Java Security

Hi

i am trying to encrypt message using private key (RSA), when i try to get the private key, for the given key spec, I get error (java.security.InvalidKeyException: IOException : algid parse error, not a sequence
)

below is he code snippet, error occurs at line no 4

KeyFactory keyFactory;

keyFactory = KeyFactory.getInstance(RSA);

PKCS8EncodedKeySpec privSpec = new PKCS8EncodedKeySpec(encryptionKeyBytes);

privKey = (RSAPrivateKey) keyFactory.generatePrivate(privSpec);

cf = Cipher.getInstance(RSA);

cf.init(Cipher.ENCRYPT_MODE, privKey);

let me know if i am missing something, the key is provide by 3rd party,

Thanks in advance