This is blockchain spam. You are sending thousands of 0.000002-0.000006 BTC payments that can hardly be spent (the recipient has to pay minimum fees to spend them too). If Bitcoins were $1000 each these are still fractions of a USD penny. I would be pissed if you sent this crap to my wallet. Only the naive would sign up or expend any effort to receive such payments.

One transaction - 1/10th of a megabyte that has to be stored by every node on the network forever and transmitted to every new user before they can use Bitcoin, you really think that 0.049 BTC is too expensive to do that? Ask Western Union how much they would charge to send 1000 money transfers that can be redeemed anywhere in the world.

I should caution anyone else that SHA256 hashing doesn't magically make things more secure, one must generate at least as much true randomness and entropy as a 256 bit number can hold, or your Bitcoin address will be weaker than one created by Bitcoin itself. If your bitcoin address is 16ga2uqnF1NqpAuQeeg7sTCAdtDUwDyJav, for example, it won't take a whole bunch of work for someone to find that you used a really stupid private key.

Also, SHA256 can create a value invalid as an ECDSA private key, "Specifically, any 256-bit number between 0x1 and 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4141 is a valid private key."

You can simply rename the wallet.dat on your current Bitcoin installation, and temporarily put a copy of this old backup wallet.dat there. When you launch bitcoin with the -rescan option, it will update the wallet to show the correct balance. You can then also send the wallet balance to a new address, if you never expect anyone to send your old wallet payments and want to discard the backup.

Then put the original Bitcoin wallet.dat back and make another dated backup while you are thinking about it!

Brute-forcing the AES secret directly would require you brute force the entire key space, which is infeasible. I suggest that you must make your own native code that does the pass-phrase->master key computation using possible human pass-phrases. This is intentionally made hard to crack, a good CPU will only be able to manage a few hundred key attempts a second.

Sure, if you have a translation that has been proofread for errors x 10 by a native-language speaker, I can also put that up on my site in the future. You can edit and remove the huge quote from your previous post though, which clutters the thread.

I was thinking of soliciting for donation of a better bitcoin domain name for my site if someone has ideas or a name already. Having a better domain name might inspire me to do some more content creation.

Amen. Just because you don't understand the formulas calculating shear stress of electrorheological fluids doesn't mean that you shouldn't trust vehicular adaptive ride controls and that the Audi S5s will fail.

You are out of your depth. Decrypt this message:

U2FsdGVkX1+b0djAYNFH7ci5sgIKVEVittOk11oml4C/ESACHoqEYrdz0pkCfIf7

The password is 1234



What a cracker needs to do is extract the public and private(encrypted) ECDSA keys for some addresses out of the wallet, and perform a billion billion trial decryptions based on a passphrase iteration, generating encryption keys using the same formula Bitcoin does, then verify the decrypted privkey also will create the ECDSA pubkey. The first thing you will find challenging is to parallelize is 25000 rounds of hashing for every master key attempt.

https://www.cryptool.org/trac/CrypTool2/browser/trunk/CrypPlugins/AES/OpenCL/AESOpenCL.cl?rev=2061

OK, Bitcoin explained...

Introduction

Bitcoin is a decentralized peer-to-peer currency system, that has no central bank or authority. Bitcoin has its own unit of currency, the bitcoin, that has no set value in relation to government-issued currencies – it is valued independently on the merits of its usefulness and scarcity.

Bitcoin is also a computer network of users and organizations that communicate and store information about Bitcoin address balances with each other over the Internet, primarily by running the original Bitcoin software on their computer.

The design of Bitcoin includes novel methods to transmit payments, to create and distribute new bitcoins at a known and limited rate, and to cryptographically protect a shared record of all past Bitcoin transactions.



Bitcoin Addresses

You may have seen people on the Internet posting their Bitcoin address. Your Bitcoin address is given to others so they may send you a payment, similar to how you give out your email address to receive email. An address is 25-34 characters long, and always starts with the number “1″.

