Use HSM to digitally sign or certify documents

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 * Copyright 2014 Adobe Systems Incorporated
 * All Rights Reserved.
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 * NOTICE:  All information contained herein is, and remains
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package com.adobe.docassurance.samples;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.jcr.Binary;
import javax.jcr.Node;
import javax.jcr.RepositoryException;
import javax.jcr.Session;

import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.api.resource.ResourceResolver;
import org.apache.sling.jcr.api.SlingRepository;
import org.apache.sling.jcr.resource.JcrResourceResolverFactory;

import com.adobe.aemfd.docmanager.Document;
import com.adobe.fd.docassurance.client.api.DocAssuranceException;
import com.adobe.fd.docassurance.client.api.DocAssuranceService;
import com.adobe.fd.docassurance.client.api.DocAssuranceServiceOperationTypes;
import com.adobe.fd.docassurance.client.api.SignatureOptions;
import com.adobe.fd.signatures.client.types.exceptions.InvalidArgumentException;
import com.adobe.fd.signatures.pdf.inputs.CredentialContext;
import com.adobe.fd.signatures.pdf.inputs.DSSPreferences;
import com.adobe.fd.signatures.pdf.inputs.DSSPreferencesImpl;
import com.adobe.fd.signatures.pdf.inputs.PDFSignatureAppearenceOptions;
import com.adobe.fd.signatures.pdf.inputs.UnlockOptions;
import com.adobe.fd.signatures.pdf.inputs.PDFSignatureAppearenceOptions.PDFSignatureAppearanceType;
import com.adobe.fd.signatures.pdf.inputs.PDFSignatureAppearenceOptions.TextDirection;
import com.adobe.fd.signatures.pki.client.types.common.HashAlgorithm;
import com.adobe.fd.signatures.pki.client.types.common.RevocationCheckStyle;
import com.adobe.fd.signatures.pki.client.types.prefs.CRLPreferences;
import com.adobe.fd.signatures.pki.client.types.prefs.CRLPreferencesImpl;
import com.adobe.fd.signatures.pki.client.types.prefs.GeneralPreferencesImpl;
import com.adobe.fd.signatures.pki.client.types.prefs.PKIPreferences;
import com.adobe.fd.signatures.pki.client.types.prefs.PKIPreferencesImpl;
import com.adobe.fd.signatures.pki.client.types.prefs.PathValidationPreferences;
import com.adobe.fd.signatures.pki.client.types.prefs.PathValidationPreferencesImpl;

/**
 * Digital signatures can be applied to PDF documents to provide a level of security. Digital signatures, like handwritten signatures, provide a means by which signers
 * identify themselves and make statements about a document. The technology used to digitally sign documents helps to ensure that both the signer and recipients are clear
 * about what was signed and confident that the document was not altered since it was signed.
 *
 * PDF documents are signed by means of public-key technology. A signer has two keys: a public key and a private key. The private key is stored in a user's credential that
 * must be available at the time of signing. The public key is stored in the user's certificate that must be available to recipients to validate the signature. Information
 * about revoked certificates is found in certificate revocation lists (CRLs) and Online Certificate Status Protocol (OCSP) responses distributed by Certificate Authorities (CAs).
 * The time of signing can be obtained from a trusted source known as a Timestamping Authority.
 *
 * The following Java code example digitally signs a PDF document that is based on a PDF file.
 * The alias that is specified for the security credential is secure, and revocation checking is performed.
 * Because no CRL or OCSP server information is specified, the server information is obtained from the certificate used to
 * digitally sign the PDF document
 *
 * PreRequisites - Digital certificate for signing the document has to be uploaded on Granite Key Store
 */

@Component
@Service(value=Sign.class)
public class Sign{
 @Reference
 private DocAssuranceService docAssuranceService;

 @Reference
    private SlingRepository slingRepository;

 @Reference
    private JcrResourceResolverFactory jcrResourceResolverFactory ;

 /**
  *
  * @param inputFile - path to the pdf document stored at JCR node
  * @param outputFile - path to the pdf document where the output needs to be stored
  * @throws IOException
  * @throws RepositoryException
  * @throws InvalidArgumentException
  * @throws DocAssuranceException
  */
 public void signExtend(String inputFile, String outputFile, String alias) throws IOException, RepositoryException, InvalidArgumentException, DocAssuranceException{

  Document inDoc = new Document(inputFile);
  Document outDoc = null;

  Session adminSession = null;
        ResourceResolver resourceResolver = null;
        try {

          /** resourceResolver with admin privileges to be passed to SignatureServiceAPI and Reader Extensions
          the resource resolver for signature options has to be corresponding to the user who has the signing certificate in his granite key store
          the resource resolver for signature options has to be corresponding to the user who has the credential for reader extension in his granite key store
          here we are using the same resource resolver
          */
          adminSession = slingRepository.loginAdministrative(null);
             resourceResolver = jcrResourceResolverFactory.getResourceResolver(adminSession);

             //retrieve specifications for each of the services, you may pass null if you do not want to use that service
             //as we do not want encryption in this case, passing null for Encryption Options
             //for encrypted document pass Unlock Options - see the method getUnlockOptions() below
    outDoc = docAssuranceService.secureDocument(inDoc, null, getSignatureOptions(alias,resourceResolver),null,null);
        }
  catch(Exception e){
   e.printStackTrace();
  }
        finally{
            /**
             * always close the PDFDocument object after your processing is done.
             */
            if(inDoc != null){
                inDoc.close();
            }
            if(adminSession != null && adminSession.isLive()){
                if(resourceResolver != null){
                    resourceResolver.close();
                }
                adminSession.logout();
            }
        }

