I have always believed that Bitcoin (like other revolutionary tech internet, cellphones, electricity, analog telephone, social media, etc) is on a 10 to 20 year path towards mainstream adoption.  I said that two years ago and some people thought I was insane.  They thought (or claimed to think ) that Bitcoin would be bigger than PayPal and the exchange rate north of $100 by now.  

Bitcoin is very revolutionary in lots of different ways and that slows adoption.
a) It is decentralizing a concept most people assume "MUST" be centralized.  It takes a while before someone realizes that "money" can be decentralized.

b) It is complicated.  Without at least a basic understanding of cryptography (abstract) it is impossible to describe how Bitcoin works.  So either people need to believe in it based no pure faith or spend a couple hours (or weeks) educating themselves.  For most people it is easier to just take the faith route but that takes longer.  If Bitcoin is still around in 20 years and still acting a store of value most people will never understand exactly how it works they will just accept that it does.

c) It puts 100% of responsibility on the user.  Every other system gives users the ability to unload responsibility onto others.  This is likely why we saw so many things like mybitcoin and pirate nonsense.  People are use to the escape hatch and there isn't one in Bitcoin.  This means mainstream adoption will require both advanced hardware wallets (i.e. formatting hard drive and not losing $100,000 because you have no backup) and a change in culture (i.e. not giving $5M to a guy named "Pirate" who offers Ponzi like interest rates but promises without any proof that it isn't a ponzi) to protect users from themselves.

d) Bitcoin is so new it is hard to quantity.  For example FinCEN hasn't declared Bitcoin money or even made a definitive ruling that it is a "money substitute".  Obviously that is the very FIRST step.  You need to define something before you can start to regulate it.  You can't regulate the nebulous.  For example there are no laws about "meaness".  There may be laws about stalking or cyber bullying but not something as vague as "being mean".  FinCEN hasn't even gotten that far yet simply because Bitcoin is so radically different it doesn't fit into any of the nice boxes the government has already created.  When new products and services come out the government usually looks to figure out which box is the closest fit.  Is this a "security", a "commodity", "stored value" (now called prepaid access), a "foreign currency".  Bitcoin is similar to all of those but doesn't fit into any of those boxes.

Stephen is being nice.  Master Key = idiotic. 
A second password is no real security and offering it to users is simply going to lead to a false sense of security.

There is overhead to a loop (the loop logic itself).  In a FPGA that also involves the traces from the output back to the input for the next round of the loop.  Unrolling eliminates that.  Usually eliminating that overhead is worth more than the cost of unrolling.  There are exceptions but they are rare and far between.  The software used for planning FPGA layout tends to do better with unrolled constructs then rolled ones so that adds another source of improvement.  Keeping it rolled you likely will need some tedious hand placement.

Still it doesn't matter ASICs will be here soon and even if delayed 6 months it is still shorter than the break even time on a new FPGA.

The point is if you asked me to sign some random string I would tell you to pack sand.  Maybe that random string is the hash of a contract you later will claim I agreed to by signing (one which obligates me to pay you 100 BTC per year for example).  Or maybe the random string is you public key and you are using me signing it as proof in another scam with a third party.  See I am trusted, D&T is trusted and he signed my public key.  

Even if you are legit a random string could be used by third parties.  It doesn't really prove anything other than the signing party signed a random string.  As an example you there are two people A & B.  A claims to control address 123.... but doesn't really.  You ask A to sign a random string. A instead tricks Bob into signing the random string.  Maybe A sells Bob some gold coins and being naive A states that the random string is the order number.  A could even draw up a contract with the order # (your not so random string).   Bob signs the random string provided by A not knowing that it is A's intent to turn around and gives it to you as proof A controls address 123 which is a false claim as Bob actually does.

TL/DR:
Singing a random string is about as useful as a laywer asking you to sign a contract made out of random letters.  Would you physically sign a contract which is just pages and page and pages of seemingly random letters & numbers?  What is the lawyer says trust me it is random I just need you to sign something?  If you want the user to sign something then have the sign something meaningful.

What grue was indicating is that a better solution is to have the user sign something SPECIFIC that can't be used for any other purpose.  

Which is less likely to be abused ..

Signing this?

Or signing this?

BTW if you did sign the later guess what it is a SHA-256 hash of ... this ...

