Security.Cryptography.RSACryptoServiceProvider.Decrypt - cannot access a disposed object

Question

Our company has a web program to decrypt an encrypted string. The program works fine if not many requests calling it. If not (say over 150 requests at the same time) it runs into one of the following situations: 1) System.Security.Cryptography.RSACryptoServiceProvider.ImportParameters(RSAParameters parameters) at System.Security.Cryptography.RSA.FromXmlString(String xmlString) at ....... Cannot access a disposed object or 2) System.Security.Cryptography.RSACryptoServiceProvider.Decrypt(Byte[] rgbBoolean fOAEP) at ...... Cannot access a disposed object I appreciate if anyone could point me to the right direction. Arch

shimtanny · Answer

Hi I think you have an instance of RSACryptoServiceProvider in your code. I think this one is the guy who throws the exception. So try to find out if this instance will be accessed even it's already disposed. You can get more informations with the stacktrace and exception informations. Simon

archlee · Answer

Simon I double checked the program. There is no other place will access the security object again. I still could not figure what went wrong so far. Thanks for your continuing input. Arch

shimtanny · Answer

Hi After you have called security.Dispose() you never access the security object? Simon

archlee · Answer

Simon I have also added a lock on the decryption process to control multiple threading. The snippet code is as follows: lock (this) { EncryptDecrypt security = new EncryptDecrypt(Key.xml); String pwd = security.decrypt(encryptString); security.Dispose(); : : } It still returns the same error msg. The program is run by each web request and no other remoting involved as far as I can see. Have I missed something else? Arch

shimtanny · Answer

Hi It must be the other way round. Someone (maybe garbage collection) has called already Dispose() and the you are trying to access this object (which fails). Is there some remoting involved? Or Multithreading? Simon

archlee · Answer

Simon Thanks for your advice. I added the Dispose() in the program and ran the load testing tool and returned the same error msg - Cannot access the disposed object. Any idea. Arch

shimtanny · Answer

Hi Objects that are using external resources (like file handles network connections etc.) are implementing the IDisposable interface. This interface containes a method Dispose(). Calling this method releases the external resources and marks the object as disposed. If you wannt to use a disposed object the exception above will be thrown. So Dispose() will be called either explicit by the garbage collector via the finalizer/destructor or by the keyword using. Maybe this explanation gives you a hint. Simon