Law Review Article Published on the Mathematics Underlying e-Discovery: “HASH: The New Bates Stamp”

This is a really good article on hash algorithms by Ralph C. Losey (HASH: The New Bates Stamp) . Originally Published in the Journal of Technology Law & Policy 1 (June 2007) it offers a compelling new concept / solution for tagging and identifying ESI.

Even if you do not consider yourself to be on the "technical" side of eDiscovery, understanding the hash alogrithm or "hash stamp" is fundemental to anyone wanting to understanding how eDiscovery technology works. Not only can the harsh stamp identify all computer documents like the 100-year-old Bates stamp does for paper documents, it can also authenticate them and reveal if there have been any alterations from the original. This would serve to protect the legal profession from the ever-present danger of fraudulent manipulation of the ephemeral bits and bytes that now make up electronic evidence.

The authentication properties of hash have long been known and used in e-discovery, but there was a serious problem with also using hash as a naming protocol: hash values are way too long.

The two most common kinds of hash are called MD5 and SHA-1. An MD5 hash is 32 alphanumeric values, and the SHA-1 has 40 places. Here is an example of the shorter MD-5 hash: 5F0266C4C326B9A1EF9E39CB78C352DC

For all practical purposes, either of these numbers are too long for normal humans to use to identify an electronic document. For that reason, hash was deemed impractical for use as a document naming protocol, even though it had tremendous advantages in authenticity control.

This where Ralph, the author is this article, got the got the “big idea” last September to truncate the hash values and just use the first and last three places. Under that system the above hash becomes the much more manageable: 5F0.2DC

As explained further in the Article, the six place identification alone avoids collisions 98.6% of the time. In the rare event they match, the full hash values can be consulted. Ralph, who I beleive understates his technical capabilities and insight, gives credit to computer expert, Bill Speros, an attorney consulting in litigation technology and data management, for doing the statistical study to confirm his theory.

So, if you are at all interested in keeping up with eDiscovery technology, this article is well worth reading.