Which is no different than sending 100 million outputs to the same address.  The number of unique addresses is irrelivent.

Still even before IsDust this attack wouldn't work.  Low priority tx are not relayed unless they pay a fee and that fee would cost you 0.1 mBTC per KB.  So sure you can add 1 GB to the blockchain, no problem.  It just will cost you 100 BTC minimum in fees per GB plus the cost of the value of the tx themselves.  Also given that miners priority tx by fee amount and/or priority your low priority tx would simply gain the unused space in the blocks and thus it might take months or years to bloat the blockchain an extra GB (and this cost you a huge sum).

So IsDust is simply a secondary line of defense (it actually is intended to prevent another type of resource hog), the attack wasn't viable even before IsDust.

Bitcoin doesn't work on the concept of address balances.  An output needs to be stored until spent regardless of which address it is sent to.  So sending 1 million outputs to a single address takes as much space in the UXTO as sending 1 output to a million addresses.

To avoid spam attacks (the word fragmentation doesn't apply here), the network makes dust outputs smaller than 5430 satoshis non-standard.  Miners limit free space and min fee to be relayed for low priority txs is 0.1 mBTC per KB.  So there is no such attack, at least not a credible one which doesn't cost the attacker a small fortune.

Because it isn't wanted.  They were added as a compromise.  Without them altcoin talk would be spread across every forum and even into otherwise Bitcoin related threads.  It would create a never ending amount of work for mods.   This forum like many other forums has an off topic section as well.  Do you think it is because the owners are promoting off-topic topics?  Of course not, it is simply easier to have an off topic section and hopefully some users will use it and that self moderation reduces the workload.


See #1, same concept applied to foreign language boards.

It does however the proof of work is in the blockheader.  The block header is only 80 bytes every ~10 minutes or 4.2 MB per year.
https://en.bitcoin.it/wiki/Block_hashing_algorithm

Of course that assumes an average 10 minutes per block, if the network hashrate is growing it will be higher so you could add say 30% to assume average 30% network hashrate growth over time and it still is ~5MB per year or 1GB every two centuries.

The overwhelming majority of the blockchain size is from transactions not blockheaders.  That size will depend on tx volume which is hard to quantify.  Currently their is a 1MB limit per block and the post above shows the max size per year under that limit but eventually that limit will either be removed or raised.

Still even that doesn't tell the "whole story" because the full historical block chain is not needed for either mining or verifying transactions, only the pruned blockchain which contains a copy of all unspent outputs (UXTO) is needed for that.   Currently the UXTO is about 10% of the full blockchain and as a % that will decline overtime.  Estimating the size of the UXTO requiring guesstimating the likely number of future users and the average unspent outputs per user.  The second factor is going to vary wildly depending on what usage scenario of Bitcoin in the future.  If Bitcoin is used primarily as a store of wealth (think digital gold) then the UXTO can be relatively small compared to the user base, and if it is a common high velocity transaction medium then the UXTO may be very large compared to the base.

So making any guestimates for something more than a century away is pretty much a shot in the dark.  The good news is that Moore's law is alive and on any century long timeline Bitcoin simply can not grow faster than Moore's law.  That means that over the course of a lifetime the relative "cost" will go down.  As an example a 6TBs of storage today costs less than a 1GB hard drive I purchased in 1995.  That is a 6,000 increase in storage per dollar in less than 20 years.   I have no doubt that in 20 more years a multi PB drive will cost less than a TB one will today.

It is a little more complex than that using the low level API.

1) The API call you referenced includes block height & block hash.
2) You can then check if the block (by block hash) is in the MAIN CHAIN by checking the block.
3) Getting the most recent block would give you the # of confirmations (recent_block_height - tx_block_height = #confirmations).

Step #2 is important as the chain can fork and your tx can be in a block which is orphaned off the main chain.  In most cases an orphaned tx (a tx confirmed in an orphaned block) will also be confirmed in a block in the main chain but in the event of a double spend it won't.