Nice site.  Looks like they don't support PM yet but plan to "soon".  Hell if they ended up supporting PM and BTC well that would be pure WIN.

https://fastcash4bitcoins.com  <-I'll leave this here.

Meh you are still stuck on this naive black or white thinking.  No VC woulnd't agree than any profit for any level of risk is better.  They wouldn't be VC for very long with that attitude.

Imagine two scenarios.  90% chance of 400% gain in a year vs 50% chance of 500% gain in a year.  Selling shovels (or mining rigs) is the the former, and trying to monopolize an open market is the later.   Nothing wrong with taking the "safe" easy bet and turning a million into four million and rolling that into new projects and ventures if/when the margins get squeezed.

On the topic of cartels they tend not to survive outside of governmental interference or natural monopolies neither of which exist in mining.  Any cartel would be quickly crushed by an outside selling millions upon millions of ASICs to the general public.  Natural monopolies aren't just monopolies they are ones which exploit the limitation or unequal distribution of the physical world.  For example OPEC is somewhat effective at controlling prices because oil distribution is "lumpy" and they can control enough to influence price, however a cartel of solar panel manufacturers would quickly be crushed by outsiders seeking to make a cut on the juicy cartel created profits.

Sure ... on enough tx volume. 

http://blockchain.info/charts/cost-per-transaction-percent

Costs (fees + subsidies) are currently ~1.7% of tx volume.  Granted 1.7% is pretty high but it was roughly 7% per year.  If tx volume keeps growing it is certainly possible for the network to be much much larger (i.e. hundreds of Exahashes/s) and costs as a % of annual tx volume to be a very low %.

OP has it wrong (and so do you) because you forget about the concept of risk and capital.

None of the ASIC designers had the capital to build ASICs without outside investment (either VC and/or pre-order funding).  Selling the miner is a much lower risk activity than mining yourself.   With VC they want a guaranteed risk profile before writing checks in the six figures and saying "we will build X miner devices at 200% gross markup and repay capital within 4 months is a a LOT  more attractive to a VC then well we will build lots of miners and we should break even within a couple months unless someone else does the same thing in which case it might be more like a year, unless someone releases a superior product to the general public in mass volume in which case we likely are going to lose everything".

Pre-orders are even better (from builder's POV) source of capital because the builder gets a cut of the profits and the buyer/miner takes all the risk.   I mean that scenario is like ... me taking your money playing Satoshi Dice and getting a % of all the wagers and you either win or lose.  Now granted if you win you may win much bigger than me but I would love a business model where I take all your money, and you take all the risk and we split the profits in some fashion.

Not only is the risk lower, the return on capital is also much higher.  Once the pre-orders have shipped BFL has already collected their capital back plus profits plus a share of the profits on the pre-orders capital (w/ the buyer taking all the risk).  The company can then do it again.  Same product cut the price 20%, then 40% then 50%, then 80%, then time to move to 32nm (double output per watt and per $), then cut the price 50%, then 70% .... etc.  Each time the timeframe on the return on capital is short.

Even if say BFL decided not to release any ASICs and had the millions in capital to build them all internally and was willing to take that risk what happens when a competitor releases ASICs to the general public.  
While "internal-BFL" may limit their production runs to maximize profit the competitor selling to the general public will face no such obstacle.  Their method to maximize profit would be to sell as many ASICs as possible and thus drive difficulty up many mangitudes.  This would cripple "internal-BFL" business plan.  

Unless one feels likely they can maintain a monopoly on ASIC technology there is a massive amount of risk trying to corner the market.  Maybe the profits are somewhat lower by selling the miners but it is a much more efficient use of capital AND the seller gets to unload all the risk on the miner.

Of course the miners don't even see it coming.  They are taking all the risk chasing this dream of insane profits and the only one who will be making those profits will be the ones handing out shovels.

Should be fixed now. 

Checking.

The arguments about government and state are just nonsense (not that I don't agree with them but it has no relevence on the topic at hand). 

Miners are paid for securing the network.  If the network isn't secure the coins have no value.

Encryption is only half the answer.  Sure encryption can ensure only the owner "spends (transfers) a coin however to have a functional transaction system you also need to ensure that a transaction isn't duplicated (aka "double spend").  In a traditional model that is accomplished using a central authority (i.e. eGold or Liberty Reserve).  In order to decentralize that process requires an alternative method to secure the network.   Bitcoin uses a proof of work.  PPC uses an different alternative caled proof of stake.  The initial distribution of currency is to miners but as miners sell, trade, and exchange the currency the second distribution to the general population occurs.

