protected void engineinitsign(privatekey privatekey) throws invalidkeyexception {
cipherparameters param = rsautil.generateprivatekeyparameter((rsaprivatekey) privatekey);
signer.init(true, param);
}
protected void engineinitverify(publickey publickey) throws invalidkeyexception {
cipherparameters param = rsautil.generatepublickeyparameter((rsapublickey) publickey);
signer.init(false, param);
}