> I could see a market for some sort of mobile charger mounted in a truck
That would be a large alternator connected to the truck's engine. They already have those, but for charging an electric car, you might want to swap out the regular alternator for an extra-powerful one.
The only legitimate appeal of, or need for, an alternative currency is that it's more stable than government currencies
This is incorrect. If you are a merchant, avoiding 5% of your total cost on a transaction by using an alternate currency is plenty of reason. That savings comes from reduced fraud and chargebacks, and lower fees relative to bank cards and PayPal. If you are an individual trying to send money long distance, the lower fees relative to Western Union, PayPal, or bank wires is very attractive. The ability to shop online if you don't have a credit card is also attractive.
To be sure, fluctuating value relative to other currencies is a detriment, but payment processors like Bitpay take out the risk for merchants, and websites can and do price in bitcoins in real time against the exchange rate. The need for those sorts of work-arounds will go down as bitcoin gets wider use. The more people that use it, the lower the price fluctuations, becase any given person buying or selling will have less effect on the market.
Think about it. The creator of bitcoin had a deep understanding of networks and cryptography. The block chain is a *public* history of every bitcoin transaction worldwide. Perfect transparency for whoever wants to monitor it. A team at the NSA is as good an explanation for who "Satoshi Nakamoto" was as anything else.
Miners are looking for the lottery number (nonce) such that it plus a set of new bitcoin transactions and the hash of the previous block generates a new hash with a lot of leading zeros. The exact number the new hash has to be below is set by the total hashing power of the network. Thus the difficulty of the lottery is adjusted so that a new block is found every 10 minutes. If you win the lottery, you get to include 25 newly created bitcoins addressed to your own account, plus any transaction fees. At the moment this is worth $3500 or so per block.
Any hash calculation which does not result in a new block gets nothing. It is a losing lottery ticket, and the unwilling botnet victim just wasted electricity. The botnet operator only makes anything if they discover a winning number and publishes the new block. The combined hashing power of the network is 5 times the 120 Petaflops of the Top500 list of supercomputers *combined*. So unless the botnet operator has an asounding number of bots, odds are he hasn't earned anything.
The nature of the bitcoin network is there is no way to tell a botnet from a fast but legitimate mining rig *within the network*. If you submit a correctly formed block, it gets accepted by the other nodes in the network and added to the permanent transaction history (block chain). You might be able to match IP address of the botnet controller to the bitcoin node address, but I assume anyone smart enough to run a botnet knows how to use proxies to mask their location.
By design, transactions are irreversible, and accounts cannot be impounded by anyone, because accounts exist in a distributed form on multiple copies of the block chain (every node has a full copy). As a user, you have a private key to sign new transactions, which proves you own the account. The most you could do is seize the private key if you can find the perpetrator, and then take their balance from them. If they had already spent their balance on sex, drugs, and rock-n-roll, though, the money is gone, because *transactions are irreversible*.
Although this allows evil botnet operators to function, the tamper-resistance of bitcoin also prevents governments from seizing accounts or taxing them without first finding the owners. This is not easy, because although the transaction history is public, owner names are not part of the history, just account numbers and how many bitcoins to transfer.
Make an encrypted archive with strong encryption that contains you wallet.dat file (private keys). Store that archive in several places, like email it to yourself, dropbox, skydrive, bank safety deposit box
Note: your account balance is still on the block chain record of transactions. So the bitcoins are still there, you just don't have authorization to spend them if you lose your keys.
They don't need to brute force your encryption. First they gather lots and lots of databases (credit cards, google searches, facebook, etc.) Then they trawl the data for interesting correlations: Ah, so person X uses TOR visits Mexico regularly spends a lot more on their credit cards than their job can support. How interesting! They can then single out these people for more attention. Use of encryption is just one of the factors that goes into sifting out the interesting people to watch.
Another example: buys fertilizer and has a farm that is in the family for decades ---> not interesting. Buys fertilizer and lives in an apartment --> very interesting.
