USB Encryption: USB Safeguard is a free encryption tool for USB flash drives. It can be used to password protect any files that reside on your USB drive. Simply create a password and then drag and drop files from your flash drive into the Window. To gain access the encrypted files, simply re-enter your password.
FreeOTFE is a Free On The Fly Encryption tool that can be used for Portable USB Encryption. The tool can be used to create encrypted volumes, virtual disks or entire partitions using AES, Blowfish, Serpent, Twofish encryption algorithms. Volumes Encrypted by FreeOTFE may be file, partition, or disk based and will remain hidden until mounted and accessed via your password by the tool.
Remora USB Disk Guard is a free portable file encryption tool designed to encrypt files and folders on your USB flash drive or local hard disk. This portable application can be stored and run directly from any flash drive or portable storage device, requiring absolutely no installation.
USB Encryption with TrueCrypt – Portable Data Protection: Need a reliable way to encrypt your sensitive data on USB drives or external storage? This open source disk encryption software that allows you to securely encrypt files and folders on USB flash drives, portable storage devices, and hard disk partitions. Designed for on the go security, TrueCrypt supports traveler mode, meaning it can be launched directly from your USB drive without installation on the host system.