IPhone : Can i convert .app file into NSData?

I am trying to convert my application.app file into NSData and generating hash value. But i am getting nil. Here is my peace of code and correct me where i am wrong.

Note: Iam bale to get same thing for Info.plist file.

NSString *documentdir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString *appPath = [documentdir stringByAppendingPathComponent:@"application.app"];
NSData *appPathData = [NSData dataWithContentsOfFile:appPath];