lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Michael McCandless <>
Subject Re: Lucene Index Encryption
Date Tue, 05 May 2009 08:22:23 GMT
Would you encrypt at the file level?  Ie, the encryption would live
"under" a RandomAccessFile (RAF) and otherwise feel "normal" to

(I think I remember others exploring encryption at the individual term
level, which is interesting but does leak information in that you can
see individual terms & their frequencies).

Lucene needs to be able to ask a RAF opened for writing what it's
current "position" is during indexing, which it then stores away, and
later during searching it needs to ask a RAF opened for reading to
seek back to that position so it can read bytes from there.  Would the
encryption APIs allow this?

If this is possible then couldn't one make a Directory impl that hides
all encryption/decryption "under the hood"?

(Presumably performance will suffer perhaps substantially since every
search will need to decrypt on the fly...).


On Mon, May 4, 2009 at 6:29 PM,  <> wrote:
> I hope to make this a discussion rather than a request for a feature.
> In the database world, secure data is always encrypted in the database.
> Since I am interested in storing data from a database in the index, at
> times I want to encrypt the index when the file is one disk.
> Currently data stored in the Lucene Index is easily accessible to any
> program that wants to access it. You cannot store sensitive data in the
> index without the fear that it will be readable by all the people that
> have access to the system.
> There are two other posts in the mailing list that ask a question about
> Lucene Index Encryption. In both cases, I think that the conservation
> was dropped or the feature put off.
> Basically, I am asking for comments on the topic. I might consider
> coding the feature, but I would only do it if I am sure that the feature
> would be useful and accepted back into the core codebase of Lucene.
> The Sun javax.crypto package is available in the JDK 1.4 so using that
> package could be possible way of providing an encrypted file.
> The other option is Bouncy Castle, which is now being used in the PDFBox
> and Tika projects.
> In any case, because the normal Lucene Index implementation would not
> use an encrypted index, all references to Security classes should load
> dynamically with the "Class.forName()" method if they were not part of a
> standard JRE, to guarantee no additional requirements are placed on
> people currently using the Lucene libraries.
> Then there is the issue of what to use as the Encryption Key, and how to
> allow access to the Index files from the various programs that may need
> to get to the data. The Encryption Key needs to external from any
> program that accesses the Index, because with Java, if the key were
> stored in the code, it would be easily found with a simple decompile of
> the Java class.
> I don't have answers to the questions, but basically I am requesting
> comments on the topic.
> I imagine that if I put Encryption and Decryption at the I/O level,
> immediately before a segment was written or immediately after a segment
> was read, that I would minimize the overall impact of the Lucene
> Library.
> Another area to address is Remote Searching. The Remote Interface would
> need extensions that allow for Encrypted Remote files as well as
> Encrypted communication between the machines.
> However, I am not sure of these assumptions. I don't know how many
> places the segments are read and written. I really do not know how to do
> this currently, but would be willing to give it a try it there was
> enough interest shown in the topic.
> Peter
> ---------------------------------------------------------------------
> To unsubscribe, e-mail:
> For additional commands, e-mail:

To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message