Existing data not encrypted when field is selected for encryption

I have implemented Encrypt module in our site to make the fields encrypted while storing into the database. After installation of this module the new contents added are properly encrypted into the database and while editing the contents all the fields are showing. But our site had some more amount of data prior installing the encrypt module. Now those contents are not showing any data on edit panel. So, please tell me how can I encrypt those old contents in our site.