GnuPG for Windows
replacement for the standard windows explorer.
WinSCP is a free SFTP, SCP, S3, WebDAV, and FTP client for Windows.
Container software to encrypt files.
a free cross platform checksum utility, supports 58+ hash algorithms
Shell extension for easily calculating a file's hash (MD5/SHA1/etc.)
MVRT is a small utility to unhide all files and help in virus deletion
A free "on-the-fly" transparent disk encryption program for PC & PDAs.