Bitcoin Stack Exchange
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Questions tagged [public-key]

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.

A public key is the public half of a public/private ECDSA keypair. It is meant to be shared and without revealing the private key. Public keys can be used to verify a digital signature and encrypt data that can only be decrypted by the private key.

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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 pubkey after a tx from that address.
kermit
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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?
shoeless joe
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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 getPubKey(EC_KEY* pKey, bool compressed) const { if…
user299648
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ripemd160(sha256(publickey)) - Where am I going wrong?

(Note: I'm using http://www.royalforkblog.com/2014/08/11/graphical-address-generator/ (use "bitcoin" as the phrase for generating the private key) I'm trying to take the first step in going from a publickey to an address. For example, if this is my…
inersha
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How do I find the public key of a bitcoin address?

I want to know the public key of my bitcoin address, (e.g. 13mtYzgprJuLUWw1EVWSPPuC88q7fGuSX1), how do I do that?
h__
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On public keys compression, why an even or odd y coordinate corresponds to the positive / negative sign respectively?

This is a paragraph from Andreas' book on compressed/uncompressed public keys. Chapter 4 - Section - Key Formats Whereas uncompressed public keys have a prefix of 04 ,compressed public keys start with either a 02 or a 03 prefix. Let’s look at…
chdimosthenis
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How to uncompress a public key?

Simple question but I couldn’t find the answer anywhere. What’s the 65 bytes version of those public keys ? 0229b3e0919adc41a316aad4f41444d9bf3a9b639550f2aa735676ffff25ba3898 02f15446771c5c585dd25d8d62df5195b77799aa8eac2f2196c54b73ca05f72f27 which…
user2284570
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Can someone find out how much bitcoin do I have using my public key?

Im pretty new to bitcoins, so I may have a silly question. Imagine that someone has my public key. Can he find out how much bitcoin do I have? only using my public key?
eylay
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What if two public keys have the same hash？

What if two public keys have the same hash? Although the chance is very very small, I am still interested in what would happen. Suppose that Alice makes a transaction to Bob using Pay To Public Key Hash (P2PKH) style signature script. But Carmen has…
Bill
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How can a sender know receiver's public key when creating "Pay To Public Key" tx?

When you create a "Pay To Public Key" transaction, you need to know the receiver's public key. How can we know receiver's public key? You can get public key hash from address like this, but I'm not sure how to get public key. FYI: scriptPubkey in…
Satoshi Nakanishi
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Public key with 142 characters?

I've read that public keys that bitcoin uses have 130 characters (65 bytes), but on the page: http://blockexplorer.com/tx/7e9bf03454b9ff80974d39d02a8088154e60ee65726e239f70341366d1a1ccf7 I've found a public key:…
godlark
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Does every private key have two public keys (ie Y and negated Y?) (secp256k1)

given a private key Z that multiplied by the generator point G gives a public key P fulfills x^3 + 7 being a square, is it safe to say that either (x,y) is a valid point / pubkey, or (x, curve p - y) is a valid pubkey, and so recovering a pubkey…
user16318248
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Has a spend from a hybrid public key ever made it to the blockchain?

If so, could you please give the TXID of a transaction that spends from a hybrid public key?
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Retrieving an addresses' public key from Pkscript/sigscript/witness

Let's use this transaction as an example. In the transcation, address 3GGoy8NoCF62TCAPGidWMU3u1ZrgwmasFt has a pkscript, a sigscript and a witness. It is possible to use any one of these, or some combination of them to retrieve that address' public…
DUO Labs
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What can be bitcoin's secret can be at most and at least?

We know that: S(Secret-Scalar) x G(Generater Point-Point(X,Y)) = Public Key In bitcoin, what is the range of that secret can be? What can it be at most and at least? Is there a limit to it like 2^256? If yes what is the logic behind that too?
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