Encrypting data in repository

tim91 — Sat, 06 Jul 2013 09:15:05 GMT

Hi,I hope that this is right place to wrote this post.I extended few classes called ContentServiceImpl, FileContentStore, FileContentReader and FileContentWriter.In my new classes called EnryptedContentReader and EnryptedContentWriter i am grabbing data stream in overrided methods and i encrypt/decr

Re: Encrypting data in repository

hr61369256 — Mon, 08 Jul 2013 09:37:54 GMT

Hi tim91,

I've a couple of questions to your encryption and decryption process: where exactly does the encryption/decryption take place? Do I understand you right, when you extend existing classes on server-side, the encryption/decryption is running on server-side? What about content transmission from server to client and vise versa?

May be that I misunderstood something.

Thanks, Ralf

Re: Encrypting data in repository

tim91 — Wed, 10 Jul 2013 11:15:14 GMT

Thanks for Your reply.

Process of encrypting and decrypting is on server side.
During transmission file to the server content is encrypting in overloaded method called copyStreams with oryginal is stored in class org.alfresco.repo.content.AbstractContentWriter

<java>
@Override
   public int copyStreams(InputStream in, OutputStream out) throws IOException {

      AESManager manager = new AESManager();

      int bytesReaded = manager.encrypt(in, out, encryptionKey.getBytes("UTF-8"));

      return bytesReaded;

   }
</java>

As You can see i am grabbing inputStream and in method encrypt i am encrypting stream and saving it in outputStream.

Problem is as i wrote with downloading file, i am using this code, oryginal method is stored in class org.alfresco.repo.content.filestore.FileContentReader

<java>
@Override
    protected ReadableByteChannel getDirectReadableChannel() throws ContentIOException
    {
        try
        {
            // the file must exist
            if (!file.exists())
            {
                throw new IOException("File does not exist: " + file);
            }
            ReadableByteChannel channel = null;



            if( !decrypt ){
               if (allowRandomAccess)
                {
                    RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r"); // won't create it
                    channel = randomAccessFile.getChannel();
                }
                else
                {
                    InputStream is = new FileInputStream(file);
                    channel = Channels.newChannel(is);
                }
            }
            else{
               AESManager am = new AESManager();
                byte[] c = am.decrypt(file, null, "!qazXsw2!@#$".getBytes());
                ByteArrayInputStream is = new ByteArrayInputStream©;
                channel = Channels.newChannel(is);
            }

            // done
            if (logger.isDebugEnabled())
            {
                logger.debug("Opened read channel to file: \n" +
                        "   file: " + file + "\n" +
                        "   random-access: " + allowRandomAccess);
            }
            return channel;
        }
        catch (Throwable e)
        {
            throw new ContentIOException("Failed to open file channel: " + this, e);
        }
    }
</java>

I tried downloading file using CMIS service and i got error because length of stream was different(decrypting process is decreasing content length), after decryption process size of file is smaller and i am wondering if this isn't reason that this solution doesn't work.
I don't know where grab information about file length and change it.

Maybe now what i am trying to do is more clear.

Regards, Tim91

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Encrypting data in repository

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