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1  Bitcoin / Bitcoin Discussion / The first Bakkt Bitcoin Futures trade on: September 23, 2019, 07:26:20 AM

Finally, it's lived now. I wonder what will happen in the next few hours after this. Will it affect the bitcoin price, and we will see the next higher price, or it will remain like the price now?

What do you think, guys? I don't know if the news is real or not, I just read on twitter Grin

Source : https://twitter.com/Bakkt/status/1175938226554658824?s=19
2  Bitcoin / Legal / What if bitcoin addresses can be hacked on: September 29, 2012, 06:21:56 PM
Culculations how much faster the hardware needs to be to proof I can't just crack a bitcoin address :

I've found at https://en.bitcoin.it/wiki/Technical_background_of_Bitcoin_addresses how an address is calculated.
To generate a specific address that already has bitcoins I need to calculate at average 2^160 keys.

At http://www.bitcointrading.com/forum/bitcoin-software/vanitygen-vanity-bitcoin-address-generator-%28v0-17%29/ how quick addresses can be generated.
The fastest graphics card for this has a rate of 23.5 Mkeys/second.

So lets round the generating speed to the nearest 2^x speed, we get 2^24 keys/second.
On average we need 2^160 / 2^24 = 2^136 seconds, or more understandeble human language, more time than the universe exists.

If I want to be able to crack an address in less than a day, for example a little over 18 hours (to get a nice 2^x seconds), I have 2^16 seconds to do it so I need to be 2^136 / 2^16 = 2^120 times faster than with the current hardware.

If I take into account that at the moment hardware still get 2 times faster each 1.5 yeah, I need to wait 180 years for hardware capable of breaking a bitcoins address within one day.
So technically it is not (yet) possible to do this kind of thing.

My actual question
What if someone or something is able to do this kind of calculations, and thus can spent every coin mined today, or is just very very very lucky and finds someone elses keys without hacking into other computers.
Will it be legal to spend the coins?
3  Alternate cryptocurrencies / Altcoin Discussion / Litecoin proof of work on: May 15, 2012, 10:25:25 AM
I'm interested in the proof of work concept used in the cryptocurrencies.
The one used for bitcoin I understand and implement if I want.
The one used for litecoin is a bit harder to find.
Until now I just find I should replace the sha256(sha256(block of 80 bytes)) with scrypt(block of 80 bytes).
The problem is the scrypt hash, I can't find a clear description.
I know it somehow generates a pseudo random block of data with a length of 128kB and does some pseudo random mixing of that block.
The sourcecode of the cpuminer I found is to optimized for me to read.
Does anyone have a link to some pseudo code like the one on http://en.wikipedia.org/wiki/Sha256 but for scrypt?
4  Bitcoin / Mining / Possible attack to disrupt difficulty? on: March 26, 2012, 10:30:36 AM
Blocks can have an older timestamp than its previous block.
One example is this :
http://blockchain.info/block-height/171759 Timestamp 2012-03-18 19:31:32
http://blockchain.info/block-height/171760 Timestamp 2012-03-18 19:31:30

How much older can timestamp be?

If someone generates the last block of a difficulty with a timestamp of the first block of that difficulty plus 10 minutes the difficulty would get 2016 times as high.
If he adds less it would become even harder.

For this attack you don't need anything like 51%, just x% power of the network gives x% chance to do it, so in theory everybody can success with enough luck.
5  Bitcoin / Development & Technical Discussion / Protocol used for pool mining on: February 03, 2012, 08:35:53 PM
I'm trying to find the protocol or api used by the different miners to get work from the different pools but I can't find it.
Can anyone point me in the right direction?
Soap? json? something else?
6  Bitcoin / Wallet software / SHA256 implementation fails on 2 of 9 tests on: January 28, 2012, 11:46:43 PM
I've build a little C# project to try to implement SHA256 myself and tested it with test vectors from set 1 from
https://www.cosic.esat.kuleuven.be/nessie/testvectors/hash/sha/Sha-2-256.unverified.test-vectors
I used the pseudo code from http://en.wikipedia.org/wiki/SHA-2

Vector 5 and 6 fails for my program with the following output :

Test failed for string : abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq
Expected hash 248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1
Result was    e9ee317b2c7807407297320147508a0e5becd7d32e27cafd66c6fd9635cc2c88
.Net version  248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1

Test failed for string : ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789
Expected hash db4bfcbd4da0cd85a60c3c37d3fbd8805c77f15fc6b1fdfe614ee0a7c8fdb4c0
Result was    2f3d5a2408f1a3aadc21629aaf4f261b80e0ad096214efcbf0d6ae202d39eb0b
.Net version  db4bfcbd4da0cd85a60c3c37d3fbd8805c77f15fc6b1fdfe614ee0a7c8fdb4c0

Expected hash is the hash on the website with tests, result is my own calculated hash, .net version is the hash calculated with .net's System.Security.Cryptography.SHA256.
I can find many websites that just tell me the same thing, my hash is wrong.
I've tried to find it with debugging but I really have no clue where to look since the other 7 tests run just fine.

Can anyone supply me with the w[0..63] values and the a/b/c/d/e/f/g/h values for each of the 64 loops?
7  Other / CPU/GPU Bitcoin mining hardware / FPGA specs needed for bitcoin mining on: January 23, 2012, 10:43:12 AM
I'm interested in bitcoin mining, especially in fpga mining, and I am thinking of trying to implement it myself.
I've borrowed an old xilinx spartan 3 fpga board from a friend of mine and have made a few simple small designs for it just for fun.
Now I am wondering if bitcoin mining will fitt in the board, but I don't really have an idea how big bitcoin mining will be and if it will fit in this fpga.
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