DualBackup

DualBackup is a free backup software that allows you to encrypt and back up your files to external hard drive, network drive, thumb drive, CD or DVD.

At the first backup session, all files are backed up. After that, only new files or changed files are backed up. In the incremental backup, only changed blocks of a file is copied to backup destinations. All your files are encrypted with your private key using 256-bit Advanced Encryption Standard (AES) before being copied to backup storage.