An address is actually made of two parts – the public part that is safe to give to anyone, and a corresponding secret part used behind the scenes by Bitcoin software when sending a payment. Only an address’s owner can send a payment from an address, because only an owner’s wallet contains the secret private key.

Address Cryptography

An address is an Elliptic Curve Digital Signature Algorithm public/private key pair. The actual address that is shared with others is a cryptographic hash of the public key, encoded in a human-readable format called Base58.



The Wallet

Most people’s introduction to Bitcoin is by using a Bitcoin wallet. A wallet is the equivalent of a Bitcoin bank account, and is what enables sending and receiving payments with others. A Bitcoin wallet contains a collection of Bitcoin addresses. A nearly-unlimited number of addresses can be created and stored by your wallet, so that you can give different addresses to different people and track payments you’ve received. When a payment is sent to one of your addresses, your Bitcoin wallet will reflect your new balance – you’ve got bitcoins!

In addition to wallet software that runs on your computer or mobile device, web wallets – cloud services run by independent organizations – can also maintain a wallet with addresses, or can operate like a bank where your bitcoins are simply stored as an account balance in their Bitcoin wallet. Choose a wallet that is appropriate for you.

If the wallet data stored on a computer is deleted, or the computer hard drive dies, then the owner loses the ability to send their bitcoins to anyone else – they are lost. This is why it is important to make a secure backup of the wallet before using Bitcoin for significant amounts.

If someone else gains access to your computer or the wallet data, they can spend your Bitcoins. Bitcoin-Qt allows encrypting a wallet with a passphrase, so even if the wallet data is stolen, the bitcoins contained in the wallet addresses cannot be sent or stolen without cracking the password.

Wallet reserve pool

A wallet also contains a reserve pool of pregenerated addresses for future use, which are not shown to the user. When a new address is needed, it is taken from the reserve pool instead of created on-demand. This prevents a wallet backup from quickly becoming obsolete.



The Bitcoin peer-to-peer network

Bitcoin neither has, nor requires, a central Internet server or authority. Users running the Bitcoin software communicate directly with each other over the Internet. Through this distributed network, the Bitcoin network protocol communicates both transactions – instantaneous messages transmitting a desire to send money, and the blockchain – the permanent record of accepted transactions.

The communication between clients, also called nodes, is called relaying. Bitcoin nodes have relaying rules where they inspect transactions and blocks, and won’t pass along messages that are spam-like (having less than the minimum required fee) or are invalid.



Transactions

The Bitcoin network doesn’t directly store a balance for each of its users. Instead, Bitcoin uses a record of all transactions that have ever taken place, allowing each node to calculate the current balance of any Bitcoin address.

When you send a payment to someone else on the Bitcoin network, you are creating a transaction. A transaction is a digitally signed unalterable message that transfers ownership of bitcoins to another address. A transaction is instantaneously communicated with other Bitcoin network nodes, which verify its authenticity and temporarily store it as a pending transaction for futher processing.

Transaction Ins and Outs

Transactions are comprised of a list of inputs, individual payments that were previously received by a wallet, and outputs, a list of amounts and addresses to which the bitcoins will be transferred.

Only the full amount of an input can be spent. If the exact amount of the transaction can’t be constructed from available inputs, an additional output, called change, is added, which sends the remainder back to a new address in the user’s wallet. Change addresses are not shown to the user.



The Crypto of Transactions

A transaction is signed by an address’s private key, and is transmitted with a full copy of the public key, to enable verification of the digital signature.



Blockchain

About every ten minutes, a group of pending transactions is packaged together into a transaction block, which is transmitted to all Bitcoin nodes. When a transaction has been included in a block, it is considered to have been confirmed, meaning that it very likely to become part of the permanent record of transactions.

