Should I pass sensitive data to a Process.Start call in .NET?

Question

I'm working on a .NET Windows application that will use Process.Start to launch another internally developed .NET application running on the same PC. I need to pass database connection information, including a user ID and password, to the target application. I'm trying to determine whether I need to encrypt the information before I send it.

Assuming the end user's PC isn't compromised, will the connection information be exposed anywhere if I pass it unencrypted in the arguments?

Would something like this be OK...

string myExecutable = "myApp.exe";
string server = "myServer";
string database = "top_secret_data";
string userID = "myUser";
string password = "ABC123";
string dbInfo = string.Format("server={0} database={1} userID={2} password={3}", server, database, userID, password);
ProcessStartInfo startInfo = new ProcessStartInfo(myExecutable, dbInfo);
Process.Start(startInfo);

Or should I use something like this...

var crypto = new MySymmetricCryptoLib.Crypto();
string myExecutable = "myApp.exe";
string server = crypto.Encrypt("myServer");
string database = crypto.Encrypt("top_secret_data");
string userID = crypto.Encrypt("myUser");
string password = crypto.Encrypt("ABC123");
string dbInfo = string.Format("server={0} database={1} userID={2} password={3}", server, database, userID, password);
ProcessStartInfo startInfo = new ProcessStartInfo(myExecutable, dbInfo);
Process.Start(startInfo);

Answer 1

Retrieving the arguments that a process was called with is quite easy, so they'll be exposed locally to a technically-minded user. If that's not a problem for you, then I wouldn't worry about it, since you say you're not transmitting over the network and your question asks us to assume the machine's not compromised.

Answer 2

It's not clear from your question from whom you are trying to protect the data. It's confusing because you said "assume the PC is not compromised".

If you are starting a local process on the machine and the machine is not compromised then what is there to protect from? Nothing will traverse the network in this scenario so no one can spy on the arguments.

However, if you're worried about anyone who may have administrative access to the computer or the user potentially seeing the data, then yes you must encrypt it. It's fairly easy to see the command line arguments of a process. Any semi-competent user could find them.