Providing online data backup and restore, disaster recovery, and business continuity services

  

Compression, Encryption and Security

How and to what standard is the data encrypted? The small files and delta blocks of data are first compressed and then encrypted with DES, using a 56bit key, which is set by the customer during the installation of the DS-Client Backup Appliance. This key is unknown to DataAssure and the data remains encrypted at all times, even when stored offsite. The backup data is only unencrypted by the DS-Client Backup Appliance at your site when it has retrieved the encrypted data from DataAssure's Data Center for a restore.    What do you mean by compression? What happens? Compression can be likened to letting the air out of a balloon. Although the air has gone, the structure still exists and it can be re-inflated easily. The advantage is that it takes less room. Files, especially databases, are often full of empty space, which can be removed to make the file smaller for transit, whilst making it very easy to recreate.    Is there added compression on already compressed files (e.g. zip files)? Zip files and other compressed files are already efficiently compressed. DASB cannot improve on the compression, but the file will only be transmitted once. If the file should change, then delta blocking will be used to ensure only the changed portions of the file are retransmitted.    What is delta blocking? How does it work? Delta blocking is an advanced logic that divides all files into 4K blocks. When the file is detected to have changed, the Checksum of each 4K block is compared against the last known Checksum for the same block of the same file (stored in the database on the DS-Client Backup Appliance). Any blocks that are different are pulled out to be re-transmitted. These delta blocks will also be compressed and encrypted before transmission.