You can set up hundreds of factors like that, and none of them involve breaking codes.
> Seriously, wouldn't sending a handful of robotic spacecraft to characterize larger asteroids be much more worthwhile?
If you design the asteroid tug right, after it returns with the first one, you can refuel it and sent it out to get another. If you use plasma (VASIMR) type thrusters, you can use oxygen as propellant. You need 2-3% of the asteroid mass as fuel, and asteroids are typically 40% Oxygen. Therefore once you get an extraction plant working, the mining is self-sustaining on fuel. You just need to replace solar arrays and thrusters when they wear out.
At 500 tons every couple of years round trip, a self-fueling tug can jumpstart serious space construction.
> L1 is great as a pass-through point for a lunar elevator,
Rotovator/Skyhook type rotating elevators are demonstrably better in mass ratio, transit time, and meteor exposure than a stationary elevator.
Assume you want to take off and land from the Moon, and your rotating elevator is designed for a comfortable 1 gravity at the tips. Lunar orbit velocity @ 280 km altitude is 1560 m/s. To have an equal rotation tip velocity @ 1 g you need a 248 km radius. Thus the tip becomes motionless over the Lunar surface at about 30 km altitude (we want some clearance to avoid mountains and for orbit shifts). The rotation period is 1000 seconds. If you wait half a rotation and let go, you are moving at twice orbit velocity, because the velocity of tip + orbit motion of the center of the structure now add instead of cancel. This is more than enough to escape the Moon. By climbing some part of the 248 km radius and timing when you let go, you can inject to a wide range of orbits. Compare this to climbing a 60,000 km stationary elevator to Earth-Moon L1. It takes longer, and is more limited in destinations. Not to mention 120 times less exposure to damage from meteoroids.
As far as materials required, the acceleration varies linearly from center to tip, so it is equivalent to 124 km stress at 1 gravity. Carbon fiber has a scale length of 360 km ( http://upload.wikimedia.org/wikipedia/commons/d/d4/Materials_Scale_Height_and_Tip_Velocity.PNG ). Allowing a 2.8 reduction of the breaking strength for factor of safety and structural overhead, we get 128 km design scale. Rotating structures need to taper by a factor of e per design scale, so this Rotovator would taper by a factor of 2.8 from center to tip. This is quite reasonable as a design.
You appear to have missed "hydrates" - minerals with chemically bound water. See table 5 (p44) at http://www.higp.hawaii.edu/~escott/Scott%20Krot%20TOG2007.pdf Many of the minerals listed contain bound water, or OH components which can be driven off by heating.
Actually, internally the bitcoin software works in Satoshi. The maximum number of Satoshi (2.1 quadrillion) can be represented as a 51 bit integer, therefore it fits in the mantissa of an IEEE 754 double precision float.
Bittorrent doesn't affect the root of their power - their ability to create money out of thin air, and to tax money already in circulation. They would work much harder to stop something that threatens their very existence (without a paycheck, how many people will continue working for the government?).
In the pool that I use for mining, about 1% of the shares I mine are "stale", meaning someone else in another pool solved the block during the 4 seconds between when I got the share of work to process, and when I returned it. It's just a cost of business that I don't get any part of the block reward for a stale share, because nobody in the pool as a whole doesn't get it. Ties are treated the same way, if the pool doesn't get the reward, oh well, just start on the next one.
There is a hard limit of 1 MB per block, and therefore about 4000 transactions/10 minutes, and ~144 MB/day. That is because each transaction requires ~250 bytes of data. The block chain therefore has a linear growth limit. I don't know about you, but the last hard drive I bought could fit 38 years worth of transactions on it and cost $70.
What will happen is that the mining rewards for blocks will decrease every 4 years, making transaction fees relatively more important for miners. Therefore they have an incentive to process transactions with higher fees. In turn, this will force the creation of new transaction pools using the same block chain technology. The pools will condense multiple transactions from individuals into single larger ones on the main block chain, and deliver the details as side transmissions to each other directly.
