Is there any way to protect my code during development so that if a developer leaves my company they are unable to access files in my project?
This is especially important with TFS where the project is downloaded locally, cached, and available for offline use. Ideally the code would be unreadable if they did not have a valid Active Directory user ID.
Even if this idea is not possible, I'd like to learn of any practical deterrent you can think of...
All things considered... no (especially if the project is stored locally as you mentioned). If a developer has access to source code, they have the ability to steal source code. IANAL, but to deter this sort of thing, you need a lawyer to draft up a non-disclosure agreement (NDA) and get your developers to sign it.
From Wikipedia, an NDA is:
a legal contract between at least two parties that outlines confidential material, knowledge, or information that the parties wish to share with one another for certain purposes, but wish to restrict access to by third parties. It is a contract through which the parties agree not to disclose information covered by the agreement.
Assuming they can read the code and compile it while they are there, there's not a lot you can do (unless you ban USB sticks, CR writers, scan all their email etc, and even then they'd find a way of defeating that).
Cover it in the employment contract, make it clear that if the code turns up there will be legal action.
(I've had this happen to me in a past life - an employee did take the code with him. We knew due to an error he made in doing it, and we sent a letter from our laywers pointing out the consequences of him revealing the code to anyone else. It seemed to work)
You can somewhat reduce the risk of code theft if your application is cleanly built into components/modules/plug-ins. The dev would only be given code access to the components that they work on, and compiled code for the rest of the application. I am, of-course, assuming that it's only worthwhile to steal the application as a whole and not just a handful of components.
On the other hand, you would be surprised that code itself is not always as valuable as you would like to think. If there is no sensitive IP in the code that can be directly resold, then is your dev going to just recompile and go head-to-head with you with their own application?
Simon @ http://LabSlice.com Virtual Lab Environments.
You have to extend some form of trust to your developers. If you can't trust them not to take source code with them, how can you trust them not to build back doors and the like into your systems?
Moreover, if they're going to work on code, they're going to need access to it, and if they get access to it they can almost certainly copy it. You can try to limit it, but it's you trying to outthink in advance a group of people who only need to find one mistake you made. Besides, overtly distrusting your developers isn't going to help you anyway.
Are there actual trade secrets built into your code? If so, you might want to rethink that. If not, how much harm will it do in somebody else's possession? They can't legally use it, and the developers that leave will often be able to write something similar anyway.
For this, you want legal protection, not technical.
If you are afraid of losing a code as a whole (rather than the employee copy-paste part of it)...
With your source code management system (you have one, right ?), you can probably have some hooks so that when the user gets the code, part of it is a binary file that is dedicated to only that user and is necessary for the code to compile correctly and run correctly... if you push to the extreme, that will mean having the right hardware system (TPM, hardware keys...etc).
So after you have dealt with all the paperwork as Paul suggests for example, if ever the code leaks anywhere, you can track who is at fault (and knowing that would probably deter anybody to actually even try)
There are ways to secure your entire development environment so that so programmers can keep or take souvenirs of what they are working on. Take a look at www.chaperon-secure.net for possible solutions from secure development environment to vaulted source code repositories.
This really isn't an crypto question. But there is an answer.
1)You should limit developers and only give them access to source that they need to get the job done. This the security principal of "least privilege access". Store binaries of libraries or the executeables in source control if need be.
2)Force all developers to sign a Non-Disclosure contract. Higher developers that you can sue. For instant defending this contract in India is more difficult than defending it in Indiana.