Rsyncrypto

(Page count as of: 20YY-MM-DD wikiFactor as of: 2012-MM-DD)

The Rsyncrypto wiki is a place to discuss Rsyncrypto and related tools and techniques. This Rsyncrypto wiki was, and powered by , but in 2019, the wiki was recreated using the same original URL, but all edit history, and nigh-on all content was lost.

Sometimes it is necessary to store files on a remote server. This is typically needed for backup purposes. When that is done, there are two concerns that need to be addressed, ideally, you want to both: Both problems have rather simple solutions: There is just one problem: the two solutions contradict. Plain mode of files hide the specific changes to the file, making rsync useless at detecting in-file changes. This is where rsyncrypto comes to the rescue.
 * ''Why is Rsyncrypto
 * 1) How to keep the  of the files stored?
 * 2) How to keep bandwidth usage to a minimum?
 * 1) Encrypt the files prior to sending them, keep the key locally.
 * 2) Use rsync to only transfer the changes.

Rsyncrypto is a modified encryption scheme. It is based on industry standard (AES) for symmetric encryption, as well as  (Rivest–Shamir–Adleman) for having different keys for each file while allowing a single key to decrypt all files. It even uses an encryption mode that is based on (CBC).
 * ''What is Rsyncrypto

Rsyncrypto does, however, do one thing differently. It changes the encryption schema from plain CBC to a slightly modified version. This modification ensures that two almost identical files, such as the same file before an after a change, when encrypted using Rsyncrypto and the same key, will produce almost identical encrypted files. This means that both objectives can be achieved simultaneously.

Rsyncrypto won first prize in the 2007 edition  trophy competition (Trophées du Libre) in the  category.
 * ''Awards

There are some tutorials on line, which might help you with your experience with rsyncrypto:
 * ''Tutorial
 * Efficient rsyncrypto hides remote sync data, by Ben Martin on 1 February 2008, Linux.com, via Archive.org
 * https://blog.wuxinan.net/archives/86 — rsyncrypto: rsync + encryption, atppp's Blog, 7 September 2007


 * ''More resources
 * Plans for future versions
 * Details about the rsyncrypto algorithm


 * ''Related wiki
 * Unison Wiki


 * ''External links
 * rsyncrypto repository — at SourceForge.net, via Archive.org