How to generate EC keypair with Bouncy Castle

Question

my current project is using the fips resources of BouncyCastle only for encrypten/decryption signing and so on.. the keys are still generated with the usual C# bouncy castle. Now, because that is a waste i want to change the code, but i can't find any documentation on how to do this.

WHat i have so far:

ECDomainParameters s = new ECDomainParameters(...?)
        FipsEC.KeyPairGenerator ecGen = CryptoServicesRegistrar.CreateGenerator(new FipsEC.KeyGenerationParameters(s));

but how do i specify the type of curve, G and n?

thanks in advance if you can help somehow.

Answer 1

I found some examples in BouncyCastle unit tests. Try downloading their code with tests: https://www.bouncycastle.org/csharp/download/bccrypto-csharp-1.8.1-src.zip or find the appropriate source on their web page: https://www.bouncycastle.org/csharp/index.html

Then look for the class with unit test: ECTest

For example they have code like this:

/**
 * key generation test
 */
[Test]
public void TestECDsaKeyGenTest()
{
    SecureRandom random = new SecureRandom();

    BigInteger n = new BigInteger("883423532389192164791648750360308884807550341691627752275345424702807307");

    FpCurve curve = new FpCurve(
        new BigInteger("883423532389192164791648750360308885314476597252960362792450860609699839"), // q
        new BigInteger("7fffffffffffffffffffffff7fffffffffff8000000000007ffffffffffc", 16), // a
        new BigInteger("6b016c3bdcf18941d0d654921475ca71a9db2fb27d1d37796185c2942c0a", 16), // b
        n, BigInteger.One);

    ECDomainParameters parameters = new ECDomainParameters(
        curve,
        curve.DecodePoint(Hex.Decode("020ffa963cdca8816ccc33b8642bedf905c3d358573d3f27fbbd3b3cb9aaaf")), // G
        n);

    ECKeyPairGenerator pGen = new ECKeyPairGenerator();
    ECKeyGenerationParameters genParam = new ECKeyGenerationParameters(
        parameters,
        random);

    pGen.Init(genParam);

    AsymmetricCipherKeyPair pair = pGen.GenerateKeyPair();

    ParametersWithRandom param = new ParametersWithRandom(pair.Private, random);

    ECDsaSigner ecdsa = new ECDsaSigner();

    ecdsa.Init(true, param);

    byte[] message = new BigInteger("968236873715988614170569073515315707566766479517").ToByteArray();
    BigInteger[] sig = ecdsa.GenerateSignature(message);

    ecdsa.Init(false, pair.Public);

    if (!ecdsa.VerifySignature(message, sig[0], sig[1]))
    {
        Fail("signature fails");
    }
}