1. A method of storing data with an application server that preserves privacy of one or more data fields, the method including: receiving, at a privacy proxy server, data representing a user input with first fields to be stored with an application server and at least one second field determined by the privacy proxy server to be encrypted based upon a rule indicating a type of data to encrypt and then stored by the application server; forwarding the first fields, the second field encrypted, and a second field mark that indicates encryption of the second field to the application server to store; the privacy proxy server querying the application server for a report that includes the second field encrypted and at least one of the first fields that has not been encrypted; receiving from the application server the report comprising the at least one of the first fields in a report format and the second field encrypted with a report format placeholder; decrypting the second field and replacing the report format placeholder with the decrypted second field; and causing display of the report with the decrypted second field.