Your logic is like saying "what is the moral legitimacy of gold" based on some flawed premise that under a Gold standard the only mechanism on the entire planet to acquire and store wealth was mining gold.  Smart people, funny people, creative people, etc all were able to prosper under a gold standard without any knowledge or understanding on how to mine gold.  The initial distribution of gold was to gold miners but the second distribution to the general population enabled anyone to acquire gold.


Remember money isn't wealth.  Money is merely an accounting system.  Someone having a $100 bill isn't wealthy because of the $100 in abstract.  That person is "wealthy" because of what the $100 bill can purchase (i.e. goods and services).

I know of another *bitcoin.com

It is nbui32b3uirfhbdjkrhkjf3dkjfdhsjkfhajk389fhsdjkfghksl;hfklhgkjlfhjbitcoin.com how much do you think it is worth?

I can simulate FRC for you.  Give me x BTC and in a year (or whenever you want) I will give you some of them back (95% back for period of 1 year, prorated for shorter periods).
Hell I won't even keep the 5%, I will just send it to the miners as a tx fee.

Yeah I was thinking about scraping or using a low cost brokerage account and scrapping from that.  I was kinda hoping an API existed.  I will take a look at XE.COM.  $540 is sill kinda excessive but it is a lot cheaper than $4K.

One options is to ask for a refund address.  How this is done can vary depending on the circumstances.

For example is the user has an account the user could set a refund address (i.e. all refunds go HERE).  On a per tx basis is refunds are likely then a refund could be asked at the time of the transaction (before use is given the unique single use "deposit/payment" address).  For most merchants where refunds are unlikely (say less than 1% of all txs are refunded) the merchant could simply ask the user if/when the order is cancelled and needs to be refunded.

Tangible Cryptography uses the second option.  As part of the order process the user is required to provide a valid (checking using Bitcoin validaiton rules) refund address. 

I doubt one exists for BTC but using any one of the numerous BTC spot price APIs combine with a spot price API for silver it shoudn't be too difficult.

The problem is that finding spot prices of silver or other precious metals (in any currency) has been difficult.  I found one commercial webservice but at $4,000 for per minute quotes I think I will pass.

The larger point is that fees/profit isn't "bad".   Sure no reason to be excessively gouging your customers but anyone should turn a critical eye towards a service they operate completely free.
At best it tends to mean the operator is naive and likely dangerously under capitalized at worst the "free" is simply a hook to scam 100% of the deposits.

Even things like google aren't "free".  Google provides "free" searches because they make billions on ad revenue.   Google wouldn't index the entire internet at tremendous cost simply to provide searches for free with no revenue.

There is no such thing as the sender's address.  Transactions consist of multiple inputs and multiple outputs.

In Bitcoinj the transaction class contains an array of inputs.  You an iterate the inputs to get the adresses they were from.

Do understand this is bad practice.  If the user is sending from a web wallet, an exchange, a mining pool, a mixer service, or anywhere where they don't have control over the underlying wallet the addresses where the inputs originate from isn't guaranteed to represent the user. 

A much better solution is to simply give every user a unique address.  If user A is assigned bitcoin address 123456 then when you receive a tx sent to bitcoin address 123456 you simply credit account A.

Hmm... actually a broker will have reserves so they can buy immediately and repay themselves from client funds.  

A gold broker for example is someone (say APMEX) who is holding simultaneously a large amount of BOTH gold and cash.  If someone wants to buy they can accept cash, payout gold and then use the cash to rebuild their reserves.  If someone wants to sell they can accept gold, payout cash and then if their gold reserves get too large sell off some.  The utility (and thus reason) for the markup/markdown is the fact that they provide liquidity.  

A broker with no reserves isn't very useful.   Anyways best of luck just not seeing why someone would want to take up to 7 days to buy coins through a "broker" when they can buy coins directly in less than 7 days themselves (without markup).  Not sure you have thought this through.  If you don't trust your business enough to put your own funds in .... why should anyone else?  It also mean you don't have the reserves to cover any losses due to fraud (ACH/serve reversals) so honest customers funds are at risk too.