  Synchronization codes are frequently used in numerical data transmission and
storage. Compression by Substring Enumeration (CSE) is a new lossless
compression scheme that has turned into a new and unusual application for
synchronization codes. CSE is an inherently bit-oriented technique. However,
since the usual benchmark files are all byte-oriented, CSE incurred a penalty
due to a problem called phase unawareness. Subsequent work showed that
inserting a synchronization code inside the data before compressing it improves
the compression performance. In this paper, we present two constraint models
that compute the shortest synchronization codes, i.e. those that add the fewest
synchronization bits to the original data. We find synchronization codes for
blocks of up to 64 bits.
