WSE: Compression, Security and Performance

We have been doing a lot of WSE testing at work while developing our new integration infrastructure. As a part of this project we have built a filter for message level compression in WSE.

One of the interesting things we found out while performance testing the solution was the speed increase resulting from message compression. The system we are building transfers sensitive data across the internet and we are using X509 certificates for integrity and confidentiality. Naturally, we had to apply the compression before the security mechanisms were invoked, as compressing encrypted data isn’t efficient at all. However compressing xml data is very efficient; often resulting in 80% smaller message bodies.

Having a smaller message body means that the encryption and signing process has a lot less data to deal with, and this reduced the processing time significantly. We did of course consider that the smaller payload would increase transfer performance, but on our test-setup this was not a issue.

The bottom line is that our initial testing shows that the gzip compression algorithm is faster than the encryption and signing process used by WSE. This came as a surprise to us as signing involves hashing and the encryption implementation uses a block cipher, and neither of these should have performance issues with large amounts of data; at least not compared to a compression algorithm!

This topic requires a bit more research before I can reach a conclusion, but so far I am a bit surprised. On the other hand, the results we are seeing could be related to some other part of the process like the normalization algorithm.

Having fun ;)