org.dihedron.crypto.operations.sign.pdf.PDFSigner.java Source code

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Here is the source code for org.dihedron.crypto.operations.sign.pdf.PDFSigner.java

Source

/**
 * Copyright (c) 2012-2014, Andrea Funto'. All rights reserved. See LICENSE for details.
 */
package org.dihedron.crypto.operations.sign.pdf;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import java.security.Key;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.cert.Certificate;

import org.dihedron.core.License;
import org.dihedron.core.library.Traits;
import org.dihedron.core.streams.Streams;
import org.dihedron.crypto.Crypto;
import org.dihedron.crypto.KeyRing;
import org.dihedron.crypto.exceptions.CryptoException;
import org.dihedron.crypto.operations.sign.Signer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfSignatureAppearance;
import com.itextpdf.text.pdf.PdfStamper;

/**
 * @author Andrea Funto'
 */
@License
public class PDFSigner extends Signer {

    @License
    public enum Mode {
        /**
         * There can only be one signature of this kind per document.
         */
        EXCLUSIVE,

        /**
         * There can be multiple signatures of this kind per document.
         */
        CONCURRENT;
    }

    /**
     * The logger. 
     */
    private static Logger logger = LoggerFactory.getLogger(PDFSigner.class);

    private Key key = null;

    private Certificate[] chain = null;

    private Mode mode = null;

    public PDFSigner(String alias, KeyRing keyring, Provider provider)
            throws GeneralSecurityException, CryptoException {
        this(alias, keyring, provider, Mode.CONCURRENT);
    }

    /**
     * Constructor.
     * @throws CryptoException 
     * @throws GeneralSecurityException 
     */
    public PDFSigner(String alias, KeyRing keyring, Provider provider, Mode mode)
            throws GeneralSecurityException, CryptoException {
        super(alias, keyring, provider);
        this.mode = mode;

        // retrieve key and certificate
        key = keyring.getPrivateKey(alias);
        //certificate = accessor.getCertificate(alias);      
        chain = keyring.getCertificateChainAsArray(alias);

        logger.trace("PdfSigner initialised");
    }

    @Override
    public byte[] sign(byte[] data) throws CryptoException {
        ByteArrayInputStream input = null;
        ByteArrayOutputStream output = null;
        try {
            input = new ByteArrayInputStream(data);
            output = new ByteArrayOutputStream();
            sign(input, output);
            return output.toByteArray();
        } finally {
            Streams.safelyClose(input);
            Streams.safelyClose(output);
        }

        //      ByteArrayOutputStream baos = new ByteArrayOutputStream();  
        //      
        //      try {
        //         PdfReader reader = new PdfReader(data);
        //         PdfStamper stamper = PdfStamper.createSignature(reader, baos, '\0');
        //         PdfSignatureAppearance appearance = stamper.getSignatureAppearance();
        //         //appearance.setVisibleSignature("mySig");
        //         appearance.setReason("Signed with Dihedron WebSign - Digital Signature for the Web ver. " + CryptoLibrary.valueOf(Traits.VERSION));
        //         appearance.setLocation("Hidden Signature");
        //          
        //         appearance.setCrypto((PrivateKey)key, chain, null, PdfSignatureAppearance.WINCER_SIGNED);
        //         if(mode == Mode.EXCLUSIVE) {
        //            appearance.setCertificationLevel(PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED);
        //         }
        //         // TODO: no graphic signature mode enabled yet
        //   //      if (graphic) {
        //   //         appearance.setAcro6Layers(true);
        //   //         appearance.setSignatureGraphic(Image.getInstance(RESOURCE));
        //   //         appearance.setRenderingMode(
        //   //         PdfSignatureAppearance.RenderingMode.GRAPHIC);
        //   //      }
        //      
        //         stamper.close();
        //      } catch(IOException e) {
        //         throw new CryptoException("I/O exception writing the PDF", e);
        //      } catch (DocumentException e) {
        //         throw new CryptoException("document exception writing the PDF", e);
        //      }
        //      return baos.toByteArray();
    }

    @Override
    public void sign(InputStream input, OutputStream output) throws CryptoException {
        try {
            PdfReader reader = new PdfReader(input);
            PdfStamper stamper = PdfStamper.createSignature(reader, output, '\0');
            PdfSignatureAppearance appearance = stamper.getSignatureAppearance();
            //appearance.setVisibleSignature("mySig");
            appearance.setReason("Signed with Dihedron WebSign - Digital Signature for the Web ver. "
                    + Crypto.valueOf(Traits.VERSION));
            appearance.setLocation("Hidden Signature");

            appearance.setCrypto((PrivateKey) key, chain, null, PdfSignatureAppearance.WINCER_SIGNED);
            if (mode == Mode.EXCLUSIVE) {
                appearance.setCertificationLevel(PdfSignatureAppearance.CERTIFIED_NO_CHANGES_ALLOWED);
            }
            // TODO: no graphic signature mode enabled yet
            //      if (graphic) {
            //         appearance.setAcro6Layers(true);
            //         appearance.setSignatureGraphic(Image.getInstance(RESOURCE));
            //         appearance.setRenderingMode(
            //         PdfSignatureAppearance.RenderingMode.GRAPHIC);
            //      }      
            stamper.close();
        } catch (IOException e) {
            logger.error("I/O exception writing the PDF", e);
            throw new CryptoException("I/O exception writing the PDF", e);
        } catch (DocumentException e) {
            logger.error("invalid document: exception writing the PDF", e);
            throw new CryptoException("document exception writing the PDF", e);
        }
    }
}