What steps will reproduce the problem?
unzip the file
1. Open html page "ZipRarFileupload.html" given in zip and run it.
2. Browse any zip file with big size like 500mb.
3. Click on "Calculate CheckSum" button
Note : please refresh the page after calculating checksum and then try for next 
file as the process is running in web worker thread otherwise it will not work

Its calculates MD5 checksum of file , output is correct but its very very slow, 
taking around 30 minutes for processing 1GB file.
"http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/md5.js"


What version of the product are you using? On what operating system?
I am using CryptoJS v3.1.2, Windows7 with IE11.


Description:
As file is large I am breaking it into chunks and then processing it.
Converting to word array and appying MD5 is very very slow.
Please suggest any faster method otherwise it will be useless to use CryptoJs 
in as processing time is in hours for large files.