Where would I find that on bitcoin-qt?
The posts above provide some insight but I am wondering how you can be "absolutely sure" your copy of the blockchain is complete and yet not know what is the most current block you have downloaded.  I'm sure because there's no download bar and it doesn't say (out of sync). It says the most recent block is block 215520, as of this post, so it's definitely got the entire blockchain. Ok so does the transaction not show in the client at all? If so verify the address is in your list of transactions. You didn't by any chance send the coins to an address in your address book (other people's addresses). Assumming the tx is not listed in the client and it is a correct address you may need to restart the client using --rescan option (sorry there is no option in the GUI). Close the client, open command prompt/console and enter It will take a little longer than normal before the GUI appears (it is rescanning the blockchain to look for tx involving your keys). For windows you will need to ensure you are in the folder where bitcoin is installed. By default C:\Program Files (x86)\Bitcoin\
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Correct. I would add that the wallet encryption uses thousands of rounds of SHA-256 to convert the passphrase to the AES key.
So to OP when you say what encryption is used it is important to clarify what are you asking.
What algorithms does Bitcoin use to verify transactions? Transactions are signed by the private keys using ECDSA and verify by miners using the corresponding public keys to verify authenticity
vs
What algorithms does the client use to PROTECT the private keys? The client uses SHA-256 (for key generation) and AES_256 to encrypt/decrypt the private key portion of the wallet using a passphrase supplied by the user.
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Yeah I think you are going to find BTC to be more popular. If you want to make it a little more special you could opt for a physical bitcoin from (Cascius sp?). It seemed popular when we did that for our last promo.
Congrats on the first 10,000 BTC.
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Nonsense, many common payment mechanisms have horizons of _months_ before transactions become irreversible. Moreover, you can't simply reduce the time as though it were a free parameter. As the time between blocks falls below the time it takes nodes to globally communicate and validate new blocks the time until convergence tends to infinity. 10 minutes may have been more conservative than needed but it cannot be made arbitrarily low in a universe with a finite speed of light.
Whom want you to impress with such a beginner attitude stated in your last sentence? Almost all transaction in real life are much quicker than 10 minutes. Go to a train stop and image in 50 year use an electronic card when go into the train to pay. Or even today if you are in the shop and want to pay with your master-card. These TYPICAL transactions should be last say 10-15 sec AT VERY MOST. Therefore the time limit which is to be aimed at should be say 1 sec -- of course we have some decades time to reach it. If BTC-money payment only can go down to say 1 min, far more than 99 % of transactions in real-world usage will need another currency which is then of course of much higher importance, and then I see no sense to support BTC anymore myself -- it is (will stay) only a specialized currency in a small corner in the real world. Bitcoin transactions are processed in a few seconds just like credit cards. You will not the keyword above was irreversible. It takes up to 180 days before CC transactions are irreversible. On that scale 10-60 minutes doesn't seem excessively long. It is certainly possible to accept 0-confirm transactions. For physical world, and low value transactions that is likely all that is necessary. Also remember that the entire network needs to synchronize. That means propogation delays as well as verification delays need to be considered. Due to the nature of Bitcoin (verify -> relay -> verify -> relay -> verify -> relay ... etc) it may require multiple "hops" before all nodes have access to the same block. As gmaxwell pointed out 10 minutes is likely somewhat conservative one can certainly go lower but there is a cost and risk with going too low. Anything below 1 minute is likely not viable without excessively high rate of blockchain forks and orphaned blocks. Lets compare some transaction times for settlement and funds availability bitcoin 0confirm - ~ 1 sec bitcoin 1confirm - ~10 minutes (varies 6 to 30 min within 1 SD) bitcoin 6confirm - ~1 hour ACH (including "billpay") - 72 to 120 hours Bank Wire (domestic) - 4 to 12 hours Bank Wire (international) - 24 to 72 hours Western Union - 15 minutes (unless delayed due to fraud prevention) CC (inducing CC based systems) unconfirmed - ~1 to 15 sec CC (inducing CC based systems) confirmed - 2880 to 4320 hours Costs: Bitcoin < $0.01 per tx ACH ~$0.10 to $0.35 per tx Bank Wire ~$10.00 to $35 per tx Western Union ~7% to 10% of gross settlement Credit Cards ~2% to 3% of gross settlement Debit Cards ~1.5% of gross settlement Bitcoins unconfirmed and confirmed settlement times are as good or better than other payment networks and at a fraction of the cost. Still it seems you aren't really interested in learning or understanding so .... Yup bitcoin sucks and everything about it was chosen to annoy you. You likely should click logout and ignore it for another decade or two. |
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Forgive me if I'm wrong, but in a world where quantum computing becomes actually prevalent, as opposed to just plainly possible in a laboratory setting, there is nothing to stop Bitcoin from leveraging QC for it's encryption. This would kind of ruins the argument of ever more sophisticated QC cracking current cryptography; the new cryptographic possibilities that QC could achieve will eventually be available to the Bitcoin dev team, as well as the general public.