This is analogous to how banks use the Federal Reserve to clear transaction balances among each other on a periodic basis (daily last time I looked), while doing the detailed accounts internally. Thus the block chain will end up being used directly for large transactions and pools, and stay a manageable size.
As an individual, you would keep your local pool block chain, and the main central one, both of which grow linearly, while the total bitcoin network can expand by the number of local pools splitting the daily transaction limit of 576,000 on the central block chain.
It is not like you can take a bitcoin rig and do anything worthwhile with it.
I'm typing this slashdot comment right now with it. My graphics card is mining in the background, in parallel with providing the display for both monitors. The displays only slow it down about 2%, and playing video on the larger monitor eats about 1/6 of the mining speed. If I was playing a heavy duty video game I would have to shut down the mining program, but most other PC tasks can work just fine in parallel.
If you are going to include distributed systems, then google's million or so servers probably takes the prize for most powerful. We don''t know for sure, since they don't publish details about their data centers.
Every central bank has a monopoly on issuing its national currency, so it is all monopoly money. Can you point to any nation with a competitive market for currency?
In fact, Bitcoin is the opposite of monopoly money, as it does have competitors, and is open-source itself, so other people can set up competing versions by modifying the source code. This has already been done.
Slashdot Mirror
> I could see a market for some sort of mobile charger mounted in a truck
That would be a large alternator connected to the truck's engine. They already have those, but for charging an electric car, you might want to swap out the regular alternator for an extra-powerful one.
They may have sold 100M licenses to manufacturers, but adoption is still under 4%: http://www.netmarketshare.com/operating-system-market-share.aspx?qprid=10&qpcustomd=0
And with Electronic Arts, I guess they found one.
The only legitimate appeal of, or need for, an alternative currency is that it's more stable than government currencies
This is incorrect. If you are a merchant, avoiding 5% of your total cost on a transaction by using an alternate currency is plenty of reason. That savings comes from reduced fraud and chargebacks, and lower fees relative to bank cards and PayPal. If you are an individual trying to send money long distance, the lower fees relative to Western Union, PayPal, or bank wires is very attractive. The ability to shop online if you don't have a credit card is also attractive.
To be sure, fluctuating value relative to other currencies is a detriment, but payment processors like Bitpay take out the risk for merchants, and websites can and do price in bitcoins in real time against the exchange rate. The need for those sorts of work-arounds will go down as bitcoin gets wider use. The more people that use it, the lower the price fluctuations, becase any given person buying or selling will have less effect on the market.
Why would they want to take it over if they created it in the first place?
http://i.qkme.me/3taipf.jpg
Think about it. The creator of bitcoin had a deep understanding of networks and cryptography. The block chain is a *public* history of every bitcoin transaction worldwide. Perfect transparency for whoever wants to monitor it. A team at the NSA is as good an explanation for who "Satoshi Nakamoto" was as anything else.
> Can I buy stuff from Amazon or some other online shop with Bitcoins?
Yes: https://bitspend.net/
https://www.bitcoinstore.com/
And in a wonderful example of self-reference, this Slashdot article is referenced in the Wikipedia article.
Miners are looking for the lottery number (nonce) such that it plus a set of new bitcoin transactions and the hash of the previous block generates a new hash with a lot of leading zeros. The exact number the new hash has to be below is set by the total hashing power of the network. Thus the difficulty of the lottery is adjusted so that a new block is found every 10 minutes. If you win the lottery, you get to include 25 newly created bitcoins addressed to your own account, plus any transaction fees. At the moment this is worth $3500 or so per block.
Any hash calculation which does not result in a new block gets nothing. It is a losing lottery ticket, and the unwilling botnet victim just wasted electricity. The botnet operator only makes anything if they discover a winning number and publishes the new block. The combined hashing power of the network is 5 times the 120 Petaflops of the Top500 list of supercomputers *combined*. So unless the botnet operator has an asounding number of bots, odds are he hasn't earned anything.