        //flush the output document contents to JCR Node
  flush(outDoc, outputFile);

 }

 /**
  *
  * @param rr resource resolver corresponding to the user with the access to signing credential for the
  * given alias "allcertificatesanypolicytest11ee_new" in this case
  * @return SignatureOptions
  */
 private SignatureOptions getSignatureOptions(String alias, ResourceResolver rr){

  //create an instance of SignatureOptions
  SignatureOptions signatureOptions = SignatureOptions.getInstance();

  //set the operation you want to perform - SIGN/CERTIFY
  signatureOptions.setOperationType(DocAssuranceServiceOperationTypes.SIGN);

  //field to sign
  String fieldName = "Signature1" ;

        //Hash Algo to be used to compute digest the PDF document
        HashAlgorithm algo = HashAlgorithm.SHA384;

        //Reason for signing/certifying
        String reason = "Test Reason";

        //location of the signer
        String location = "Test Location";

        //contact info of the signer
        String contactInfo = "Test Contact";

        //Create a PDFSignatureAppearanceOptions object
        //and show date information
        PDFSignatureAppearenceOptions appOptions = new PDFSignatureAppearenceOptions(
                PDFSignatureAppearanceType.NAME, null, 1.0d, null, true, true,
                true, true, true, true, true, TextDirection.AUTO);

        signatureOptions.setSignatureFieldName(fieldName);
        signatureOptions.setAlgo(algo);
        signatureOptions.setContactInfo(contactInfo);
        signatureOptions.setLocation(location);
        signatureOptions.setSigAppearence(appOptions);
        signatureOptions.setReason(reason);
        signatureOptions.setDssPref(getDSSPreferences(rr));
        signatureOptions.setCredential(new CredentialContext(alias, rr, true));
  return signatureOptions;
 }

 private DSSPreferences getDSSPreferences(ResourceResolver rr){
  //sets the DSS Preferences
        DSSPreferencesImpl prefs = DSSPreferencesImpl.getInstance();
        prefs.setPKIPreferences(getPKIPreferences());
        GeneralPreferencesImpl gp = (GeneralPreferencesImpl) prefs.getPKIPreferences().getGeneralPreferences();
        gp.setDisableCache(true);
        return prefs;
    }

    private PKIPreferences getPKIPreferences(){
     //sets the PKI Preferences
        PKIPreferences pkiPref = new PKIPreferencesImpl();
        pkiPref.setCRLPreferences(getCRLPreferences());
        pkiPref.setPathPreferences(getPathValidationPreferences());
        return pkiPref;
    }

    private CRLPreferences getCRLPreferences(){
        //specifies the CRL Preferences
        CRLPreferencesImpl crlPrefs = new CRLPreferencesImpl();
        crlPrefs.setRevocationCheck(RevocationCheckStyle.CheckIfAvailable);
        crlPrefs.setGoOnline(true);
        return crlPrefs;
    }

    private PathValidationPreferences getPathValidationPreferences(){
     //sets the path validation preferences
        PathValidationPreferencesImpl pathPref = new PathValidationPreferencesImpl();
        pathPref.setDoValidation(false);
        return pathPref;

    }

    /**
     * sets Unlock Options for encrypted PDF
     */
    private UnlockOptions getUnlockOptions(){
        UnlockOptions unlockOptions = new UnlockOptions();
        //sets the Open Password for password encrypted PDF
        unlockOptions.setPassword("OpenPassword");

        //for Certificate Encrypted Document, set the alias of the credential uploaded in the user's key store
        //and corresponding resource resolver

        return unlockOptions;

    }
    /**
     * This method copies the data from {@code Document}, to the specified file at the given resourcePath.
     * @param doc
     * @param resourcePath
     * @throws IOException
     */
    private void flush(Document doc, String resourcePath) throws IOException {
   //extracts the byte data from Document
   byte[] output = doc.getInlineData();
   Binary opBin;
   Session adminSession = null;
      try {
         adminSession = slingRepository.loginAdministrative(null);

         //get access to the specific node
         //here we are assuming that node exists
           Node node = adminSession.getNode(resourcePath);

           //convert byte[] to Binary
           opBin = adminSession.getValueFactory().createBinary((InputStream)new ByteArrayInputStream(output));

           //set the Binary data value to node's jcr:data
           node.getNode("jcr:content").getProperty("jcr:data").setValue(opBin);
      } catch (RepositoryException e) {

      }
      finally{

       if(adminSession != null && adminSession.isLive()){
        try {
      adminSession.save();
      adminSession.logout();
     } catch (RepositoryException e) {

     }

             }
      }

  }
}

/**
  *
  * @param credentialAlias alias of the PKI Credential stored in CQ Key Store or
  * the alias of the HSM Credential configured using HSM Credentials Configuration Service.
  * @param resourceResolver corresponding to the user with the access to the key store and trust store.
  * @param isHSMCredential if the alias is corresponding to HSM Credential.
  */
 public CredentialContext(String credentialAlias, ResourceResolver resourceResolver, boolean isHSMCredential);