I'm not so sure about that. In Bitcoin you need a public key cryptosystem. In elliptic curve cryptography, the trick is that the direct problem (computing the public key or the signature) is easy if you know the private key. However, if you have the public key there is no known efficient method to deduce the private key (with a classical computer). If everyone had quantum computers, both problems would become easy. You cannot simply scale the numbers as you would with hashing. You need asymmetry. There are a few alternatives under study: http://en.wikipedia.org/wiki/Post-quantum_cryptographyThe important point is that, as opposed to symmetric systems, where you can just scale everything, you need some asymmetric problem. With quantum computers there are less available problems like that. Yes, I see what you mean. I read up on the maths behind cryptographic key pairs quite some time ago, and the (infinitely parallel?) nature of QC would blow that paradigm away. I guess that's what I'm driving at then: there must be some way of using quantum computers to create openly exchanged secrets that are inpenetrable to QC cracking methods. If not, then I guess all bets are truly off with just about every form of encryption that exists, even if there was some new discovery in cryptographic maths. Well, even that isn't entirely true with how Bitcoin uses public key encryption. Simply publishing a single bitcoin address doesn't actually publish the private key, it publishes a structured hash of the public key. The actual public key isn't published until the first time funds are spent from that address. If SHA-256 is subject to being brute forced into collisions by a quantum computer, a different hashing algo may not be, and that could be used instead. If you use a new address for each transaction, which is how bitcoin does it by default and really is a best practice, it would be very difficult for a quantum breaker to steal your coins. I apologize if I wasn't being clear with my post, I am aware that private keys cannot be computed from public keys (and the, er, *ahem* obvious security hole that would represent, lol). I imagine it would be possible to use the high level of parallel processing that a QC could be scaled up to to simply brute force private keys directly using the blockchain database. This would presumably take a QC with a high qubit count, but it's clearly the most common sense approach to hacking Bitcoin with quantum computing. It'd have to have a half decent rate of key discovery though, as the chances of finding a private key with alot of money in it's addresses could be pretty slim (this is an impression, I don't know any hard stats offhand, but I suspect the vast majority of keys have <10 BTC contained) I don't think you understand his point. Yes QC could (in theory) be used to determine the private key FROM the public key. However with Bitcoin the address isn't the public key it is a structured hash of the public key. The public key isn't known until the first time Bitcoins are spent from a given address. |
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Where would I find that on bitcoin-qt?
The posts above provide some insight but I am wondering how you can be "absolutely sure" your copy of the blockchain is complete and yet not know what is the most current block you have downloaded. |
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What is the current block according to your client?
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Oh good, my student loans might be inflated away
I am projecting that in all but the most devastating of collapse environments, Joe Sixpack will find that any documentable debts (to well connected parties) left over from the dollar days will be rolled into a similar debt valued whatever becomes the new legal tender, and normalized against some basket of tangibles. In other words, unless you are a multinational with derivatives losses and that sort of thing, you probably should not expect a free ride complements of a monetary re-set. As always, just my guess on how things would likely evolve. Under what basis. Imagining new contracts out of whole cloth? If so you got bigger problems then you think. I hope you have a personal army because the next step is some banker troops putting two bullets in your skull and taking all your PM. I mean we are talking about some future world scenario where magically no rule of law exists yet somehow bankers retain full control of their assets and the (para)military force to protect it. Forget bitcoins and gold stock up on water purificaiton equipment, rural land, good seeds, and enough manpower, firearms, and ammo to ensure nobody has the ability to take it. |
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Consumer surplus: median income - basic cost of living (adjusting both for family size).