The nature of the bitcoin network is there is no way to tell a botnet from a fast but legitimate mining rig *within the network*. If you submit a correctly formed block, it gets accepted by the other nodes in the network and added to the permanent transaction history (block chain). You might be able to match IP address of the botnet controller to the bitcoin node address, but I assume anyone smart enough to run a botnet knows how to use proxies to mask their location.
By design, transactions are irreversible, and accounts cannot be impounded by anyone, because accounts exist in a distributed form on multiple copies of the block chain (every node has a full copy). As a user, you have a private key to sign new transactions, which proves you own the account. The most you could do is seize the private key if you can find the perpetrator, and then take their balance from them. If they had already spent their balance on sex, drugs, and rock-n-roll, though, the money is gone, because *transactions are irreversible*.
Although this allows evil botnet operators to function, the tamper-resistance of bitcoin also prevents governments from seizing accounts or taxing them without first finding the owners. This is not easy, because although the transaction history is public, owner names are not part of the history, just account numbers and how many bitcoins to transfer.
Make an encrypted archive with strong encryption that contains you wallet.dat file (private keys). Store that archive in several places, like email it to yourself, dropbox, skydrive, bank safety deposit box
Note: your account balance is still on the block chain record of transactions. So the bitcoins are still there, you just don't have authorization to spend them if you lose your keys.
They don't need to brute force your encryption. First they gather lots and lots of databases (credit cards, google searches, facebook, etc.) Then they trawl the data for interesting correlations: Ah, so person X uses TOR visits Mexico regularly spends a lot more on their credit cards than their job can support. How interesting! They can then single out these people for more attention. Use of encryption is just one of the factors that goes into sifting out the interesting people to watch.
Another example: buys fertilizer and has a farm that is in the family for decades ---> not interesting. Buys fertilizer and lives in an apartment --> very interesting.
You can set up hundreds of factors like that, and none of them involve breaking codes.
> Seriously, wouldn't sending a handful of robotic spacecraft to characterize larger asteroids be much more worthwhile?
If you design the asteroid tug right, after it returns with the first one, you can refuel it and sent it out to get another. If you use plasma (VASIMR) type thrusters, you can use oxygen as propellant. You need 2-3% of the asteroid mass as fuel, and asteroids are typically 40% Oxygen. Therefore once you get an extraction plant working, the mining is self-sustaining on fuel. You just need to replace solar arrays and thrusters when they wear out.
At 500 tons every couple of years round trip, a self-fueling tug can jumpstart serious space construction.
> L1 is great as a pass-through point for a lunar elevator,
Rotovator/Skyhook type rotating elevators are demonstrably better in mass ratio, transit time, and meteor exposure than a stationary elevator.
Assume you want to take off and land from the Moon, and your rotating elevator is designed for a comfortable 1 gravity at the tips. Lunar orbit velocity @ 280 km altitude is 1560 m/s. To have an equal rotation tip velocity @ 1 g you need a 248 km radius. Thus the tip becomes motionless over the Lunar surface at about 30 km altitude (we want some clearance to avoid mountains and for orbit shifts). The rotation period is 1000 seconds. If you wait half a rotation and let go, you are moving at twice orbit velocity, because the velocity of tip + orbit motion of the center of the structure now add instead of cancel. This is more than enough to escape the Moon. By climbing some part of the 248 km radius and timing when you let go, you can inject to a wide range of orbits. Compare this to climbing a 60,000 km stationary elevator to Earth-Moon L1. It takes longer, and is more limited in destinations. Not to mention 120 times less exposure to damage from meteoroids.
As far as materials required, the acceleration varies linearly from center to tip, so it is equivalent to 124 km stress at 1 gravity. Carbon fiber has a scale length of 360 km ( http://upload.wikimedia.org/wikipedia/commons/d/d4/Materials_Scale_Height_and_Tip_Velocity.PNG ). Allowing a 2.8 reduction of the breaking strength for factor of safety and structural overhead, we get 128 km design scale. Rotating structures need to taper by a factor of e per design scale, so this Rotovator would taper by a factor of 2.8 from center to tip. This is quite reasonable as a design.
