Nope.  Anyone can send coins to any address, even if it has never been seen on the network.  The address includes a checksum to prevent typos, but other than that there are no restrictions and no verification that anyone actually has the corresponding private key.


Yes, but the probability is absurdly low.  If every computer on Earth was dedicated to generating keys it would still be extremely unlikely to have any collisions before the sun explodes and destroys everything.


In that case (which will never happen), either person would be able to spend any coins sent to that address.


I suggest you use a paper wallet generator.  It gives you much less data to store and the secret key import format will be much more forward-compatible than relying on a future version of the client to open an old wallet.dat.

https://en.bitcoin.it/wiki/Paper_wallet
https://www.bitaddress.org/

No problem, glad to help!

I don't see "accumulative total".  Take a look here: http://blockchain.info/address/1MCARALEqNoLfQT1XdoxtTREk8L6kvHYm ... There's "Total Received" (which means everything, ever) and "Final Balance" (which means just the coins that remain).  Similar stuff here: http://blockchain.info/address-balance-sheet?address=1MCARALEqNoLfQT1XdoxtTREk8L6kvHYm&

The IPs are just the first nodes that blockchain.info saw transactions come from.  It doesn't mean you're on those IPs, just that you connected to the p2p network through them or near them.

The address shows 25.60112 BTC in, 25.60112 BTC out, zero current balance.  BlockExplorer agrees.  How much did you expect to see there?

Do you mind posting the address so we can have a look?

Mainstream media is not your friend.  I'm speaking from experience here.

I am not eager to be portrayed as a socially-inept criminal who gets off because he's technically not doing anything illegal but dang it there ought to be a law to put an end to those black market enabling, authority-undermining bitcoiners.

I do it like this:



It's useful for analyzing bot behavior, and it's handy when explaining market behavior to people.  It's a little more relevant in Bitcoin than typical markets: here we have a few people (I've seen 2 or 3 distinct patterns) who have enough capital to significantly shove the market around (The Manipulator).  You can spot them this way.

Once you've figured those things out, stick to the price charts for your actual trading.  Anyone can put bogus signals in the depth to exploit bots or get the paranoids in a tizzy, but long term what matters is who's willing to actually go through with the trades.  90% of the real signal is in the price.

 I usually don't stump for coins, but that one's a worthy cause that just started accepting, so I figured they were worth a plug.

Thank you for the donation. 

Sorry, I left out that you don't pay compounded fees in the second sale.  The correct number is 1.1964%.  This will come out exact IFF you buy and sell at the same price (IE, you're not losing the spread) and your fees are 0.6% (no volume discount).

btc_artist's page shows how it works much more clearly, though. 

The client doesn't support decrypting yet.  It's stubbed in to the source, so expect it in a future release.  Also, new versions of the wallet tools will probably support it.

Is it urgent?

The fees are 0.6%.  The round trip fees are 1.2036%.  Take the amount you're selling and multiply by 1.012036.  It's the same whether you're starting from BTC or USD.  No spreadsheet required. 

That protects you if your computer is stolen.  It does not protect you against wallet stealer trojans or viruses for the same reason that the wallet tools do work: the key is always stored in memory and Windows will decrypt it on the fly whenever any program wants to access it.

You should either decrypt your wallet when you want to use the tools, or store your wallet in an encrypted container (TrueCrypt, FreeOTFE, Bitlocker with a USB drive) that you only unlock when you use it.

It affects the people you send coins TO.  It also increases the code complexity of all Bitcoin clients, which will ALL need to support the new code, in perpetuity.  Optimistically, 50, 100, 200 years...  Adding alternatives has to be done very carefully.  We don't want this to turn into PGP.



Quantum computers capable of breaking ECDSA are a long, long way out.  This isn't going to sneak up on us.  We won't know if it's even possible to build such a machine for ten years.

Now IS the time to start working on the problem, but the work needs to be done in the wider crypto community to develop and test the techniques for quantum-resistance.  Good crypto algorithms take a long time to bake.

