Hi Everyone,

I've had a problem that has been puzzling me for weeks now.

I've been provided with a file from my client which is suppose to be a
private key (in DER format?) which is in the format privateKey.key. My
aim is to eventually use that key for the symmetric signing of data.

decrypted private key file into a java RSAPrivateKey object which is
eventually used for the signing of data. They way i go about this as
follows:

1. Decrypting of Private Key: I have used OpenSSL for this with the
following command
pkcs8 -inform DER -in PrivateKey.key -out PrivateKeyDecrypted
which results in a file with these contents:

-----BEGIN RSA PRIVATE KEY-----
MIICXgIBAAKBgQDArCo5om1eOPsVVkgG57X0VZI+Y/kqSRRqtOVBGj8rKx38nYjH
...
gBIUpRlCzi6zGAhq3KVosQeqp0TAg9aSREW+Jux6nYJigA==
-----END RSA PRIVATE KEY-----

2. Reading in of Key File to Java RSAPrivateKey object:

PKCS8EncodedKeySpec l_ks  = new
PKCS8EncodedKeySpec(getBytesFromFile(PrivateKeyDecrypted));

KeyFactory l_kf = KeyFactory.getInstance("RSA", "BC");

RSAPrivateKey l_pk = (RSAPrivateKey)l_kf.generatePrivate(l_ks );

 private static byte[] getBytesFromFile(String infile){
   File f = new File(infile) ;
   int sizecontent = ((int) f.length());
   byte[] data = new byte[sizecontent];
   try{
     FileInputStream freader = new FileInputStream(f);
     freader.read(data, 0, sizecontent) ;
     freader.close();
     return data;
   }
   catch(IOException ioe){
     System.out.println(ioe.toString());
     return null;
   }
}

The problem is the
RSAPrivateKey l_pk = (RSAPrivateKey)l_kf.generatePrivate(l_ks ); line
throws the following exception:

java.security.spec.InvalidKeySpecException:
java.lang.ClassCastException: org.bouncycastle.asn1.DERUnknownTag
at
org.bouncycastle.jce.provider.JDKKeyFactory$RSA.engineGeneratePrivate(JDKKeyFactory.java:323)
at java.security.KeyFactory.generatePrivate(KeyFactory.java:237)

I tried changing the keyFactory method to
KeyFactory.getInstance("RSA"); however it simply gave me another
exception:

java.security.spec.InvalidKeySpecException: Unknown key spec.
    at
com.sun.net.ssl.internal.ssl.JS_KeyFactory.engineGeneratePrivate(DashoA6275)
    at
com.sun.net.ssl.internal.ssl.JSA_RSAKeyFactory.engineGeneratePrivate(DashoA6275)

Does anyone have any idea what i am doing wrong???