Questions tagged [public-key]

This tag should be used for questions regarding public keys. A public key is the public half of the public/private keypair. Anyone can use a public key check that a signature is correct, but they can't generate the signature themselves with the public key.

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70
votes
4answers
33k views

What is a compressed Bitcoin key?

The standard Bitcoin client in version 0.6 apparently introduces compressed keys. What are they? Are there any drawbacks to using them? Any incompatibilities with older software? Reductions in ...
59
votes
6answers
22k views

What is relation between scriptSig and scriptPubKey?

Scenario: A is sending 1 BTC to B. scriptSig appears in the Input Script. scriptSig = <sig> <pubKey> Here, public key is the Public Key of the sender, A. (this is the public key ...
29
votes
5answers
18k views

How are public & private keys in an address created?

I understand the high level concept I am more interested specific details. How is a private key generated. How exactly is public key generated, how is address generated from public key.
24
votes
1answer
4k views

Why does hashing public keys not actually provide any quantum resistance?

In the discussions about taproot, it was mentioned that outputs will include the public key directly instead of hashing them. It is stated that, currently, hashing does not really provide quantum ...
23
votes
3answers
35k views

Is it possible to get the public key of a bitcoin address I do not have the private keys for with the standard client?

It is possible to get it from here: https://blockchain.info/de/q/pubkeyaddr https://blockchain.info/q Is it possible with the standard client? How? I am aware that the blockchain only contains the ...
22
votes
2answers
54k views

How are public and private keys related to the wallet?

I understand that all the Bitcoin protocol is based on an asymmetric cryptography. A user gets 2 keys (public and private). How do these keys connect to the Bitcoins? How are the keys are related ...
20
votes
1answer
15k views

What is a private key and a public key?

What exactly is a private key and public key in relation to Bitcoin? What are they, how are they used, and how does one find out what their private and public keys are?
19
votes
2answers
15k views

Why does the length of a bitcoin key vary?

Why does the length of a bitcoin key vary? Why aren't they all the same length?
17
votes
2answers
5k views

Why do you use Bitcoin addresses instead of public keys?

Why do you hash the public key twice? Are there security benefits to abstracting away from the public key? Is it because the address can represent multiple things? I'm missing something. Could you ...
17
votes
2answers
15k views

Does a wallet containing multiple addresses have a single private key?

Title says it all. Would one private key enable you to recover all the addresses in your wallet? Or does a wallet just contain a series of key-pairs?
16
votes
1answer
3k views

Can private keys remain offline for their entire life?

I am new to Bitcoin and this question is based on 3 assumptions that may be incorrect. Assumption 1: If I understand correctly, the Bitcoin address is generated algorithmically independent of the ...
14
votes
3answers
7k views

Key derivation in HD wallets using the extended private key vs hardened derivation

I am reading the book Mastering Bitcoin and confused about wallet key derivations in Chapter 4. Keys, Addresses, Wallets. The book first mentions a private child key derivation where the child ...
14
votes
3answers
20k views

All Bitcoin Public Keys with non-zero balance

I want to get a database or otherwise retrieve a set off all bitcoin public keys (not addresses) that have non zero balances. What would be the easiest way to do that? Is there an API that could do ...
13
votes
1answer
2k views

What are the potential attacks against ECDSA that would be possible if we used raw public keys as addresses?

According to this answer about why addresses are hashes rather than public keys there are potential attacks that are possible if you have the public key rather than the address, what are these attacks?...
13
votes
3answers
3k views

How would one "Encrypt" a message using a Bitcoin *public key* and use its private key to decrypt it?

I have the following text string: This is a test message. Using my bitcoin public key (bitcoin address?), how can I encrypt this message? How would I decrypt the message using a bitcoin private key?
12
votes
2answers
978 views

How would we know the real Satoshi?

Should Satoshi decide to reveal his or her true identity, how can one know the person is the real creator of Bitcoin, rather than a person who hacked the forum login, email address or the like? In ...
11
votes
2answers
3k views

Why are Bitcoin addresses starting with 1s or 1S so rare?