The actual technical work to implement it is very easy once we settle on the signature algorithm.  We can do it in a couple days and have it tested in a week or two.



That axiom leads me to the opposite conclusion:  It's very easy for us to make the change to the code, but the blockchain is forever.  We should not make format changes lightly.  A proof of concept on the testnet would be fine just to check for unforseen problems, but fooling with the production net now would be seriously premature.

The real work is in creating better algorithms, and it's not being ignored.

As for Bitcoin's security, there are any of a dozen things that are much more urgent to work on.  Just off the top of my head: key handling; cold storage; trust management; code auditing; refactoring.

"10 years out" isn't really when we choose to do it.  In reality it's just a tradeoff between quantum's speculated future and the maturity of quantum-resistant algorithms.

Now isn't the time: the quantum break is a very long ways out, and the algorithms aren't mature.  Any code we add we have to support forever, and any algorithm with an exploit will end up harming users who freak out about some snakeoil (like the joke that launched this thread) and thought the new signatures were "better".

I do agree that we should do it whenever there's a good, mature algorithm, even if it looks like a quantum break is still past the horizon.  NIST did a good job with AES, they're doing it again with hashes, and I'd expect DSA will be next on the list.  Barring an imminent threat, I'd much rather wait until the available algorithms are put through some serious public scrutiny.  Bad things happen when you move too fast with crypto.

Open the Bitcoin data dir:

Windows: %APPDATA%\Bitcoin
Linux: ~/.bitcoin
Mac: ~/Library/Application Support/Bitcoin/

MAKE A BACKUP of everything, then delete everything EXCEPT wallet.dat .  Fire up Bitcoin again and wait while it downloads a fresh copy of the blockchain.  It'll take a while.  Then it'll be cured.  Let us know if it's not.

When it looks like a break is plausible within ten years, we pick the best available algorithm at that time and release a new a new client that uses it for all new transactions.

When you run the new client for the first time it'll pop up a message that says "you need to forward your coins to a secure address, here's why, [yes | no]".  Publicize it so people with offline wallets get the message.

Then we wait 5-20 years to find out how many people with a high value wallet (the break probably wouldn't be worthwhile for small wallets) live under a rock.  It will be a small but lulzy number.  Since the break will likely be slow there may be time for a few people to rescue their wallets after the first one hits the news.

Then the miners start competing to build overclocked quantum computers to mine the pool of abandoned coins.  After a period of slightly increased inflation, all the lost coins end up back in circulation and life goes on.

Correct.  They're doing a lot of things different, and it'll be a while before they're mature enough to be widely trusted.  NIST is saying good things about it, though, so perhaps there's hope. 

This is only true for symmetric crypto.  AES-256 will degrade to a 128-bit level of protection, which is plenty for virtually any purpose.

For asymmetric (public key, signing) ciphers the story is grim: it will be possible to break it in about the same number of operations it takes to use it - IE, they will be completely broken.  This is true for RSA, DH and ECC.  Hopefully new algorithms will be discovered in time.

The very best quantum computers are only recently factoring 4-bit numbers, and they're enormous, slow, and very expensive.  The greatest entanglement we've achieved is 14 qbits.

Current technologies aren't scalable, and even with revolutionary technologies this is still a much harder problem than scaling silicon transistors.  I'm not convinced that it's possible.

That said, it's been doubling about every 6 years.  Extrapolating, that means we have 20-30 years to get our act together.

+1, this is much more tasteful.  Weird and gifting is much better than weird and nagging. 

It's up on their donations page, so unless they're hacked, it's real.

We also have contact through Obsi, though with due respect, he's new.



Please don't evangelize them to death, guys.  Look at it from their side - they wanted to add a new way to accept payments that some people were asking for.  We're currency geeks, but they're not, and they didn't get into this looking for new ways to purchase their office supplies.  They know Bitcoin exists now, and these guys are probably pretty good at finding things on the internet.  They have several copies of it, after all.    When they want to know more the information is widely available, and they'll find it.

Until then nagging them will only turn them off, so please just thank them for making it easy to donate and leave it at that.