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From David Dundua <da...@dundua.com>
Subject XMLCiphter.encryptData fails when data is less then 17 bytes in length
Date Thu, 26 Jul 2007 15:33:03 GMT
Following demonstrates a NPE being thrown when data is less then 17 bytes in
length.  Is this a known issue?  Any thoughts on this would be appreciated.

Thanks

---------------------------------

package gov.epa.cdx.xml.security;

import org.apache.xml.security.encryption.EncryptedData;
import org.apache.xml.security.encryption.EncryptedKey;
import org.apache.xml.security.encryption.XMLCipher;
import org.apache.xml.security.keys.KeyInfo;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javax.crypto.KeyGenerator;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.security.*;
import java.io.ByteArrayInputStream;

/**
 * @author David Dundua (david@dundua.com)
 * @version $Id: $
 */
public class SmallDocSizeBug {

    static {
        Security.addProvider(new
org.bouncycastle.jce.provider.BouncyCastleProvider());
        org.apache.xml.security.Init.init();
    }

    private static KeyPair generateRSA() throws Exception {
        //now asymentric key pair
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA");
        kpGen.initialize(1024, new SecureRandom());
        return kpGen.generateKeyPair();
    }

    private static Key generateAES() throws Exception {
        //Create symteric key
        KeyGenerator kg = KeyGenerator.getInstance("AES");
        kg.init(128);
        return kg.generateKey();
    }

    private static Document createEmptyDoc() throws Exception {
        DocumentBuilder builder =
DocumentBuilderFactory.newInstance().newDocumentBuilder();
        return builder.newDocument();
    }

    private static byte[] createDoc(int size) {
        byte[] doc = new byte[size];
        for (int i = 0; i < doc.length; i++) {
            doc[i] = 111;
        }
        return doc;
    }

    public static void main(String[] args) {

        try {
            KeyPair rsaPair = generateRSA();
            Key aesKey = generateAES();
            Document document = createEmptyDoc();
            byte[] doc16Bytes = createDoc(17);

            XMLCipher keyCipher = XMLCipher.getInstance(XMLCipher.RSA_v1dot5);
            keyCipher.init(XMLCipher.WRAP_MODE, rsaPair.getPublic());


            EncryptedKey encryptedKey = keyCipher.encryptKey(document, aesKey);

            //now we going to encrypt stuff
            XMLCipher xmlCipher = XMLCipher.getInstance(XMLCipher.AES_128);
            xmlCipher.init(XMLCipher.ENCRYPT_MODE, aesKey);

            /*
            * Setting keyinfo inside the encrypted data being prepared.
            */
            EncryptedData encryptedData = xmlCipher.getEncryptedData();
            org.apache.xml.security.keys.KeyInfo keyInfo = new KeyInfo(document);
            keyInfo.add(encryptedKey);
            keyInfo.addKeyName("bob@example.com");
            encryptedData.setKeyInfo(keyInfo);


            //Following call fails if the data is less then 17 bytes in length.
            EncryptedData encData = xmlCipher.encryptData(document,
"http://localhost/test",
                    new ByteArrayInputStream(doc16Bytes));

            Element el = xmlCipher.martial(encData);
            document.appendChild(el);


        } catch (Throwable ex) {
            ex.printStackTrace();
        }
    }
}



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