I've generated 10000-50000 key pairs using Chrome Bit Kit app or www.bitaddress.org and have noticed the scarcity of public keys which begin with 1S and/or 1s. Why is this the case?
11
votes
5answers
4k views

What would happen if you send bitcoins to a non-existent Bitcoin address?

If one were to send bitcoins to an address that has not been created yet, what would happen? Would the coins be lost forever? Would they just sit there until the address and key pair are generated?
10
votes
3answers
7k views

parsing bitcoin input and output addresses from scripts

can someone walk me through the process of combining script inputs and outputs to reveal the base58 encoded input and output addresses. take for example, block 728. this has two raw script inputs: ...
10
votes
2answers
2k views

How does ScriptPubKey know the public key of an Bitcoin address?

I am currently having a blonde moment. The ScriptPubKey provides a hashed version of the receivers public key. scriptPubKey OP_DUP OP_HASH160 OP_EQUALVERIFY OP_CHECKSIG However, if I give ...
9
votes
2answers
38k views

How do I get my public address in Bitcoin Core?

In a world of pain at the moment. I downloaded Bitcoin Core, and before I realised I'd need the complete downloaded Blockchain, my friend transferred some coins to my address. I did some research ...
9
votes
2answers
9k views

Public Key + Private Key enough to backup?

I invested in bitcoins and unfortunately I have problems to understand the system. Perhaps you can answer me the following questions? 1.a) I know my public and my private key. Do I still have to ...
9
votes
2answers
11k views

What if duplicate wallet addresses are created? [duplicate]

I'm a newbie to Bitcoin, so I apologize if this seems like a "noob" question. So, from what I've read: anyone can create a new Bitcoin wallet. Upon creation, a wallet address is automatically ...
8
votes
1answer
3k views

When importing private keys, will compressed or uncompressed format be used?

I am looking into implementing support for compressed public keys on Vanity Pool. However, I have my concerns about importing solutions into a desired vanity address under that format. From what I can ...
8
votes
3answers
16k views

Is it possible to use xpub address to monitor balance from previously generated addresses?

I'm trying to find a way where I can view balance of my ledger nano s wallet without always attaching it to computer all the time. I found something called xpub address which allows me to generate ...
8
votes
2answers
11k views

What exactly happens when a new wallet is created?

I am asking for what is being created when there is a new wallet created. And the second part of my question is considering public key. Is the public key the same thing as the address? I read that ...
8
votes
2answers
5k views

How can I get the uncompressed public key from the compressed public key in openssl?

Given a private key, I can get the uncompressed or compressed version of the public key like so. EC_KEY* pKey = EC_KEY_new_by_curve_name(NID_secp256k1); std::vector<unsigned char> getPubKey(...
7
votes
1answer
5k views

difference between Master Public/private Key and Public/private Key?

what is difference between Master Public Key (MPK) and Public Key? what is difference between Master Private Key and Private Key? should I use master public key (MPK) when generating address or public ...
7
votes
1answer
786 views

How to get the Public Keys of a bitcoin User

Is there some way in which I could get the public key of a Bitcoin user ? Lets say I have transaction with another Bitcoin user. Is there some means by which I can retrieve the public key of the ...
7
votes
2answers
4k views

python-bitcoinlib | Create Private Keys, Public Keys and Addresses - How to Do It?

I'm trying to use the python-bitcoinlib library but its docs aren't entirely clear to me. I'm a programmer but quite new to Python, and not very versed in the Bitcoin protocol. What's the process, ...
7
votes
1answer
9k views

How to generate specific private keys from 12-word backup and wallet address?

A single seed can lead to billions of addresses. Some wallets are unable to scan and find all used addresses. Is it a way to infer the private key from 12-word backup and wallet ID / (public key). ...
7
votes
1answer
1k views

If addresses are hashes of public keys, how are signatures verified?

I've skimmed through the https://en.bitcoin.it/wiki/Protocol_specification and it seems that when sending someone bitcoins, I would sign the transaction data (not quite sure which parts exactly) with ...
6
votes
2answers
16k views

Does the private key of Bitcoin change everytime the address changes?

