If you ever worry about a bit error happening to your files and not finding out about it, you should use MD5 checksums (or some similar method) to be able to verify that the file has not changed.
The general theory behind a checksum (or “Message Digest” = “MD”) is that it provides a unique 128-bit number for each and every file, based on its content. If one bit changes, the MD5 checksum (sometimes called “hash”) changes. The checksum is repeatable, does not permit discovery of two different files that produce the same checksum, and is non-reversible (i.e. you can’t create the content from the checksum).Common practice in audio archiving is to use 128-bit hashes, although larger hashes are available. The other common practice is to take the entire filename, including extension, and add a second “MD5″ extension to that. The *.*.md5 file contains the MD5 hash plus generally the filename.
An alternate configuration is to create one file named checksums.md5 for the entire folder to save downloading effort.
While there are many options for creating MD5 checksums, originally, for Windows, FastSum was a convenient and low-cost package, but it has not been recently updated and there are some issues with it not shutting down cleanly that led me to stop using it, even though I think they invented the format of the stand-alone file.
While there are many options for creating MD5 hashes, for Windows, as of 2021, I have switched to Md5Checker http://getmd5checker.com/ and it’s free! It is faster to work with and more intuitive. Note if you rename a main file, you need to re-run the hash generation so the updated file name is in the .MD5 file.
At any point in the future, to verify your files, you create a new MD5 hash and compare it to the ones that were created when the file was created. If they match, you know your file has not changed. The likelihood of both the original file and the hash file changing so that they still appear valid is essentially nil.
Some applications, like D-Space, check the integrity of all the files in the system on a regular basis using MD5 hashes.
If you receive WAV files from me, more than likely, you will also receive MD5 hashes in the same package, be that on a DVD, hard drive, or via the Internet.
It only takes a minute to create these and it truly does offer peace of mind.
Note that I changed the usage to use the more correct term “hash” instead of “checksum.”
https://en.wikipedia.org/wiki/MD5
According to the above article, while MD5 is a deprecated cryptographic hash, “It can still be used as a checksum to verify data integrity, but only against unintentional corruption….and may be preferred due to lower computational requirements than more recent…algorithms.” It seems that the media archiving world has been using MD5 hashes for confirming that files have not been corrupted for at least two decades. Changing that embedded base would be difficult.
For more information, see:
https://en.wikipedia.org/wiki/Secure_Hash_Algorithms