if they own any. Since the coins are potentially worth more than other coins of the same denomination (in the example: the 1 USD bill would be worth 100 USD minus the risk that I might not honor my contract) one could for example trade in the same chain for these special coins (in the example: someone buys the special 1 USD bill from someone else for 50 USD).

As these transactions take place in a block chain and not for example on a stock trading platform (e.g. A transfers to B 1 special coin and gets from B 1000 "normal" coins in return) you can cut out the middle man. Also you can create more arbitrary contracts. Issues mainly include mixing "normal" and "special" coins and making sure you don't accidentially spend your special coins like normal ones (in the example: buy an ice cream with the 1234567890 1 USD bill). This is why the ArmoryX software is being written, to take care of this and some other issues.

On one hand bitcoin's network structure + code is not the smartest one around and relies on flooding, so sending the same thing in different versions might cause even more problems.

On the other hand memory is even more expensive and probably limited amongst nodes than storage capacity for blocks. Bitcoin-qt already takes up ~half a GB of RAM on my machine, if it then has to store multiple versions of each transaction someone decides to publish it might get out of hand quickly. This stuff is not specified by the way and doesn't really influence the way blocks are built, so you can create your own client with a smarter netcode + multiple versions of the same transaction. Bitcoin-qt will probably not like your client, as it will be viewed as potential double-spender (or at least trying to cheat somehow), but as long as you manage to get these transactions to miners, I don't really see a problem that this cannot be done.

I would advise against it however, as there is little benefit to having multiple versions vs. updating one version, especially since in the end only one single version will be included anyways.

The incentive would be that even though it does not bring income, it reduces cost (in the sense of making the unspent outputs smaller).

A stronger counter argument could be that colored coins might get harder to track, on the other hand this stuff would work probably better on a merge-mined chain anyways...

One of the other questions (which is still under debate) is, if block space should be limited - if it is limited, "defragging" the unspent transactions is going to be costly and either has to be enforced by rules (e.g. "after latest 1 year with no transaction there HAS to be a refresh, to allow for a sliding blochchain") or it will happen out of necessity (having more unspent TX is more expensive than accepting regular transactions) of miners. If block size is unlimited (or practically unlimited), something like a shorter sliding block chain is easier to implement, as the next limiting factor then is probably rather the bandwidth (and refresh-transactions can be precalculated, so other nodes only need the TX-hash) between miners and network than block space.

The edge case would be to have these transaction in every block, meaning every block would contain a full set of all addresses with a balance - downloading all headers since genesis and 1 block is enough. However, one either needs then to precalculate a lot of refreshes (as a big part of blocks will be refreshes) and just receive the tiny delta of actual transactions each new block or a really fast internet connection.

The longer the chain becomes, the more additional "junk" is stored (transactions that could be pruned) but the smaller blocks can get due to fewer refreshes. The current chain is the other edge case - all blocks are needed to get the current set of unspent outputs and 0 refreshes are in the chain.

Having a flexible min. time would make it even harder to directly match lending offers and demands... I agree though that the "5 minute positions" are sometimes a pain in the rear end - especially since I'm not entirely sure if it does cause you to fall back with the rest of your offer in the lending queue.

Example (using VIR, the largest queue usually):

A, B and C lend 100 USD for 10 days each. A put the offer 2 days ago, B yesterday and C today. All have autolend active.

D takes 0.1 USD of A's position and pays it back 10 minutes later. A now has a 99.9 USD offer from 2 days ago and 0.1 USD today. I suspect that autolend in it's struggle to keep only 1 position open cancels the 99.9 position and lends out 100 USD again once the 0.1 USD are paid back. If it doesn't, D in his speedtrading "wisdom" would fragment the lending offers quite quickly - something that I don't see happening.

On the other hand, if the 0.1 USD get added to the old position again, it means B and C will never get a chance to lend even once, even if D borrows over 9000 USD over time, as A's old position always gets refilled.


Probably we just don't see these effects/problems a lot, because queues are cycled through so quickly over the day. Still a minimum interest (even if it is only 1 hour!) would be nice to have, especially if a tiny loan really causes a cycle (it seems to be somewhere in between - autolend opened a few new positions for me, on the other hand, they get partally filled with several different offers sometimes as well...) and pushes you to the end of the queue.

Hab das mal korrigiert...

Hashrate folgt Preis, nicht umgekehrt!

http://www.zurker.eu/update-1-115


Well, not facebook (yet?), but it's something!

