Bitcoin Forum

Why does bitcoin use public keys as pseudonyms? Is there any reason for that? What are the advantages of using public key as the pseudonyms? Highly appreciate if someone can give me an answer.

Repharse plz.

Attaching a name to a public key requires an additional step and some kind of registration system. Bitcoin doesn't bother, but it can be done outside of the Bitcoin protocol. There are already sites that support giving names to addresses, such as blockchain.info and bit.co.in.

Bitcoin uses the hash of a public key as addresses.

I agree you should rephrase your question.

Maybe this answers your doubt: Public keys are what you send something to, so you can't deviate too far from it without breaking the "sending to" part of a public-private-key architecture.
As the recipient of the transaction only has to proof ownership of the private key to a public key provably related to an address the moment he wants to use his address, it is not actually necessary to have the public key as the address itself but it necessarily has to be related "beyond any doubt". Different public keys map to the same address but they can not be generated efficiently without alien technology or millions of years of computation.

Let me answer this question with a question...
Why do you need a Bank Account Number, instead of giving the other guy your name? :p

The BTC Address is derived from the public key.  The public key is derived from the private key.  Gotta have a key pair (a public key and a private key) to use asymmetric cryptography (also known as public-key cryptography (http://en.wikipedia.org/wiki/Public-key_cryptography)).  Public keys are required to validate the digital signatures of transactions.  One advantage of using a public key as a pseudonym is that it doesn't reveal any Personally Identifiable Information (http://en.wikipedia.org/wiki/Personally_identifiable_information) and therefore helps prevent identity theft.

a bitcoin address is random characters due to it being derived by a hash of 256bit private key and other bits inbetween.

to make a bitcoin address username length (under 12 characters for instance) the hash of a private key would only be 64bit or smaller.
(security risk)

also (referencing vanity gen)
if you wanted a public key that was just 12 specific characters it would have to be 'reverse engineered' in th same way vanitygen does it.

but with being only 12 digits and using a easy to 'reverse engineer' encryption such as 64bit. the basic problem is, that if you can get your username/privkey pair in a matter of minutes....... so can everyone else!

the only solution would be that we stick with the current secure system but have a third party 'address book' that links usernames to bitcoin addresses. and then try lobbying wallet developers to incorporate an API into their wallets so that when you type in a username, it API calls that username's linked address. and then fills in the Send to: box in the wallet with the bitcoin address.

so an address book/directory database is the safest option

One reason hinted at above: collisions.

Practical database design, Part 1 By: Philipp Janert http://www.ibm.com/developerworks/web/library/wa-dbdsgn1.html (dead link)

- http://www.jroller.com/charlie.li/entry/practical_database_design_part_1

Arguably, Bitcoin users are supposed to change addresses over time. The Addresses don't identify a specific user: but a place to send the output of a Bitcoin transaction. The resulting "coin" from the transaction:output pair does not change over time (though it may be spent).

Edit: it should be noted that some addresses; particularly Pay-to-Script hash addresses, may be under the control of more than one person. In that case, the address is not really a pseudonym at all.

I don't think it is even real problem. There were all kind of different possibilities do deal with it and they decided to do it this way. I think it is just fine.

Actually I don't think what would be other, better possibility.

The advantages are that it makes it possible to verify that the sender of a TX truly controls the address that controls the coins. It prevents the double spending problem that other P2P payment methods have that are not centralized.

Public keys in bitcoin are ephemeral. It's broken and wrong to reuse them.

because trying to pronounce your name tdumdiu is bad enough. imagine if your name was 5 times longer. people would not want to mention your name :D