Much commercial and free software enables you to encrypt files in an end-user workstation or mobile device. The following are a few examples of free solutions:
GPG: GPG also enables you to encrypt files and folders on a Windows, Mac, or Linux system. GPG is free.
The built-in MAC OS X Disk Utility: Disk Utility enables you to create secure disk images by encrypting files with AES 128-bit or AES 256-bit encryption.
TrueCrypt: A free encryption tool for Windows, Mac, and Linux systems.
AxCrypt: A free Windows-only file encryption tool.
BitLocker: Full disk encryption feature included in several Windows operating systems.
Many Linux distributions such as Ubuntu: Allow you to encrypt the home directory of a user with built-in utilities.
MAC OS X FileVault: Supports full disk encryption on Mac OS X systems.
The following are a few examples of commercial file encryption software:
Symantec Endpoint Encryption
PGP Whole Disk Encryption
McAfee Endpoint Encryption (SafeBoot)
Trend Micro Endpoint Encryption