Generating keyPair using Bouncy Castle

Question

I have Java code for generating keypair using BC as follows:

KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
keyGen.initialize(1024);
KeyPair key = keyGen.generateKeyPair();
PrivateKey priv = key.getPrivate();
PublicKey pub = key.getPublic();
String privateKey = new String(Base64.encode(priv.getEncoded(), 0,priv.getEncoded().length, Base64.NO_WRAP));
String publicKey1 = new String(Base64.encode(pub.getEncoded(), 0,pub.getEncoded().length, Base64.NO_WRAP));
String publicKey = new String(Base64.encode(publicKey1.getBytes(),0, publicKey1.getBytes().length, Base64.NO_WRAP));

Now I want to do same in C# using BC. I have downloaded WP8BouncyCastle library via nuget package manager. I have written as:

var kpgen = new RsaKeyPairGenerator();

kpgen.Init(new KeyGenerationParameters(new SecureRandom(new CryptoApiRandomGenerator()), 1024));

var keyPair = kpgen.GenerateKeyPair();
AsymmetricKeyParameter privateKey = keyPair.Private;
AsymmetricKeyParameter publicKey = keyPair.Public;


string prvKey = Convert.ToBase64String(UTF8Encoding.UTF8.GetBytes(privateKey.ToString()));
string pubKey = Convert.ToBase64String(UTF8Encoding.UTF8.GetBytes(publicKey.ToString()));
string pubKey1 = Convert.ToBase64String(UTF8Encoding.UTF8.GetBytes(pubKey.ToString()));

But I need getEncoded() method available in Java which is not available in BC library in C#. This getEncoded() method is used to convert given key into X.509 encoded key.In case of Java, public key getting twice converted (getencoded() and getBytes()) ,I am not able to do same in C#.

Is there any solution to it?

Answer 1

Use the following code for private key:

PrivateKeyInfo pkInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(keyPair.Private);
String privateKey = Convert.ToBase64String(pkInfo.GetDerEncoded());

and following for public:

SubjectPublicKeyInfo info = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public);
String publicKey = Convert.ToBase64String(info.GetDerEncoded());