Duplicity!

Duplicati is the only portable backup program, able to send backups in encrypted form to another computer or SkyDrive using one of several methods (WebDAV, FTP, SFTP/SCP/SSH, Amazon S3, Rackspace CloudFiles, USB disk, Windows network share). Time scheduler e.g. for auto-backups every 3rd Monday on 10 a.m.German, Danish, English, French, Portugese. Can also be startet from command-line. Support for snapshots via VSS and LVM: Backup of open files. Duplicati is a rewrite of Duplicity/ftplicity, written for Windows (in managed C# .NET). It also runs on Linux using the Mono framework.The lastest portable version in all 5 languages can be downloaded as a zip file from https://github.com/duplicati/duplicati/releases »

CrashPlan lets you automatically back up your hard drive to another computer. The program offers secure cloud storage, in addition to local backups, and continuous, minute-by-minute backup. All backed-up files are encrypted.

Déjà Dup is a simple backup tool. It hides the complexity of doing backups the 'right way' (encrypted, off-site, and regularly) and uses Duplicity as the backend. It features support for local or remote backup locations, including Amazon S3.

Veeam Endpoint Backup provides a simple solution for backing up Windows-based desktops and laptops. With Veeam Endpoint Backup you can easily back up your PC to an external hard drive, NAS (network-attached storage) share or a Veeam Backup & Replication repository. And if your system crashes, hard drive fails, or a file gets corrupted or accidentally deleted, you can recover what you need in minutes—like it never even happened.

BorgBackup (short: Borg) is a deduplicating backup program. Optionally, it supports compression and authenticated encryption.

rdiff-backup backs up one directory to another, possibly over a network. The target directory ends up a copy of the source directory, but extra reverse diffs are stored in a special subdirectory of that target directory, so you can still recover files lost some time ago. The idea is to combine the best features of a mirror and an incremental backup. rdiff-backup also preserves subdirectories, hard links, dev files, permissions, uid/gid ownership, modification times, extended attributes, acls, and resource forks. Also, rdiff-backup can operate in a bandwidth efficient manner over a pipe, like rsync. Thus you can use rdiff-backup and ssh to securely back a hard drive up to a remote location, and only the differences will be transmitted. Finally, rdiff-backup is easy to use and settings have sensical defaults. »

Duplicacy is a new generation cloud-backup tool supporting 5 major cloud-storage providers (Amazon S3, Google Cloud Storage, Microsoft Azure, Dropbox, and Backblaze), as well as local disks and SFTP servers (such as Mac/Linux computers or NAS boxes). Duplicacy is the only cloud-backup tool that offers all the following 7 essential features:

Very efficient backup system based on the git packfile format, providing fast incremental saves and global deduplication (among and within files, including virtual machine images).

MultiCloudBackup securely back up your personal files offsite using free online storage such as Dropbox, Google Drive, etc.It's like CrashPlan but instead of using and paying their storage, MultiCloudBackup allows you to use your own cloud storage.

Bareos is a 100% open source fork of the backup project Bacula . The fork is in development since late 2010, it has a lot of new features.

Stellar Insta Backup is a Windows data backup software to create full volume backup or backup of selected files and folders. The tool facilitates different types of data backups; such as full backup, differential backup, and incremental backup. To access backup data, you can mount or unmount the backup image. This efficient tool creates identical clone of complete hard drive or any hard drive volume. For the safety of backed up files, the tool creates virus-free ‘Secure Zone’. The bootable Rescue Disk is used to boot the system in any event of OS crash/inaccessibility. »