rable from 
backups. Routine systematic failures must not be allowed to accumulate and cause data loss 
beyond the tolerances established by the repository policies. Mechanisms such as checksums 
(MD5 signatures) or digital signatures should be recognized for their effectiveness in 
detecting bit loss and incorporated into the overall approach of the repository for validating 
integrity. 
AUDIT AND CERTIFICATION OF TRUSTWORTHY DIGITAL REPOSITORIES 
CCSDS 652.0-M-1 
Page 5-8 
September 2011 
5.1.1.3.1 The re