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Ich möchte 2 BTC verkaufen, bin in Regensburg,
wir könnten uns in Neumarkt treffen?
aktueller bitcoin.de Kurs wäre 465.57€/Coin
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wegen "bar auf die Hand"
wo bist du denn anzutreffen?
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kann man die im Blumentopf auf dem Fensterbrett Pflanzen oder werden die dafür zu groß?
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If they had anything better than bruteforce for sha2 they would sell the technology secretly to some intelligence agency or use it to break into some online banking systems, etc.
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well, the signature checking could be done on a gpu if most of the signatures are correct. then the gpu can check all signatures and only very seldom signatures have to be thrown away becaus a previous transaction was invalid.
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but: all your layers of encryption are AES and AES is broken.
there is no practiacal attac but still, if beeing paranoid than do it right:
My way would be to use the built in encryption, and than encrypt it with true crypt using a cascade of all supportet algorithms. (after checking the whole code for backdoors...)
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Im thinking about making a Brainwallet with following technique:
take a rememberable passphrase and hash it about 100 billion times. This should take a few days on a decent cpu, and efectly render bruteforcing impossible for some years to come.
Has there been any serious analysis of the sha2 hash under this conditions? Worst case would be the chained hashing converging against some constant value...
Second problem: How high is the probability of a cpu not making a single mistake in the process?
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your math is flawed: assuming 5% error rate per step and 30 secs per step, it takes about 800hours to finish the hashing, doing as following: calculate each step 5 times, if the 5 results match continue, else start the step again. the probability to get the right result from this is: 99.999999%,
You want to play with semantics?
Ok, let's play.
Let's take a human, the super-hero kind, who can:
a/ Calculate a 32-bit operation in 10 seconds
b/ Work from midnight to midnight everyday
c/ Calculate a 32-bit operation without any errors
A hash takes about 5000 32-bit operations. So make it 10000 for ripemd160(sha256()).
That makes (10*10000) = 100k seconds = 38.4 hours = 1.6 day non-stop.
Possible.
Now here comes the fun.
This time we take a real human, the super smart kind.
A/ He calculates a 32-bit operation in 30 seconds (please try a 32-bit addition and tell me how much time it took)
This raises the total time to calculate one hash to 115.2 hours
B/ The guy must sleep, so he can "only" work from 8am to midnight.
This makes the total time to calculate one hash equal to 4.8 days.
Still possible.
C/ The lower brain failure rate in the best conditions is 5%. As he's super smart his is only 1%.
The probability of him finding the correct hash on one try is P = 1/2^(100000*1%) = 1/2^1000 ~ 1/10^300
D/ He starts the hashing calculation at birth and will stop at 100 years old.
This is (100*365) = 36500 days of calculation.
One try is 4.8 days, so he has 7604 tries available.
The odd of our super smart guy FINDING AT LEAST ONCE the correct hash in his entire lifetime is then:
R = 1-Q where Q = (1-P)^7604 = ( 1 - 1/2^1000 )^7604
Basic maths gives that Q > 1 - 7604/2^1000 = 1 - 10^(-297.149) > 1 - 10^(-297)
So R < 10^(-297) < 1/2^986
Yes, R < 1/2^986
TLDR
It's easier to crack 6 different bitcoin addresses with only 6 guesses than to a human to calculate a correct bitcoin address hash in his lifetime
Yes, I call that impossible
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Anyway, it is not possible to derive the public key and the address without using using a computer
It is quite possible to do this with pen and paper. I don't know the ripdem algorithm, but the sha and key multiplication could be done in a few hours of concentrated work(and a few hours on the next day to check). Nothing you want to do, but otherwise, if you can't trust any of your hardware, it could be the ultima ratio. |
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when are they checked for double spends or false coins? Is that when the miners put them in the block?
The miner put transactions in the block that are valid for the current blockchain. When an other pool finds a block that makes a transaction invalid, it will be exluded from the next atempt to find a block. Also if 2 or more transaction occour, which invalidates each other (double spend), each miner chooses one to include in his block |
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In a sense but your chances of winning tho lotto is 1000000 times better then mining 25 bitcoins, mining at that speed.
1 block=25 coins
Just no.. definetely not, for german "Bayernlose", the chance of winning 5000€(about 1Block worth) is 1/600.000, for costs of 1€, for solomining with an already bought Block eruptor, the chance of finding a block now is 1/83.000 a day, for 1 cents of costs per day. So a lot better than lottery. This changes when pricing in the Block eruptor, but, there are other reasenso to buy them (I use them as coffe warmer) |
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0, never even had a balance
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My Phone with the google auth for Coinlenders broke, is there a way to reset it?
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PCERCpC4SPkKyfQxFcCirbuKD3arjTQrzn
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I have 47.5 Protoshares and want to trade them for 0.3 BTC, escrow is possible.
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In so einer Situation wird oft der Ebaypreis genommen.
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1) The Problem is you can't choose your public key or your address, otherwise the whole system would be broken.
All you can do is choose a private key and calculate which address it corresponds to. Then if you don't like that address start again.
If you could choose an exact address, what would stop anyone who sees that this address has a balance from choosing the same address and spending your funds?
2) Tell us how and it will be done.
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Hi,
I've got a server with debian oldstable I7-2ksomething and a 100Mbit connection.
I'm thinking about running a bitcoin node on this server to support the network. Is it complicated to install the demon? I've noticed there is only a package in testing. With that connection I could it set to accept more than 8 conections, right? How much traffic should I expect per connection?
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