Still honestly I would use bitcoind directly rather than add a trusted third party into a network which is trustless.  With bitcoind you can use waletnotify & blocknotify to create callback functions which will fire whenever there is a new tx or new block.

Of course it is, however the "plot" is very simple.

They designed a chip, a pretty good chip (at least on paper) but the chip wouldn't be ready for delivery until late Dec (possibly January if one was conservative and padded the timeline for possible delays).
Cointerra is charging $3 per GH/s for late Dec delivery, KNC is charging $20 per GH/s for Sept deliver.  $20 is more than $3 and it really is that simple.

HF has a product worth $3 per GH/s but they want more.  By lying (blatantly lying) to customers they got more, a lot more.  That is the "evil plot".  They simply lied to customers, from day 1 they never expected delivery before late Dec.  The one thing they didn't count on was real delays which may cause them to be unable to meet even their fake delivery date. 

Anyway you slice it the premium of prices above $3 per GH/s was simply stolen from customers under false pretenses.  That is an "evil plot".  Now it wouldn't make a good movie because unlike a bond villian it isn't particularly interesting or creative.  It is simply lying for financial gain or as the lawyery type would call it; fraud.

Condensation can only occur when the surface is cooler than the dewpoint which isn't going to happen inside a high temp miner chassis.

It is Christmas eve dude ...

still if it can't wait.   When nodes learn of a new block that orphans an existing block they add any tx from the orphaned block back to the memory pool when orphaning it.  Likewise nodes remove txs from the memory pool when they receive a block which extends the longest chain.   It is possible the tx is in both blocks and thus is added and removed from the memory pool as part of the reorg.

Orphaned tx can't be "lost" unless there is a double spend.

Life is easier when you start reading ...


Note the portion that last sentence which requires your agreement (with checkbox) in order to create the account.

Paper wallet?  using a random (aka 256 bit of entropy) private key rather than some almost guaranteed to be bruted forced brainwallet scheme?

What a great way to introduce someone to Bitcoin, give them a brainwallet, later when it is worth a small  fortune they go to check on it and find out someone robbed it years ago.

You would compute PubKeyB from PrivKeyB.  


Yes.  Posting technical answers after bedtime is not recommended.  I fixed it.


It depends on how severe the break in the hashing algorithm is.   Current to find a PubKeyHash preimage requires 2^160 inputs.  That is computationally infeasible.  If both RIPEMD-160 & SHA-256 were found to be significantly weakened through cryptanalysis it is possible (although unlikely in my opinion) that the average number of operations to produce a preimage would be reduced to a level that would make it computationally possible feasible to produce that number of keypairs.

That being said I honestly don't think this will be a useful attack vector, just pointing it out for he sake of completeness.  IMHO it is far more likely that ECDSA (or ECC in general or the specific curve used for Bitcoin) will be "broken" (and Bitcoin will migrate to new stronger address systems)  than either hashing algorithm (much less both of them).   Hashing algorithms have stood the test of time better than Public Key crypto and that advantage is compounded by the fact that Bitcoin uses two different algorithms.

Slight off topic but related: One thing I have always wondered is why Satoshi didn't "harden" mining the same way.  Something made Satoshi decide to "harden" the PubKeyHash by using two separate algorithms.  Why didn't he use the same hashing algorithm for both mining and pubkeys (i.e.  hash = RIPEMD-160(SHA-2(SHA-2(input)))  or hash = RIPEMD-160(SHA-2(input)) for both PubKeyHash and BlockHash )?  Whatever enhanced protected (however small or academic) it provides one it would provide the other.    It is likely academical because a break in SHA-256 might not even undermine mining but the code was there why not use it in both places?  We likely will never know.

You could "just" break RIPEMD-160 & SHA-256 OR ECDSA (limited to addresses where the PubKey is known).

