Safe Calculator is a free portable utility that appears to be the plain old Windows calculator, but actually is a very discreet safe allowing you to move your IDs, passwords etc. without fear of consequences in case of loss or theft. After entering your PIN, it will encrypt the file you have chosen. You can takey it with you on your USB flash drive.
Enter your PIN in memory (key [MS]), the calculator goes into safe mode. Browse the directory and select a file, it stores it encrypted in its own executable file. Erasing memory (key [MC]) delivers the standard calculator mode.