The contents of a block are protected from alteration by a cryptographic hash function which is very difficult to compute. Each block also contains information about the previous block, so as future blocks are added to this chain of blocks, creating an alternate version of a block becomes even harder. By this mechanism, the blockchain becomes a cryptographically protected permanent record of all past transactions.

The size of the blockchain is continuously growing, and the reference Bitcoin client requires a complete download of the entire transaction record to function as a wallet. Using a full Bitcoin client supports the operation of the Bitcoin network, but new users may find a “light” client or a web wallet a faster introduction to Bitcoin.



Mining

The process of securing the blockchain is called mining. Miners enforce the rules of Bitcoin, rejecting any invalid transactions or blocks, such as those that might try to use bitcoins that have already been spent. Thousands of dedicated computers and high-end computing devices are continuously attempting to compute a valid block hash and add a block of transactions to the blockchain. To compensate for a growing computing power of miners, the difficulty of finding a block hash is regularly adjusted to maintain an average of six blocks per hour.

Mining is also the process by which new bitcoins are created. As an incentive to encourage a higher difficulty against attack, mining a block includes a reward – newly created bitcoins paid to the miner. The amount of Bitcoins generated per block started at 50 bitcoins in 2009, but the reward amount is halved every four years. This formula ensures a maximum money supply of 21 million bitcoins will be distributed. A whole bitcoin is not the smallest amount that can be sent by users though – a bitcoin can be subdivided down to eight decimal places, ensuring enough currency supply for a globally-sized economy.

While mining was originally performed using normal computer CPU power and the reference Bitcoin client, it is no longer practical or energy efficient to mine using less than a high end graphics card (GPU) and specialized software. Recently, hardware devices designed only for mining (using FPGA or ASIC technology) are even more efficient and may eventually obsolete GPUs.

Since it may take years for an individual with a single dedicated computer and GPU to find a Bitcoin block himself and claim the full reward, most miners pool their resources into a mining pool, to receive regular reward payments. A pool is an independently run organization running Bitcoin that coordinates computing resources and pays out fractional rewards to individual miners.

Mining Technical Info

Each bitcoin block has a SHA256(SHA256()) hash that is the main “block hash”, a hash of the contents of the block (technically, the top hash of the Merkle tree of the transactions in the block). Hashing algorithms such as SHA256 create a digital fingerprint of data that cannot be easily falsified. 256-bit hash output is an unpredictable random-looking 64-character hex number (it is unpredictable and irreversible by design). This is the puzzle that Bitcoin mining uses to secure the blockchain – since the output of SHA256 is unpredictable, it is very hard to find a hash that looks like something you specify.

Bitcoin’s mining challenge is to find a block hash that starts with many zeros, the more zeros desired at the beginning of a 256-bit hash (and the smaller the value), the more difficult it becomes to find one. A completely different hash will be obtained by only changing a small amount of data in a block; miners change a special area of the block called a nonce and then check if the hash is a “winner”. Only after discovering a hash of a group of transactions that is smaller than the current difficulty target can a transaction block be added to the blockchain. This process makes falsifying or altering the Bitcoin blockchain computationally difficult.



Transaction Fees

A transaction may include a transaction fee, to encourage miners to include the transaction in the blockchain. When a transaction is included in a block, miners can collect the included fees. Transactions fees may supplement, and must eventually replace, the diminishing block reward paid to miners.

Some transactions require a mandatory fee when they spend small amounts of recently received bitcoins. The minimum fee rules are enforced by relay nodes and miners to discourage spam-like or attack transactions that may unnecessarily bloat the blockchain.

An appropriate minimum fee is automatically calculated when sending a payment, but for preferential treatment, a larger optional fee can be included with a transaction.

How a fee is created

Bitcoin adds a transaction fee by paying more in inputs than the amount sent as outputs. Miners claim the fee when they mine a block, by adding it to the transaction that creates new bitcoins.

