custom bitcoin address wanted

[tsupp4]

Hello community,
as offered here I have experienced it's possible to create custom bitcoin bitcoin addresses. I've contacted the seller but it seems he can't help me at the moment.

I want a bitcoin adress, after the starting 1-digit, with 7 certain case-sensitive digits. Whoever is able to create such addresses and tell me how to import them to my wallet, please contace me via PM, you can name your price for this service, I'll be generously.

[vuce]

https://bitcointalk.org/index.php?topic=25804.0

you will not be able to get 7 digits though.

Also you will not be able to get an address without a private key, therefore you're risking loosing everything on it "buying" this from a third party.

[tsupp4]

Thank you.

you will not be able to get 7 digits though.

Isn't this a matter of time and key generating power?

[CIYAM]

Isn't this a matter of time and key generating power?

Correct (but the difficulty dramatically increases per character).

You can generate an address with 5 leading characters (after the 1 of course) with just an average computer using vanitygen.

I did it using an average 2 year old laptop in about 4 days.

[vuce]

Thank you.

you will not be able to get 7 digits though.

Isn't this a matter of time and key generating power?

Well yes. It took me about 15 minutes to get to 5 digits, I imagine it would take quite a bit longer to get to 7. But I guess it can be done, eventually.
But as I said, I wouldn't trust anyone else with this, so do it yourself.

[CIYAM]

Well yes. It took me about 15 minutes to get to 5 digits...

Wow - guess my laptop computer is rather slow then.

[vuce]

Well yes. It took me about 15 minutes to get to 5 digits...

Wow - guess my laptop computer is rather slow then.

It ran on quite a decent GPU, so there really is no comparison

[Blazr]

Well yes. It took me about 15 minutes to get to 5 digits...

Wow - guess my laptop computer is rather slow then.

I played around with vanitygen, and from my experience it appears that the length of custom text you want isn't important, some addresses just took longer to generate than others, regardless of the number of vanity characters.

[vuce]

Well yes. It took me about 15 minutes to get to 5 digits...

Wow - guess my laptop computer is rather slow then.

I played around with vanitygen, and from my experience it appears that the length of custom text you want isn't important, some addresses just took longer to generate than others, regardless of the number of vanity characters.

The algorithm is really "dumb", it just generates addresses and stops when it finds one that matches the pattern. Difficulty grows with length (imagine trying to find a certain address from first to last digit, chances of finding it are almost non-existent), but there's quite a bit of variance in this, it might take 1 second or it might take 1 hour to find the same pattern (just like block mining).

[JoelKatz]

Also you will not be able to get an address without a private key, therefore you're risking loosing everything on it "buying" this from a third party.

If it's done right, the party generating the address for you has no access to the private key, only the public key.

It works like this:

1) You generate a random 256-bit integer less than the SECP256k1 generator. You keep this secret. (Effectively, an ECDSA private key.)

2) You compute the corresponding EC point on the SECP256k1 curve. You share this with whoever is finding the vanity address for you. (This is the ECDSA public key that corresponds to the private key you generated in step one.)

3) The person working out the vanity address for you tries various 256-bit integers also less than the SECP256k1 generator. They compute the corresponding EC point and add it to the EC point you sent them (from step two). They then hash this and see if it produces the desired vanity address. They repeat this over and over until they find a 256-bit integer that works. They give this integer to you. (And the world, it need not be kept secret.)

4) You add the 256-bit integer they found to the 256-bit integer you generated in step 1 and reduce it modulo the SECP256k1 generator.

5) You now have the private key, and they don't. (And you can prove that they cannot generate the private key from just the information you gave them unless ECDSA is fundamentally broken.)

In ECDSA, you convert a private key to a public key by multiplying by the generator. Division is impossible.

The vanity address generation scheme above works because: (A+B)*G = AG + BG

You generate A and AG, but give them only AG.

They try various different B's, calculating the AG+BG for each one to find the right one for the vanity address.

They give you B. You can now compute A+B (the secret key corresponding to the public key AG+BG) but nobody else can since they do not know A.

Computing A from AG would mean breaking ECDSA fundamentally. All you gave them is AG, an ECDSA public key. If they could figure out the private key to your new account (A+B), they could also figure out A. So if they could figure out the private key to your vanity account, they could also figure out the private key you created in step 1. But all you gave them was the corresponding public key. So any compromise of the vanity account would mean they could compromise a private key given only its corresponding public key.

[TehZomB]

My name is 7 digits.
With my GPU, case-insensitive I found 1 TehzoMB in 24 hours.
When I didn't set the case-insensitive flag, the ETA for a 50% chance of finding a key was two years. You might want to rethink what you're asking for. <-- wrong info/name/prefix/aaah

[rjk]

Doesn't anyone have a farm optimized to run Vanitygen yet? They could sell their services. For optimizations, you just need to overclock and make sure your memory is clocked up as well. It should run very fast on a 7970.

[mc_lovin]

I can probably find this for you, I've generated some and I have vanitygen installed.  I have up to 7.7 GH/s here and I'm sure I found find 7 digits (or at least try!)

What's the bounty on this?

[Serge]

i wouldn't trust anybody else generating private key for me, unless maybe if it's done how JoelKatz describes above

if you have good or decent GPU just use vanitygen software yourself and if 7 chars estimate is too long, try to come up with shorter alternatives

my 5800 GPU took couple of hours generating 6 char. vanity gen address without overclock settings, i generated 2 such addresses each taking roughly 2 hours to find, 4 and 5 chars were found extremely fast.
7 char could take much longer, up to few days i think with 5800 series card for instance

[jamesg]

I got 7 characters no problem for my vanity addy using a single 5850 and vanitygen.

1GigavpsDjLBQJzHenH3zPq3EwkENL9tQS

[DeathAndTaxes]

Well yes. It took me about 15 minutes to get to 5 digits...

Wow - guess my laptop computer is rather slow then.

I played around with vanitygen, and from my experience it appears that the length of custom text you want isn't important, some addresses just took longer to generate than others, regardless of the number of vanity characters.

There is an element of luck however the length of the custom text most certainly affects difficulty.  The average search time grows with each digit.

A case sensitive search will require 58^(length) attempts on average.

[johnlu]

And... How can we add this address to our wallet?

[Blazr]

And... How can we add this address to our wallet?

You can import the private key. Each client has a different way of doing that.

[Serge]

And... How can we add this address to our wallet?

quite simple, even on windows, assuming using official bitcoin client:

• shutdown Bitcoin-QT client
• start bitcoind.exe (leave this blank terminal bitcoind.exe screen open while doing next steps)
• in new Command Prompt window navigate to bitcoind.exe location, by default it's something like C:\Program Files (x86)\Bitcoin\daemon>
• type following in command prompt:
  
  C:\> bitcoind importprivkey <bitcoinprivkey>
  
  where <bitcoinprivkey> is your newly generated private key for the vanitygen address you just generated
  
  
• it's going to take few moments, after it's complete, you can shutdown bitcoind from windows task manager processes or just typing "bitcoind stop" in the command prompt
• start bitcoin client again, you should be able to see your vanitygen address in there

[CIYAM]

• it's going to take few moments, after it's complete, you can shutdown bitcoind from windows task manager processes or just typing "bitcoind stop" in the command prompt

On my rather lame laptop this took much more than a few moments (I thought it had hung and killed the task after 10 minutes).