Add support for encrypted rsa private key

[StefH]

No description provided.

[oudi]

hi @StefH How is it going?

[StefH]

Sorry I don't have the knowledge to continue on this issue.

[oudi]

@StefH I found a solution can encrypt data with private key , http:https://www.bouncycastle.org/csharp/

Here is the code, you can try.

        public static byte[] RSAPrivateEncrypt(System.Security.Cryptography.RSA priRsa, byte[] byteData)
        {
            var keyPair = DotNetUtilities.GetKeyPair(priRsa);
            var c = CipherUtilities.GetCipher("RSA/ECB/PKCS1Padding");
            c.Init(true, keyPair.Private); //init with private key
            var encryptedBytes = c.DoFinal(temp); //encrypt data with private key
            return encryptedBytes;
        }

[nmbro]

@oudi it is not the issue of how to encrypt data with the privatekey - but that the privatekey itself is encrypted.
RSA Privatekeys can be encrypted if so chosen upon creation with Triple DES.

[StefH]

Correct.

What I want to build is that you can provide an encrypted private key in the
Decode and DecodeParameters in the class OpenSSLPrivateKeyDecoder.cs .

For that to work I

1. need to be able to detect if a privateText is encrypted or not.
2. Decrypt the encrypted text using that password. Maybe this method DecodeEncryptedPrivateKey(...) is a start ?

@nmbro Do you more details, and can you maybe create a PR?