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How are public & private keys in an address created?

I am scanning in a private key from a QR code in an app I am writting to handle the import of physical bitcoins.

Given a private key, how can I get the public key so that I can lookup its value on the block explorer?

  • Do you want the algorithms? Do you want code in a specific language? Commented Oct 28, 2011 at 21:15
  • Yep, that question answered it.
    – RobKohr
    Commented Oct 29, 2011 at 21:57
  • @RobKohr I made a practical example here: bitcoin.stackexchange.com/a/29811/1761 I hope this help you.
    – Felipe
    Commented Jul 31, 2014 at 21:01

1 Answer 1


In ECDSA public keys are usually generated from a random private key. The simple answer then would be, that instead of using a random private key, you use the given private key and it should generate the public key. After that, perform the steps listed in the Wiki to find out the conventional notation for the public key you can use anywhere.

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