I have read from many sites that an address should change every time a Bitcoin transaction is made. Does the private key change along with the Bitcoin address. How is the address obtained from the ...
6
votes
2answers
5k views

What are the DER signature and SEC format

I often see those 2 elements in bitcoin documentations and tutorials but I have not yet find a proper definition on the internet for DER signature and SEC format.
6
votes
2answers
914 views

Why can't we switch private and public keys?

If private and public keys are performing the same task (although asymmetrically), but I mean each one can encrypt something that only the other one can decrypt, can I create a paper wallet and share ...
6
votes
2answers
3k views

Why is it impossible to derive public key from address?

This is my first bitcoin transaction. Why this transaction doesn't show my public key? help message on the same page says that, It's impossible to determine the public key from a Bitcoin address, ...
6
votes
1answer
4k views

What makes an extended public or private key?

I was under the impression that an extended public key was comprised of the public key + chain code, and I'm unfamiliar with what comprises the extended private key. However this does not seem to be ...
6
votes
1answer
7k views

How to get public master key of a Ledger wallet?

I have a ledger Nano S and would like to know how to extract the public master key of its wallet, in order to do HD key derivation in an external process. Is there a way or is this info never exposed ...
6
votes
2answers
505 views

How many different formats can a public address take?

I'm creating an offline index to report off of the block chain. I plan on indexing each transaction based on the address displayed in the TX. Are all addresses Base58? I believe I also read about ...
5
votes
1answer
3k views

How can a deterministic wallet have one private key but multiple public keys

If we take for example bread wallet. There is one mnemonic to remember, which means one private key? But when you use the app, your public address constantly changes. So more than one public key? ...
5
votes
2answers
574 views

How does Nextcoin convert 256-bit Curve25519 public keys into ~20 arabic numerals?

Nextcoin seems to convert 256-bit Curve25519 256-bit public keys into "account numbers" that have only arabic numbers and seem to only have a length of 20. How is that done? Examples In the ...
5
votes
3answers
408 views

How does ImportPrivateKey get the Address if I don't explicitly send it?

Suppose I just used vanitygen to create this key: Pattern: 1a Address: e1aMGYXuGpUwDGH9gz3ZBs8UH746nRdEk6 Privkey: 5KhCszBi22hEZZixPEQkLAMtUVkxbGaxBFsH7a9iefqrxHmSXgH All I had to do to import this ...
5
votes
1answer
113 views

Isn't bribe smearing possible because no payee signature is required?

The Bitcoin protocol does not require the payee to sign for a payment; only the payer signs (the payer signs a hash of the payee and payer's public keys). In other words, a payee signature is not ...
5
votes
1answer
18k views

How can I convert a bitcoin public key to a bitcoin address?

How can I convert a bitcoin public key to a bitcoin address? Note: I am using PHP. Is there an existing bitcoin API or PHP-API to do that converting ?
5
votes
2answers
6k views

How to generate Ed25519 public key from private key using libsodium?

Not all crypto currencies are using secp256k1 technology for keypair generation and digital signatures. Curve25519 technology (frequently used to support ECDH key exchanges) is being used by a few ...
5
votes
1answer
543 views

Derive new public keys from a public key?

This article says you can generate new public keys from an already generated public key. How is this possible? https://bitcoinmagazine.com/articles/deterministic-wallets-advantages-flaw-1385450276 ...
5
votes
1answer
745 views

Can we derive parent’s private key using child’s private key?

In the book named Mastering Bitcoin by Andreas, the author described the usage of derived child keys. One thing I noted was that he said(page 108), The derivation function is a one-way function, ...
5
votes
1answer
552 views

What is the use of hashing the public key to obtain the bitcoin address?

What is the use of hashing the public key to obtain the bitcoin address (except to compress it) rather than using the public key directly? Why not deal with public keys directly?
5
votes
1answer
2k views

Generate addresses without private key: Stealth addresses vs Master Public Key

In my case a store owner has different POS terminals. On none of the terminals should be a private key stored! The owner has one wallet, where he wants to get all transactions aggregated, done on the ...
5
votes
1answer
897 views

Trying to create a bitcoin public/private key using bitcoin-core

I want to create a single bitcoin address to which I can send and receive funds too. Using the bitcoin-core console, I typed in the following: Input: getnewaddress Output: Address: ...

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