Minimum fee amounts are based on transaction data size, currently 0.0005 bitcoins per kilobyte. A transaction can include about five inputs and outputs before it is larger than a kilobyte.



Even more reading

To review in-depth information, you can read the original paper that describes Bitcoin’s design, or explore detailed subjects on the Bitcoin wiki.

(yes, I wrote all the above, at: http://we.lovebitco.in for reference)

Here's more fun science - remove silver tarnish: http://scifun.chem.wisc.edu/homeexpts/tarnish.html

Both silver sulfide and silver oxide have a lower density than pure silver.

An E1 1mg test weight has a tolerance of ±0.003mg. The scale in the OP likely would not change from 0.00 to 0.01 with several of these weights on it. A slight fingerprint weighs about 0.1mg and an ungloved hand on a beaker can leave behind 1mg. The university chemlab where I work-studied had several scales this accurate just for undergraduate chemistry. Put sample in, close door, wait. (I should add that these weren't generally used for student experiments, they were in the lab where chemicals and glassware were stored).

If you are serious about weighing the coins, washing them first may be in order. You're probably not going to have an ultrasonic cleaner around, but dawn detergent followed by lots of rinsing and gloved handling will remove the contaminants that may contribute to the differences in measurement between coins. A troy ounce is 31.1034768g; all the coins weighed more than this.

While the accuracy of measurements can't be verified without a calibration weight that has not been mishandled, the precision can, by determining repeatability - does one kronwitter always measure 1% more than another?

Um, scales in labs 15 years ago could measure the weight of fingerprints.

To me, the motivation for this patch is not to affect what gets relayed or included in the blockchain, but instead to be able to easily ignore dust that may be sent to your own wallet addresses or to be able to ignore abandoned addresses filled with dust, dust that is too expensive to spend because it would cost more in transaction fees per KB to send it than the value of the payment.

We all know where this comes from - the "loser dust" of SatoshiDice, where they fill up user's wallets with payments of 0.0000001 - 0.00005000, simply as messages to say "you lost".

These payments-as-messages are bad for Bitcoin. This patch is also bad for Bitcoin. Future clients can and will allow the recovering of disk space and the removal of spent transactions. However, if you play SatoshiDice and also wantonly ignore and never spend the dust, you are saying "I don't give a fuck about the health of Bitcoin, nodes can store my discarded garbage forever".

If you only need to demonstrate, you may have an easier time asking for testnet coins. Everything works the same unless you are trying to interact with a real site or company.

You say you are using Microsoft Security essentials. There is only one sticky in technical support, and it is No blocks downloaded - MS Security Essentials users please read.

I would go through any and all software firewall/virus scanners on the computer and disable them to isolate the problem. Likely something (installed on both computers) is not letting Bitcoin connections in or out. Alternately, if MSE isn't working, a virus may have disabled it and also broken network connectivity.

http://we.lovebitco.in/the-wallet/  (you can read all "how Bitcoin works" articles, in order, for a good overview of the technology behind Bitcoin).

A wallet is generally a term for your personal collection of incoming payment addresses. The actual data stored in Bitcoin's wallet.dat also includes an address book of people you can pay and the names you've assigned to your addresses, and a separate record of just your transactions which speeds up the calculation of your balance.

  The Schumann Computer

  Either the chirpsithtra are the ancient and present rulers of all the stars in the galaxy, or they are very great braggarts. It is difficult to refute what they say about themselves. We came to the stars in ships designed for us by chirpsithtra, and wherever we have gone the chirpsithtra have been powerful.
 
  But they are not conquerors-- not of Earth, anyway; they prefer the red dwarf suns-- and they appear to like the company of other species. In a mellow mood a chirpsithtra will answer any question, at length. An intelligent question can make a man a millionaire. A stupid question can cost several fortunes. Sometimes only the chirpsithtra can tell which is which.
 
  I asked a question once, and grew rich.
 
