There are several solutions that make use of these asymmetrical keys. (Asymmetrical keys encrypt in both ways.) The operator can decrypt the file and -if need be- encrypt a file that only an administrator can access. The administrator can then encrypt files, but he won't be able to decrypt them again, unless he has an operator key.

Basically, the administrator has one key and the operator has the other. In your case, you could use any dual-key encryption method. What might be 'best' for me might be pure overkill for your project. It basically depends on the sensitivity of the data you're trying to protect and the number of people who might access this data. Truthfully, there is no 'best' technique. I strongly recommend you use some of the existing implementations and not start to do your own, since creating a secure working crypto algo is very very difficult. Torry's pages also has a long list of components: Īs for ready made stuff for Delphi there are a few good packages available: This is generally referred to as the 'Key Distribution' problem.Ī good place to start reading about crypto is. It all depends on your needs and possibilities to affect application distribution etc.Īn example of a potentially problematic situation is that in your scenario the decryption 'key' needs to be distributed with the application(s) and might make it insecure. There are a multitude of different approaches/algorithms to choose from, and no single algorithm/method can be said to be the best one. A golden rule when doing crypto is to understand that cryptography as a whole it is very difficult.

Decrypt file delphi