Bitcoin Forum

Bitcoin => Development & Technical Discussion => Topic started by: codymanix on November 25, 2011, 09:19:43 PM



Title: Structure of bitcoin adresses
Post by: codymanix on November 25, 2011, 09:19:43 PM
I recently noticed that all bitcoin adresses start with the digit "1"?
I always thought, these adresses are just hash values used as public keys, so they should be very randomly distributed?


Title: Re: Structure of bitcoin adresses
Post by: Akemashite Omedetou on November 25, 2011, 09:46:24 PM
An address does indeed represent a result of a hash function, which has of course very high entropy, but this representation is a little more structured.
Basically there is the 1 in the beginning of every address so that it will be possible to quickly visually distinguish a mainchain- bitcoin address from for example an address on the testnet (which start with "m" or "n") or a private key (which start with "5") or even any other basexx encoded stream of bits.
This is described in more detail on https://en.bitcoin.it/wiki/Address (https://en.bitcoin.it/wiki/Address)


Title: Re: Structure of bitcoin adresses
Post by: DeathAndTaxes on November 25, 2011, 09:48:54 PM
The address isn't just a hash.  It is a hash of the private key but a checksum and header (the 1) are added to indicate the address type.


Title: Re: Structure of bitcoin adresses
Post by: Atheros on November 26, 2011, 12:47:57 AM
This page is better:
https://en.bitcoin.it/wiki/Technical_background_of_Bitcoin_addresses


Title: Re: Structure of bitcoin adresses
Post by: robocop on November 27, 2011, 04:22:15 PM
The principle isnīt a very old principle which used for example to encrypt files, drives or data streams. In all cases every side must have the hashcode for the right checksum.

So it is a little bit curious that the bitcoin wasnīt found much earlier.

Maybe one reason is that the worldwide web, online shopping, smart phones which were increased significantly.
Another reason is that the fiat money system is blowing up and more and more guys search an alternative money system.


Title: Re: Structure of bitcoin adresses
Post by: gmaxwell on November 27, 2011, 04:50:39 PM
The principle isnīt a very old principle which used for example to encrypt files, drives or data streams. In all cases every side must have the hashcode for the right checksum.
So it is a little bit curious that the bitcoin wasnīt found much earlier.
Maybe one reason is that the worldwide web, online shopping, smart phones which were increased significantly.
Another reason is that the fiat money system is blowing up and more and more guys search an alternative money system.

There is a lot more to bitcoin than just how addresses are computed. The byzantine agreement algorithm bitcoin uses is novel and was the missing piece that prevented bitcoin from being invented in the 90s.


Title: Re: Structure of bitcoin adresses
Post by: DeathAndTaxes on November 27, 2011, 05:52:42 PM
There is a lot more to bitcoin than just how addresses are computed. The byzantine agreement algorithm bitcoin uses is novel and was the missing piece that prevented bitcoin from being invented in the 90s.


Exactly.  There are essentially two problems to a distributed currency
1) ensure transaction is valid - very easy to solve w/ private keys.
2) ensure coins are only spent one - very difficulty to solve.  Bitcoin uses the proof of work and placing transactions into blocks to reach consensus on the location of all coins at any particular point in time.



Title: Re: Structure of bitcoin adresses
Post by: robocop on November 27, 2011, 07:56:25 PM
yes the bitcoin is more than I have explained but I the (simply) key + hash = checksum make it possible.