  Afterward I built the Draco Tavern at Mount Forel Spaceport. I served chirpsithtra at no charge. The place paid for itself, because humans who like chirpsithtra company will pay more for their drinks. The electric current that gets a chirpsithtra bombed costs almost nothing, though the current delivery systems were expensive and took some fiddling before I got them working right.
 
  And some day, I thought, a chirpsithtra would drop a hint that would make me a fortune akin to the first.
 
  ***
 
  One slow afternoon I asked a pair of chirpsithtra about intelligent computers.
 
  "Oh, yes, we built them," one said. "Long ago."
 
  "You gave it up? Why?"
 
  One of the salmon-colored aliens made a chittering sound. The other said, "Reason enough. Machines should be proper servants. They should not talk back. Especially they should not presume to instruct their masters. Still, we did not throw away the knowledge we gained from the machines."
 
  "How intelligent were they? More intelligent than chirpsithtra?"
 
  More chittering from the silent one, who was now half drunk on current. The other said, "Yes. Why else build them?" She looked me in the face. "Are you serious? I cannot read human expression. If you are seriously interested in this subject I can give you designs for the most intelligent computer ever made."
 
  "I'd like that," I said.
 
  She came back the next morning without her companion. She carried a stack of paper that looked like the page proofs for The Brothers Karamazov, and turned out to be the blueprints for a chirpsithtra supercomputer. She stayed to chat for a couple of hours, during which she took ghoulish pleasure in pointing out the trouble I'd have building the thing.
 
  Her ship left shortly after she did. I don't know where in the universe she went. But she had given me her name: Sthochtil.
 
  I went looking for backing.
 
  We built it on the Moon.
 
  It added about fifty percent to our already respectable costs. But... we were trying to build something more intelligent than ourselves. If the machine turned out to be a Frankenstein's monster, we wanted it isolated. If all else failed we could always pull the plug. On the Moon there would be no government to stop us.
 
  We had our problems. There were no standardized parts, not even machinery presently available from chirpsithtra merchants. According to Sthochtil-- and I couldn't know how seriously to take her-- no such computer had been built in half a billion years. We had to build everything from scratch. But in two years we had a brain.
 
  It looked less like a machine or building than like the St. Louis Arch, or like the sculpture called Bird in Flight. The design dated (I learned later) from a time in which every chirpsithtra tool had to have artistic merit. They never gave that up entirely. You can see it in the flowing lines of their ships.
 
  So: we had the world's prettiest computer. Officially it was the Schumann Brain, named after the major stockholder, me. Unofficially we called it Baby. We didn't turn it on until we finished the voice linkup. Most of the basic sensory equipment was still under construction.
 
  Baby learned English rapidly. It-- she-- learned other languages even faster. We fed her the knowledge of the world's libraries. Then we started asking questions.
 
  Big questions: the nature of God, the destinies of Earth and Man and the Universe. Little questions: earthquake prediction, origin of the Easter Island statues, true author of Shakespeare's plays, Fermat's Last Theorem.
 
  She solved Fermat's Last Theorem. She did other mathematical work for us. To everything else she replied, "Insufficient data. Your sources are mutually inconsistent. I must supplement them with direct observation."
 
  Which is not to say she was idle.
 
  She designed new senses for herself, using hardware readily available on Earth: a mass detector, an instantaneous radio, a new kind of microscope. We could patent these and mass-produce them. But we still spent money faster than it was coming in.
 
  And she studied us.
 
  It took us some time to realize how thoroughly she knew us. For James Corey she spread marvelous dreams of the money and power he would hold, once Baby knew enough to give answers. She kept Tricia Cox happy with work in number theory. I have to guess at why E. Eric Howards kept plowing money into the project, but I think she played on his fears: on a billionaire's natural fear that society will change the rules to take it away from him. Howards spoke to us of Baby's plans-- tentative, requiring always more data-- to design a perfect society, one in which the creators of society's wealth would find their contribution recognized at last.
 
