TL:DR; CryptBox creates secure Safes, that can be used just like normal drives and which can be filled with your data.
CryptBox creates secure Safes, that can be used just like normal drives and which can be filled with your data. All content of those safes are encrypted. Safes can only be opened if you know the password.
USB Safeguard is a portable software that allows you to protect your private files with a password on your removable drive using the secure AES 256 bits key. Supports USB flash drive, HDD hard drive, SSD, memory card and others.
PenProtect is the best solution to secure data stored in a USB Flash Drive, Pen Drive or Flash Memory. Protection data with Password and AES encryption (256 bit key). PenProtect requires no installation, is a single file in the home folder.
A free, open source, "on-the-fly" transparent disk encryption program. With this software, you can create one or more "virtual memory cards" on your PDA - anything written to which will be automatically, and securely, encrypted before being stored