widened RSA private key support - relates to github #1528

Author: dghgit

prov/src/main/java/org/bouncycastle/jcajce/provider/asymmetric/rsa/CipherSpi.java

@@ -32,7 +32,6 @@
 import org.bouncycastle.crypto.engines.RSABlindedEngine;
 import org.bouncycastle.crypto.params.ParametersWithRandom;
 import org.bouncycastle.crypto.params.RSAKeyParameters;
-import org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters;
 import org.bouncycastle.crypto.tls.TlsRsaKeyExchange;
 import org.bouncycastle.jcajce.provider.asymmetric.util.BaseCipherSpi;
 import org.bouncycastle.jcajce.provider.util.BadBlockException;
@@ -335,10 +334,11 @@ else if (key instanceof RSAPrivateKey)
             }
             else if (params instanceof TLSRSAPremasterSecretParameterSpec)
             {
-                if (!(param instanceof RSAPrivateCrtKeyParameters))
+                if (!(param instanceof RSAKeyParameters) || !((RSAKeyParameters)param).isPrivate())
                 {
                     throw new InvalidKeyException("RSA private key required for TLS decryption");
                 }
+
                 this.tlsRsaSpec = (TLSRSAPremasterSecretParameterSpec)params;
             }
         }