If a new disease treatment is created that is far cheaper and more effective than previous treatments, GDP would fall but consumer surplus would rise (medical expenses portion of basic cost of living would decrease).
Why would GDP fall? Unless you think the consumer will not spend the money (i.e. my insulun use to cost $200 per month but now I have this pill for $20 per month which does the same thing so I guess I should burn this $180 left over)? |
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If you could get someone to accept a silver coin to buy $5 of groceries, how would they give you your change? Cut a silver coin into fractions? Weigh you out some scrap silver? Not likely. Gold and silver are assets/commodities, not really money. They're the best assets out there perhaps, but not money, not in a 21st century sense of the word.
You do realize the US operated on gold & silver coins for over a century. Later redeemable paper notes were used. Silver is "only" ~$30 per ounce. Coins can be relatively easily be made down to 0.1 ounces which would be ~$3 in purcashing power. If you need smaller denominations copper is great. At ~$0.30 per ounce it is good for sub $1 "change". Of course digital gold/silver is certainly possible. Trust is a concern which is why bitcoin will increasingly make inroads into the PM community. |
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Simple answer .... No,
Most long term "investment" schemes have turned out to be scams, poorly thought our business plans, or wannaba fund managers "investing" (i.e. destroying coins) in the prior two. Bitcoin is deflationary in nature so there is little need for interest to maintain purchasing power.
There are sites like btcjam which provide p2p lending but I don't believe they publish any stats showing ROI% (after default losses). Not sure what you mean you were in a BTC Pool which repaid with interest. I assume you don't mean mining. Most likely it was some form of a ponzi scheme. If you didn't lose money you simply stole from later investors victims who did. Count yourself lucky.
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1) Bitcoin will never be a national currency for the same reason that no country will return to the Gold standard. It is for a completely different reason
2) As the value of BTC rises it will be held by more and more people. By your logic nobody should buy/trade/acquire any more BTC. Half of them are already held by a tiny (globally speaking) number of people and thus outside would be better off not buying them and insider would be better off just selling them. Of course there will never be a scenario where Bitcoin goes to being held by thousands to being held by billions. The thousands will sell to tens of thousands who will sell to hundreds of thousands who will sell to millions. At the point where BTC had a large enough coinsupply to be useful for even a small nation the coins wouldn't be held by thousands they would be held by tens of millions.
3) Money isn't wealth, money is an accounting system. The rich hold a negligible rounding error of their total wealth in cash. The poor would benefit from a currency which isn't continually debased.
Of course I don't think Bitcoin will ever become a national currency however I don't think that provides any meaningful limit on adoption. Bitcoin could be used someday (in theory) by nation states as a strategic reserve (like Gold Bullion).
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You do know it is 5% per year right? So the 80M FRC the foundation has (or will have) will still be ~62M FRC in 5 years, 48M FRC in 10 years. Yes slowly all funds will be converted via demurage into miner rewards but this isn't something special with FRC it applies to all coins held by all wallets all the time.
You are forgetting the point of the foundation, to get rid of it's funds. The bylaws are being created right now, go help and suggest that all coins must be disbursed to end users within 5 years. Also, the math for 5%/year as a miner subsidy is dead easy at steady state. 100M coins at 5% demurrage (acutally 4.89%) is 4.89 million coins per year, or about 93 coins per block. Which requires absolute implicit trust = fail IMHO. If I trusted the FED to do the right thing I wouldn't need cryptocurrency. If I trusted PayPal, or eGold I wouldn't need Bitcoin. A decentralized "solution" which requires implicit trust in a central authority is of dubious value. You combine all the flaws of central authority with all the overhead of decentralizing the blockchain. Still that is a little off point I was just clarifying that while all the coins will go to miners "eventually" the half life on that eventually is about 13.5 years. |
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You do know it is 5% per year right? So the 80M FRC the foundation has (or will have) will still be ~62M FRC in 5 years, 48M FRC in 10 years. Yes slowly all funds will be converted via demurage into miner rewards but this isn't something special with the foundation, it applies to all FRC coins held by all wallets, all the time.