You appear to have missed "hydrates" - minerals with chemically bound water. See table 5 (p44) at http://www.higp.hawaii.edu/~escott/Scott%20Krot%20TOG2007.pdf Many of the minerals listed contain bound water, or OH components which can be driven off by heating.
Actually, internally the bitcoin software works in Satoshi. The maximum number of Satoshi (2.1 quadrillion) can be represented as a 51 bit integer, therefore it fits in the mantissa of an IEEE 754 double precision float.
You do realize that every crank has proclaimed that his or her particular brand of crankery is a revolution, right?
Well, yes. You turn the crank once and it makes one revolution. Turn it again, two revolutions, etc.
Bittorrent doesn't affect the root of their power - their ability to create money out of thin air, and to tax money already in circulation. They would work much harder to stop something that threatens their very existence (without a paycheck, how many people will continue working for the government?).
There's a quickmeme for that:
http://i.qkme.me/3taipf.jpg
In the pool that I use for mining, about 1% of the shares I mine are "stale", meaning someone else in another pool solved the block during the 4 seconds between when I got the share of work to process, and when I returned it. It's just a cost of business that I don't get any part of the block reward for a stale share, because nobody in the pool as a whole doesn't get it. Ties are treated the same way, if the pool doesn't get the reward, oh well, just start on the next one.
When millions of users are making transactions every day the miners will be unable to keep up with the transactions
Not to mention that the entire blockchain grows exponentially longer with every transaction and is already at 6GB. A few more years and it will be hundreds of terrabytes.
There is a hard limit of 1 MB per block, and therefore about 4000 transactions/10 minutes, and ~144 MB/day. That is because each transaction requires ~250 bytes of data. The block chain therefore has a linear growth limit. I don't know about you, but the last hard drive I bought could fit 38 years worth of transactions on it and cost $70.
What will happen is that the mining rewards for blocks will decrease every 4 years, making transaction fees relatively more important for miners. Therefore they have an incentive to process transactions with higher fees. In turn, this will force the creation of new transaction pools using the same block chain technology. The pools will condense multiple transactions from individuals into single larger ones on the main block chain, and deliver the details as side transmissions to each other directly.
This is analogous to how banks use the Federal Reserve to clear transaction balances among each other on a periodic basis (daily last time I looked), while doing the detailed accounts internally. Thus the block chain will end up being used directly for large transactions and pools, and stay a manageable size.
As an individual, you would keep your local pool block chain, and the main central one, both of which grow linearly, while the total bitcoin network can expand by the number of local pools splitting the daily transaction limit of 576,000 on the central block chain.
It is not like you can take a bitcoin rig and do anything worthwhile with it.
I'm typing this slashdot comment right now with it. My graphics card is mining in the background, in parallel with providing the display for both monitors. The displays only slow it down about 2%, and playing video on the larger monitor eats about 1/6 of the mining speed. If I was playing a heavy duty video game I would have to shut down the mining program, but most other PC tasks can work just fine in parallel.
If you are going to include distributed systems, then google's million or so servers probably takes the prize for most powerful. We don''t know for sure, since they don't publish details about their data centers.
Every central bank has a monopoly on issuing its national currency, so it is all monopoly money. Can you point to any nation with a competitive market for currency?
In fact, Bitcoin is the opposite of monopoly money, as it does have competitors, and is open-source itself, so other people can set up competing versions by modifying the source code. This has already been done.
You could look here:
https://en.bitcoin.it/wiki/Trade
>. I don't know of any bank that will exchange bitcoins.
Silicon Valley Bank: http://marblesecurity.com/bitcoin-gains-more-legitimacy-with-silicon-vslley-bank-support/
> I've always wanted the ability to painlessly send someone money, directly,
Behold: http://bitcoin.org/en/
It's not everywhere yet, but it will be soon.