text: package org.sandrob.bouncycastle.jce.provider;
  
  import java.security.interfaces.RSAPrivateCrtKey;
  import java.security.interfaces.RSAPrivateKey;
  import java.security.interfaces.RSAPublicKey;
  
  import org.sandrob.bouncycastle.asn1.DERObjectIdentifier;
  import org.sandrob.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
  import org.sandrob.bouncycastle.asn1.x509.X509ObjectIdentifiers;
  import org.sandrob.bouncycastle.crypto.params.RSAKeyParameters;
  import org.sandrob.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters;
  
  /**
   * utility class for converting java.security RSA objects into their
   * org.sandrob.bouncycastle.crypto counterparts.
   */
  class RSAUtil
  {
      static boolean isRsaOid(
          DERObjectIdentifier algOid)
      {
          return algOid.equals(PKCSObjectIdentifiers.rsaEncryption)
              || algOid.equals(X509ObjectIdentifiers.id_ea_rsa)
              || algOid.equals(PKCSObjectIdentifiers.id_RSASSA_PSS)
              || algOid.equals(PKCSObjectIdentifiers.id_RSAES_OAEP);
      }
      
      static RSAKeyParameters generatePublicKeyParameter(
          RSAPublicKey    key)
      {
          return new RSAKeyParameters(false, key.getModulus(), key.getPublicExponent());
  
      }
  
      static RSAKeyParameters generatePrivateKeyParameter(
          RSAPrivateKey    key)
      {
          if (key instanceof RSAPrivateCrtKey)
          {
              RSAPrivateCrtKey    k = (RSAPrivateCrtKey)key;
  
              return new RSAPrivateCrtKeyParameters(k.getModulus(),
                  k.getPublicExponent(), k.getPrivateExponent(),
                  k.getPrimeP(), k.getPrimeQ(), k.getPrimeExponentP(),                            k.getPrimeExponentQ(), k.getCrtCoefficient());
          }
          else
          {
              RSAPrivateKey    k = key;
  
              return new RSAKeyParameters(true, k.getModulus(), k.getPrivateExponent());
          }
      }
  }
  