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Each new block (even if the only transaction it contains is the block reward) is another confirmation on top of all previous transactions that have already been added to blocks.
Hmm. 140 years from now when the block reward is 0 BTC, will miners still be required to add a 0 BTC block reward transaction to the blocks? Is that a requirement of the protocol?
Yes. For a block to be valid there must be exactly one coinbase tx per block. Not zero, and not two or more. The value of the coinbase must be equal to the block subsidy plus the sum of the tx fees (technically the sum of the outputs of all tx in the blocks minus the sum of the inputs of all tx in the block). So for a future 0 BTC subsidy block containing zero transactions the coinbase would need to be zero. Of course there is no economic value in hashing to find a zero BTC coinbase block so it would make sense for a miner to simply go idle until one (or more) unconfirmed transaction appear on the network. Still I doubt that will ever happen. If Bitcoin is still around 140 years from now it is highly probably the memory pool will never be empty. |
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Bah. eBay is too difficult! What if you just auction off sending an empty envelope to the address? With delivery confirmation, they would have to sign for it, confirming the received the envelope. That would be forced proof that a letter was received.
Ok once again.... Buyer signs for order, redeems the BTC and then charges the item back as "item not as described". They happily return the worthless piece of paper back to you. |
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Buyer signs for order, redeems the BTC and then charges the item back as "item not as described". They happily return the worthless piece of paper back to you.
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The network needs to be in consensus. You can't have a situation where for a given height there are two different blocks. If the attacker creates alternate blocks they would also be equally valid just different.
Example:
block 123
block 124A - block with tx where I pay you (includes hash of block123)
block 124B - block with tx where I double spend you (also includes hash of block 123)
now the network is split. part of the network believes 124A is the "real block124" and part of the network believes 124B is the "real block124". this can't remain forever otherwise the two portions of the network will fork off onto seperate incompatible sub networks.
How does bitcoin resolve this? miners will build upon the longest chain. So eventually block 125 will be solved. If 125 contains the blockhash for 124A then 124B gets orphaned and 124A becomes "the real 124". If 125 contains the blockhash for 124B then 124A gets orphaned.
Now if all that matters is a timestamp a block has no real value as unit of security/work. I wouldn't just create a new 124A I would create a new 124A, 125, 126, 127, 128 .... ten billion more block ....
tada the chain w/ my tx is in the longest so you lose. Of course you would be doing the same thing as would everyone on the network.
Bitcoin is based at is CORE around of concept of PROOF OF WORK. The fact that a tx is in a block (or buried x blocks deep in the blockchain) is PROOF of a certain amount of work. If the block is trivially produced then it is proof of NOTHING. There is no certainty in transactions, no "guarantee" the transactions can't be reversed (easily).
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An attacker could trivially change the timestamp. It is just a number.
Say I pay you and it gets included in a block with a timestamp of X. What would prevent me from just making another block with an earlier timestamp where I didn't pay you. Absolutely nothing. Of course anyone could do that to any transaction and the coins would have no value at all. The proof of work makes it have a real economic cost to attempt such revising of history and unless you have more than all the "good guys" combined the odds are stacked against you being successful.
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Three reasons
1) miners don't have to include your tx in the next block. if you have no fee and the block is particularly large they may just leave it for some future block. if your tx is particularly "spammy" (large numbers of low value inputs, bloating the size) it is more likely it will just be ignored.
2) blocks aren't once every 10 minutes. The process is random (it has to be in a decentralized network). On average the time between blocks is 10 minutes but individual times per block could be 1 minute or could be 120 minutes.
3) the network retargets only once ever 2014 blocks. if network hashrate is declined since the last retarget the difficulty will be "too high" until the retarget and thus the average time between blocks will be slightly higher than 10 minutes.
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