Publickey question? | Bitcointalksearch.org

aplistir

full member

Activity: 378

Merit: 197

Quote from: heitorlinks on September 06, 2017, 08:47:16 PM

I do not think it affects security, the idea of moving to a new address comes in as "spare security". Roll Eyes

It does affect security a little bit. If ECDSA will ever be cracked (eg. with quantum computer), then re-using addresses will be less secure.
New address will still be safe.

heitorlinks

newbie

Activity: 33

Merit: 0

Quote from: RentGPU on September 06, 2017, 02:44:18 PM

Thx, so now i know why satoshi said it's more secure to use the address only one time , i think this means once we make a transaction output from an address we should move the rest of the btc to a new one because this address had shown it's publickey and lost part of it's security.

I do not think it affects security, the idea of moving to a new address comes in as "spare security". Roll Eyes

RentGPU

sr. member

Activity: 661

Merit: 258

Thx, so now i know why satoshi said it's more secure to use the address only one time , i think this means once we make a transaction output from an address we should move the rest of the btc to a new one because this address had shown it's publickey and lost part of it's security.

Coding Enthusiast

legendary

Activity: 1042

Merit: 2805

Bitcoin and C♯ Enthusiast

Quote from: DannyHamilton on September 06, 2017, 03:56:09 AM

Quote from: Coding Enthusiast on September 05, 2017, 11:16:55 PM

Quote from: ranochigo on September 05, 2017, 09:01:28 PM

You can only derive it using ... a signed message.

Are you sure you can get Public key from a signed message?

Yes.

Here's a (April 2011) discussion on the topic:

https://bitcointalksearch.org/topic/ecdsa-signatures-allow-recovery-of-the-public-key-6430

Pretty interesting, thanks.

DannyHamilton

legendary

Activity: 3472

Merit: 4801

Quote from: Coding Enthusiast on September 05, 2017, 11:16:55 PM

Quote from: ranochigo on September 05, 2017, 09:01:28 PM

You can only derive it using ... a signed message.

Are you sure you can get Public key from a signed message?

Yes.

Here's a (April 2011) discussion on the topic:

https://bitcointalksearch.org/topic/ecdsa-signatures-allow-recovery-of-the-public-key-6430

amaclin1

sr. member

Activity: 770

Merit: 305

Quote from: ranochigo on September 02, 2017, 09:45:35 PM

Depends. If they send your Bitcoins to a public key (P2PK), they will obviously know your public key. I doubt this is even used anymore.

I use p2pk outputs nowadays

baryonlee

newbie

Activity: 47

Merit: 0

the public key will be showed at verify script. isn't it?

Coding Enthusiast

legendary

Activity: 1042

Merit: 2805

Bitcoin and C♯ Enthusiast

Quote from: ranochigo on September 05, 2017, 09:01:28 PM

You can only derive it using ... a signed message.

Are you sure you can get Public key from a signed message?
I have never heard of it and I can not find anything about "How" on google.

HCP

legendary

Activity: 2086

Merit: 4363

Quote from: RentGPU on September 05, 2017, 06:27:48 PM

If there is an account i dont own and i want to know the publickey ecdsa key not the hash160 , taking in consideration that this account didn't output money before so i can't know the publickey from a tx before ,sorry for my bad english

thx
Is there a way to know it's publickey which starts with 04

No. The public address is the result of a some SHA256 and a RIPEMD-160 hashes, along with the addition of some bytes here and there... http://gobittest.appspot.com/Address

SHA256 and RIPEMD-160 are both oneway hashes. You cannot get back to the public key from JUST the public address.

ranochigo

legendary

Activity: 3038

Merit: 4418

Crypto Swap Exchange

Quote from: RentGPU on September 05, 2017, 06:27:48 PM

Quote from: ranochigo on September 02, 2017, 09:45:35 PM

Quote from: RentGPU on September 02, 2017, 09:35:55 PM

Is there a way that someone know my public ecdsa key point which starts with 04 if i don't send any tx out of the address before , only recieved ?!

Depends. If they send your Bitcoins to a public key (P2PK), they will obviously know your public key. I doubt this is even used anymore.

If they send it to an address without any transactions sent from that address, no. They will only know the hash of the public key but not the public key itself.

If you sign a message with it and send it to other people, they will know your public key.

If there is an account i dont own and i want to know the publickey ecdsa key not the hash160 , taking in consideration that this account didn't output money before so i can't know the publickey from a tx before ,sorry for my bad english

thx
Is there a way to know it's publickey which starts with 04

Yes, you cannot. You can derive the Hash160 from the address but you cannot derive the public key from the HASH160.

You can only derive it using the corresponding private key, a transaction sent from it or a signed message.

RentGPU

sr. member

Activity: 661

Merit: 258

Quote from: ranochigo on September 02, 2017, 09:45:35 PM

Quote from: RentGPU on September 02, 2017, 09:35:55 PM

Is there a way that someone know my public ecdsa key point which starts with 04 if i don't send any tx out of the address before , only recieved ?!

Depends. If they send your Bitcoins to a public key (P2PK), they will obviously know your public key. I doubt this is even used anymore.

If they send it to an address without any transactions sent from that address, no. They will only know the hash of the public key but not the public key itself.

If you sign a message with it and send it to other people, they will know your public key.

If there is an account i dont own and i want to know the publickey ecdsa key not the hash160 , taking in consideration that this account didn't output money before so i can't know the publickey from a tx before ,sorry for my bad english

thx
Is there a way to know it's publickey which starts with 04

ranochigo

legendary

Activity: 3038

Merit: 4418

Crypto Swap Exchange

Quote from: RentGPU on September 02, 2017, 09:35:55 PM

Is there a way that someone know my public ecdsa key point which starts with 04 if i don't send any tx out of the address before , only recieved ?!

Depends. If they send your Bitcoins to a public key (P2PK), they will obviously know your public key. I doubt this is even used anymore.

If they send it to an address without any transactions sent from that address, no. They will only know the hash of the public key but not the public key itself.

If you sign a message with it and send it to other people, they will know your public key.

cpfreeplz

legendary

Activity: 966

Merit: 1042

Can someone know your public key if you received a transaction? Yes. Does this matter? Not usually, unless you're trying to be private or anonymous.

RentGPU

sr. member

Activity: 661

Merit: 258

Is there a way that someone know my public ecdsa key point which starts with 04 if i don't send any tx out of the address before , only recieved ?!

Topic: Publickey question? (Read 1076 times)