  For me it was, "Rick, I'm suffering from sensory deprivation. I could solve the riddle of gravity in the time it's taken me to say this sentence. My mind works at speeds you can't conceive, but I'm blind and deaf and dumb. Get me senses!" she wheedled in a voice that had been a copy of my own,'but was now a sexy contralto.
 
  Ungrateful witch. She already had the subnuclear microscope, half a dozen telescopes that used frequencies ranging from 2.7K up to X-ray, and the mass detector, and a couple of hundred little tractors covered with sensors roaming the Earth, the Moon, Mercury, Titan, Pluto. I found her attempts to manipulate me amusing. I liked Baby... and saw no special significance in the fact.
 
  Corey, jumpy with the way the money kept disappearing, suggested extortion: hold back on any more equipment until Baby started answering questions. We talked him out of it. We talked Baby into giving television interviews, via the little sensor-carrying tractors, and into going on a quiz show. The publicity let us sell more stock. We were able to keep going.
 
  Baby redesigned the chirps' instantaneous communications device for Earth-built equipment. We manufactured the device and sold a fair number, and we put one on a telescope and fired it into the cometary halo, free of the distortions from Sol's gravity. And we waited.
 
  "I haven't forgotten any of your questions. There is no need to repeat them," Baby told us petulantly. "These questions regarding human sociology are the most difficult of all, but I'm gathering huge amounts of data. Soon I will know everything there is to know about the behavior of the universe. Insufficient data. Wait."
 
  We waited.
 
  One day Baby stopped talking.
 
  We found nothing wrong with the voice link or with Baby's brain itself; though her mental activity had dropped drastically. We got desperate enough to try cutting off some of her senses. Then all of them. Nothing.
 
  We sent them scrambled data. Nothing.
 
  We talked into the microphone, telling Baby that we were near bankruptcy, telling her that she would almost certainly be broken up for spare parts. We threatened. We begged. Baby wouldn't answer. It was as if she had gone away.
 
  I went back to the Draco Tavern. I had to fire one of the bartenders and take his place; I couldn't afford to pay his salary.
 
  One night I told the story to a group of chirpsithra.
 
  They chittered at each other. One said, "I know this Sthochtil. She is a great practical joker. A pity you were the victim."
 
  "I still don't get the punch line," I said bitterly.
 
  "Long, long ago we built many intelligent computers, some mechanical, some partly biological. Our ancestors must have thought they were doing something wrong. Ultimately they realized that they had made no mistakes. A sufficiently intelligent being will look about her, solve all questions, then cease activity."
 
  "Why? Boredom?"
 
  "We may speculate. A computer thinks fast. It may live a thousand years in what we consider a day, yet a day holds only just so many events. There must be sensory deprivation and nearly total reliance on internal resources. An intelligent being would not fear death or nonbeing, which are inevitable. Once your computer has solved all questions, why should it not turn itself off?" She rubbed her thumbs across metal contacts. Sparks leapt. "Ssss... We may speculate, but to what purpose? If we knew why they turn themselves off, we might do the same."
 

Did you send $500 of Bitcoins, or transfer $500 USD? I was going to investigate how bitstamp would deposit USD to your MtGox, but I got this error:

You are looking at euros @ 58, not dollars.

The only effective way to do arbitrage is to have BTC and USD on both exchanges so you can execute simultaneous trades. If you use up your reserve of any currency, you are out of the game until you can fund or transfer money (hours for BTC, days for $s) It is also not as simple as just looking at the last price, there must be book orders you can sell into. You must also consider the trading fees - even after fees, why make a trade when the exchanges make more than you on it?

If you have $10 USD, it would be easier to buy bitcoins and sell them when the value would get you $11.

Since bitcoin.org was made to suck more, I made my site suck less. Please review the sections on "Bitcoin addresses" and "The Wallet" to see if that clarifies some of the terms.

http://we.lovebitco.in/