SignedInfo si = fac.newSignedInfo(fac.newCanonicalizationMethod(CanonicalizationMethod.INCLUSIVE,
(C14NMethodParameterSpec) null),
fac.newSignatureMethod(SignatureMethod.RSA_SHA1, null),
Collections.singletonList(ref));
DOMSignContext dsc = new DOMSignContext(privateKey, document.getDocumentElement());
KeyValue keyValue = keyInfoFactory.newKeyValue(publicKey);
KeyInfo ki = keyInfoFactory.newKeyInfo(Collections.singletonList(keyValue));
XMLSignature signature = fac.newXMLSignature(si, ki);
signature.sign(dsc);
} catch (Exception e) {
Logger.warn("Error while signing an XML document.", e);