try {
KeyFactory rsaFactory = KeyFactory.getInstance("RSA");
// KeyFactory rsaFactory = KeyFactory.getInstance(JCE_RSA);
RSAPublicKeySpec rsaKeyspec =
new RSAPublicKeySpec(this
.getBigIntegerFromChildElement(Constants._TAG_MODULUS, Constants
.SignatureSpecNS), this
.getBigIntegerFromChildElement(Constants
._TAG_EXPONENT, Constants.SignatureSpecNS));
PublicKey pk = rsaFactory.generatePublic(rsaKeyspec);