Find a PubKeyB such that for an existing PubKey A they both produce the same PubKeyHash.

i.e.
PubKeyA =/= PubKey B
RIPEMD-160(SHA-256(PubKeyA)) == PubKeyHashA
RIPEMD-160(SHA-256(PubKeyB)) == PubKeyHashB
PubKeyHashA == PubKeyHashB

If PubKeyHashA == PubKeyHashB then the private key for either PubKeyA or PubKeyB can spend coins sent to Address A or B. In a "normal" Bitcoin tx (PayToPubKeyHash) you are not locking funds to a specific PubKey but locking them to a specific PubKeyHash.

 

Indeed it has been much longer and slower.  I can't comment much right but we will be launching soon.  Due to the holiday season it probably won't be until the first of the year but we may soft launch sooner.   As a long time supporter, if you would like more information just drop me an email.  I am going to lock this thread as the launch will be very public no chance of missing it.

No the first recorded trade was ~1,300 BTC = $1.

Except for the PHs and PHs of pre-orders which are going to be used no matter what.

If/when all the companies are selling from stock or have very short (say 30 day) pre-order windows the exchange rate might affect it but the "spike" likely drove in lots and lots of PH/s worth of pre-orders which will remain even when the price crashes back.

Bitcoin never going above $500 may have slowed pre-orders but the spike to $1200 and then falling back to $500 is just a lose lose for miners.

The network only works on satoshis (1E-8 or 0.00000001 BTC).  The block reward began as 5,000,000,000 satoshis (50 BTC) and it will be halved every 210,000 blocks (~4 years) until it reaches 1 satoshi and then go it goes to zero.

https://en.bitcoin.it/wiki/Controlled_supply

There is nothing special about a "whole Bitcoin" everything on the network is recorded in integers as satoshis.

You "could" if you made computers out of something other than matter and they occupied something other than space.

Exactly MtGox is simply in Japan because the founder is in Japan.  It probably was in MtGox financial best interest to relocate out of Japan years ago.

The JPY for example is one of the least traded currencies against the Bitcoin.

According to bitcointy (numbers rounded for brevity), the trade volume in the last six months:

This is something people don't really understand and it is one way that gold (or any commodity) naturally balances supply and demand.  In the "will bitcoin always be a bubble thread" it got me thinking that an altcoin could attempt to replicate this behavior by allowing miners to mine more coins at a higher cost to simulate the effect of marginal production.

To simplify what he is saying.  Gold doesn't have one production cost.  It varies considerably from one mine to another based on yield, complexity, labor costs, etc. 

As an example lets say There are mines with a production cost of $300 per ounce, some with $900 per ounce, some with $1200 per ounce and some which aren't being used with an estimated production of $2,000 an ounce.

Now the $300 mine never stops mining.  That mine runs 24/7/365 and no matter what the price of gold does they keep mining because it has remained above their cost of production for years.  Sometimes they make a larger profit sometimes they make a smaller profit but they always keep mining. 

The $900 mine has been in pretty solid production for some time now.  It is less profitable per ounce than the $300 mine and it is a little more risky (as prices falling below $900 is more likely than below $300) but it probably hasn't shut down in the past couple years.

The $1200 mine is hit or miss.   Sometimes it mines and sells off, sometimes it mines and holds onto the gold looking for better prices, and sometimes it just shuts down the mine because it doesn't make any sense to mine an ounce of gold for $1,200 and then sell it for $1,000.

The $2,000 mine has never operated other than some research drilling.  It still has some value on the books because someday the price of gold may rise above $2,000 or improved technology may drive the production cost down but it remains idle.

So how does this help to stabilize price?   As the price rises more mines go into production and as the price falls more mines go into an idle status.   Thus when prices are spiking increased production absorbs some of that increased demand and slows the rise in price, and when it slumps the shrinking supply offsets the shrinking demand and slows the price decline.

I haven't really thought it all the way through but I am thinking if there was some method (alt-coin Bitcoin will never be radically changed) that allowed a miner to mine extra coins at higher cost (electricity) then they would when the price spikes and that additional supply would act as an offset.