<p>The first out-going transaction for an address claims the address. To make such a transaction, you need to know a private key for the address. The first transaction causes the corresponding public key to be stored against the address in the block-chain, and then subsequent transactions are only accepted if they have the same public (and hence private) key.</p>

<p>The addresses are 64-bit, which would probably take a few years to crack by brute force. The public and private keys are 256-bit.</p>

CC BY-SA 3.0
2014-07-07T13:01:27.977Z
2014-07-07T13:01:27.977Z
Brangdon
<p>Apparently, <a href="http://cryptolife.net/in-depth-analysis-nxt/" rel="nofollow">NTX uses very short addresses and a very small alphabet</a>. There is a system designed to claim ownership of a given address, but I couldn't find much information on it. How is it handled in the NXT system?</p>

CC BY-SA 3.0
2014-03-14T06:15:03.397Z
Just speculation, and not an answer, this could be possible using something like firstbits. The address could actually be 32 characters long in the block chain but doesn't allow any address to be used if there's another with the same first 20 characters. Either the limited alphabet could slow down the time it takes to generate a valid address, like finding a name with vanityminer, or acceptible character substitutions could be used. a, b or c could show as 1; d, e or f could show as 2, etc.. kind of like good old t9 if you remember that.
Mark
CC BY-SA 3.0
2014-03-19T00:35:01.777Z
Voting to keep open. Knowing how public keys are converted to 20-digit addresses does not tell you how to let the network know you're claiming an address.
Tony
<address><nxt><ownership>
How does one claim ownership of an NXT address?
ThePiachu
# How does one claim ownership of an NXT address?

(Asked by: username_0 on 2014-03-14)

Apparently, [NTX uses very short addresses and a very small alphabet](http://cryptolife.net/in-depth-analysis-nxt/). There is a system designed to claim ownership of a given address, but I couldn't find much information on it. How is it handled in the NXT system?

**Tags:** address, nxt, ownership

> **Comments:**
> **username_1**: Just speculation, and not an answer, this could be possible using something like firstbits. The address could actually be 32 characters long in the block chain but doesn't allow any address to be used if there's another with the same first 20 characters. Either the limited alphabet could slow down the time it takes to generate a valid address, like finding a name with vanityminer, or acceptible character substitutions could be used. a, b or c could show as 1; d, e or f could show as 2, etc.. kind of like good old t9 if you remember that.  
> **username_2**: Voting to keep open. Knowing how public keys are converted to 20-digit addresses does not tell you how to let the network know you're claiming an address.  

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## 1 answers

### Answer by username_3 on 2014-07-07. Score: 2 | Accepted answer

The first out-going transaction for an address claims the address. To make such a transaction, you need to know a private key for the address. The first transaction causes the corresponding public key to be stored against the address in the block-chain, and then subsequent transactions are only accepted if they have the same public (and hence private) key.

The addresses are 64-bit, which would probably take a few years to crack by brute force. The public and private keys are 256-bit.


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