Why does a bad password cause “Padding is invalid and cannot be removed”?

Question

I needed some simple string encryption, so I wrote the following code (with a great deal of \"inspiration\" from here):

    // create and initialize a crypto         


        

Answer 1

Another reason of the exception might be a race condition between several threads using decryption logic - native implementations of ICryptoTransform are not thread-safe (e.g. SymmetricAlgorithm), so it should be put to exclusive section, e.g. using lock. Please refer here for more details: http://www.make-awesome.com/2011/07/system-security-cryptography-and-thread-safety/