Checking if file is tampered after encryption
Posted on 2007-12-04
I am using VB.NEt for a desktop app. Now I have a feature that will export the data into a text file which will be later encrypted. This encrypted file will be copied by the user on a drive and transferred to another PC. Here we will decrypt the file and import the data.
Now my question is: what if the encrypted file is opened by the user and changes made? Due to this, the import routine will get some junk data. Hence I want that after the file is encrypted, we want to take the CRC check and then before importing we again check the CRC to ensure that file is not tampered. How do we accomplish this in VB.NET? Alternately is there any other better way to ensure that file is tampered?