Title: Calculate public key from private Post by: JPage on August 03, 2014, 10:11:08 PM I am not so sure about this ECSDA stuff. But I do know it is a bit difficult to calculate the private key from a public key. :)
However, I understand the other way around is quite easy. Does anyone have a formula for that? How do I calculate the public key when I am already in possession of the private key? Title: Re: Calculate public key from private Post by: micaman on August 03, 2014, 10:54:04 PM Check this topic:
https://bitcointalk.org/index.php?topic=78132.0 I believe it's the same question. Title: Re: Calculate public key from private Post by: rz20 on August 03, 2014, 11:39:17 PM In bitaddress you have all the tools to make it https://www.bitaddress.org/
Title: Re: Calculate public key from private Post by: TimS on August 04, 2014, 12:23:52 AM In mathematical terms: pubKey = privKey * G, where G is a specific base point on the elliptic curve (https://en.bitcoin.it/wiki/Secp256k1) y^2 = x^3 + 7 mod (2^256 - 2^32 - 977) (privKey is a number, G and pubKey are points on the curve)
In programmatic terms (the C# one is about as simple as it goes, for self-contained solutions): http://bitcoin.stackexchange.com/a/25039/12034 If you just want an easy, do-it-for-me sort of thing, enter your private key at https://brainwallet.github.io/ Title: Re: Calculate public key from private Post by: R2D221 on August 04, 2014, 02:34:33 AM If you just want an easy, do-it-for-me sort of thing, enter your private key at https://brainwallet.github.io/ You should NEVER enter you private key in any website. If you want to use it, you should download it and run it locally first.Title: Re: Calculate public key from private Post by: bigasic on August 04, 2014, 02:02:44 PM Im not sure how this secure is, but I get a computer that I never use for bitcoin purposes, go to bitaddress.org then disconnect my internet connection and then do the random thing, then print out X amount of public and private keys that is directly connected to my printer. I think thats about as secure as im going to get.
Title: Re: Calculate public key from private Post by: JPage on August 04, 2014, 05:50:59 PM In mathematical terms: pubKey = privKey * G, where G is a specific base point on the elliptic curve (https://en.bitcoin.it/wiki/Secp256k1) y^2 = x^3 + 7 mod (2^256 - 2^32 - 977) (privKey is a number, G and pubKey are points on the curve) In programmatic terms (the C# one is about as simple as it goes, for self-contained solutions): http://bitcoin.stackexchange.com/a/25039/12034 If you just want an easy, do-it-for-me sort of thing, enter your private key at https://brainwallet.github.io/ Thanks TimS - you are awesome. That's what I wanted. Title: Re: Calculate public key from private Post by: tianshiqmdvb147 on August 05, 2014, 03:20:40 AM Check this topic: What?what said?https://bitcointalk.org/index.php?topic=78132.0 I believe it's the same question. Title: Re: Calculate public key from private Post by: bigasic on August 05, 2014, 04:22:57 AM i hope the guy that used this address 1Q7f2rL2irjpvsKVys5W2cmKJYss82rNCy doesn't use it anymore.. the passphrase for the private key, etc is satoshi nakamoto, lol...... I wonder how many easy addresses were made.. this is just another great reason to make sure its fucking secure...
Title: Re: Calculate public key from private Post by: ForgottenPassword on August 05, 2014, 04:32:01 AM i hope the guy that used this address 1Q7f2rL2irjpvsKVys5W2cmKJYss82rNCy doesn't use it anymore.. the passphrase for the private key, etc is satoshi nakamoto, lol...... I wonder how many easy addresses were made.. this is just another great reason to make sure its fucking secure... There are a couple of bots that are "mining" brain wallets. They're using common password dictionaries to generate thousands of brainwallets and emptying any funds. Here is the address of one of them: https://blockchain.info/address/1brain7kAZxPagLt2HRLxqyc3VgGSa1GR Currently 12.4BTC profit for the owner. Apparently some unlucky guy accidentally sent 10BTC to the address "correct horse battery staple" (default on some brainwallet sites): https://blockchain.info/tx/31ff3dc5a0b490e0dc709a27fc50b1dc9c6d17a82b7bae36244293464352fb38 It was taken by the 1brain bot. Title: Re: Calculate public key from private Post by: amaclin on August 05, 2014, 07:04:43 AM the passphrase for the private key, etc is satoshi nakamoto, lol...... I wonder how many easy addresses were made. [offtopic] Do not wonder. You can calc them yourself. About 18k are already seen in the blockchain. Read this reddit article http://www.reddit.com/r/Bitcoin/comments/1zti1p/17956_hacked_brainwallet_passwords/ and visit http://chbs.esy.es [/offtopic] Answering the subject question. Here is my code for Qt/C++/openssl (rewritten from original bitcoin-qt) Code: static EC_KEY* EC_KEY_regenerate_key ( const quint8* priv ) |