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I'd like to use Bouncy Castle to generate the keypair for use with all *coin variants.

Is this the correct implementation to get the correct ECC curve that the *coin variants use?

    Org.BouncyCastle.Crypto.AsymmetricCipherKeyPair GenerateKeys(int keySize)
    {
        var gen = new Org.BouncyCastle.Crypto.Generators.ECKeyPairGenerator();
        var secureRandom = new Org.BouncyCastle.Security.SecureRandom();
        var keyGenParam = new Org.BouncyCastle.Crypto.KeyGenerationParameters(secureRandom, keySize);
        gen.Init(keyGenParam);

        return gen.GenerateKeyPair();
    }
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IIRC, bitcoin uses an ECDSA key that is hashed using RIPEMD-160. For the particulars, you should look at the bitcoin wiki or vanitygen. –  Nick ODell Dec 20 '12 at 1:53
    
@NickODell I ported Base58Check (RIPE160 + Sha256) to .NET / C# and that is passing all tests. All I need help with is the ECDSA curve. I think Bouncy is the only way... –  makerofthings7 Dec 20 '12 at 1:59
    
I just checked, and you are correct about it doing sha256 first. Out of curiosity, what are you making that requires generating keys but can't use bitcoind? –  Nick ODell Dec 20 '12 at 2:32
    
@NickODell I'm afraid I can't announce anything now. I'll have a timeline in Feb. –  makerofthings7 Dec 20 '12 at 2:59
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1 Answer

Below extract should answer your question.

public class ECKeyPair implements Key
{
    private static final SecureRandom secureRandom = new SecureRandom ();
    private static final X9ECParameters curve = SECNamedCurves.getByName ("secp256k1");
    private static final ECDomainParameters domain = new ECDomainParameters (curve.getCurve (), curve.getG (), curve.getN (), curve.getH ());

    private BigInteger priv;
    private byte[] pub;
    private boolean compressed;


    public static ECKeyPair createNew (boolean compressed)
    {
        ECKeyPairGenerator generator = new ECKeyPairGenerator ();
        ECKeyGenerationParameters keygenParams = new ECKeyGenerationParameters (domain, secureRandom);
        generator.init (keygenParams);
        AsymmetricCipherKeyPair keypair = generator.generateKeyPair ();
        ECPrivateKeyParameters privParams = (ECPrivateKeyParameters) keypair.getPrivate ();
        ECPublicKeyParameters pubParams = (ECPublicKeyParameters) keypair.getPublic ();
        ECKeyPair k = new ECKeyPair ();
        k.priv = privParams.getD ();
        k.compressed = compressed;
        if ( compressed )
        {
            ECPoint q = pubParams.getQ ();
            k.pub = new ECPoint.Fp (domain.getCurve (), q.getX (), q.getY (), true).getEncoded ();
        }
        else
        {
            k.pub = pubParams.getQ ().getEncoded ();
        }
        return k;
    }

}

Check out https://github.com/bitsofproof/supernode for more details.

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