Well, a "refresh" could be viewed as audited as well, since a block with an invaild refresh transaction would be considered invalid by other miners.

Alice can (after her few years in a coma) then just use the latest client and spend the 2015 refresh transaction just like any of her unspent outputs before. Anyone else is only allowed to create another refresh transaction to the same address - but she can sign a "real" transaction with her private key and use the refresh TX as input.

I only think there would be issues with more complex transactions (depending on several signatures, revocable or whatnot), if there are only N inputs to M outputs involved, I don't see why miners shouldn't be able to use N outputs as input to a special transaction that can only have inputs from the same address and can only output to this very same address. If the 2011 "refresh" wouldn't have been valid, it wouldn't have been included in the longest chain in the first place...?

Meldezettel vielleicht?

500kH/s bedeuten was genau an Hardwareaufwand? Laut https://github.com/litecoin-project/litecoin/wiki/Mining-hardware-comparison in etwa eine moderne GPU.

Milchmädchenrechnung:
Bei 750€ und recht teurem Strom um 25 cent pro kWh sind das 3 Megawattstunden an Stromkosten maximal in 8 Monaten --> ca. 12 Kilowattstunden pro Tag --> alles über ~500 Watt Leistung = Verlust, alles darunter = Gewinn.

In der Realität wird Strom wohl einiges billiger und andere Kosten einiges höher sein, trotzdem glaube ich, dass du mit diesem Angebot zu viel Gewinn machst und andere vermutlich das Gleiche um ~500€ ohne Verlust zu machen anbieten könnten. Mit meiner Hardware daheim könnte ich wohl in etwa 2€/Tag ohne Probleme schaffen - wieso kostet sowas bei dir über 3€?

When importing CSV files you can specify the decimal seperator. Also you could run a simple search + replace on the file. The "ugly hack" version would be to just divide or multiply by 1000

...which is around 60% atm by the way.

Do you have certain addresses in mind or what exactly is the problem?

My understanding is that you traded for some time on MtGox (EUR and USD) and are thinking now that you miss a certain (or uncertain) amount - you now want somebody to go through your trading history and tell you according to that data how much money you should have as evidence that you actually do have less than you should.

Have you tried just using Excel and a few conditions?

You'd see some old coins being moved then, most of the early mined 50 BTC outputs still lie dormant. They are either lost or stored long term. OP is worried about option 2

Ich hab eine Sapphire Vapor-X 5850 anzubieten, welchen Preis stellst du dir denn (excl. Versand) so in etwa vor?

P.S.: Du verwendest zu viele "z" an Stellen wo sie nicht hingehören...

What if I told you...

...water melons are actually orange on the outside and blue on the inside, but since everyone else calls these colours "green" and "red" you think they are green and red?

A transaction sharing 2 inputs is unfortunately only a strong hint, not a proof of ownership.
This might have been true a few years ago by the way, nowadays coins seem to be more dispersed.

So I want to send 0.1 BTC, but only have a 100 BTC unspent output... I have to pay 2% (2 BTC) just to move 0.1 BTC?!
Also 2% is not "VERY SMALL" at all, I can receive credit card payments for less fees.

https://bitcointalk.org/index.php?topic=152332.0 

Claiming something is potentially buggy + insecure is a valid concern, claiming that something is buggy and insecure leaves me wondering when you did a code and security audit...

Just as you would rightfully call anyone a liar who says "MPEX is unusable, the website is down" since you can do trades on IRC for example, also you could maybe understand a less tech savvy user who says "MPEX is unusable for me, I only know how to use the web interface and it's down atm". You seem to like generalizations and final/absolute statements, but this does not lead to useful discussions in my experience, so please refrain from that further on in this thread.


True, though a lot of "investments" so far on various platforms are passthroughs to other, more risky investments. Also at least this one has a sound, easy to understand business model that also pays in BTC, not USD converted eventually to BTC at some exchange rate determined by the operator. I don't see a way how the idea behind the investment could fail - the platform/execution itself can fail, yes, as I outlined in the OP already.


Yes, you don't need to pay 30 BTC (or a broker commission), have a huge opening balance (lolpirate) or get verified (though maybe this might change?) and compared to other "funds" I don't plan to diversify into other areas, so it's kinda specific. Maybe the entry into that market is too low to warrant a passthrough operation, but maybe there are other motives that might warrant a passthrough that I didn't think of, also a reason why I opened this thread.
So far I got: The investment itself is insecure, Bitfinex is insecure and passing through me is insecure - also doing the stuff on your own is too easy to warrant a PT...