ContentsMD5 Digest
An MD5 message digest is a 128-bit "fingerprint" or digital signature, represented by a string of 32 hex digits. Every unique string of text or contents of a file is guaranteed to produce a unique message digest. More importantly, it is virtually impossible to determine the original string or file from the digest. In other words, the MD5 calculation only works in one direction. This makes it extremely useful for storing passwords or validating the integrity of files.
Since there is no way to get from the digest back to the original text or file, it doesn't matter if anyone sees the digest.
Note: MD5 isn't a substitute for secure passwords. Using an insecure password like "sneeze" or "equine" can still leave your application open to so-called "dictionary attacks," where the hacker simply tries the MD5 digest for every word in the dictionary. Be sure to use secure passwords like "sationicat59" or "b$fer@fe!23."
Tip: A good way to defeat dictionary attacks when using user-supplied passwords is to append a non-alphabetic string to all passwords. For example, simply append "$!%" to the end of any password before generating the MD5 digest. This way, even a really bad password like "password" will be relatively safe from dictionary attacks.