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  • Cashing Out on “Cache” Files

    Earlier this month, we wrote about how a plaintiff sought certain “cache” files from a third-party. After reading the article once it was published, I realized that we referred to “cache” files as if all legal professionals would understand the concept. For those of you who did not Google “what is a cache file,” here is some general information about them and how they can be used during litigation.

    During discovery parties often focus on “tangible” data that exists on physical storage devices, such as e-mail messages, documents, pictures, music, video, or application software data.  As litigants become more knowledgeable about computers, however, the data they request during discovery may include items that are not so tangible, such as “cached” data.  Since cache is electronically stored information, it should be evaluated as potentially discoverable data.  So, what exactly is cache?

    Clearwell’s E-Discovery Glossary defines cache as, “a dedicated, high speed storage location that can be used for the temporary storage of frequently used data. As data may be retrieved more quickly from cache than the original storage location, cache allows applications to run more quickly. Web site contents often reside in cached storage locations on a hard drive.” See “Cache,” Clearwell E-Discovery Glossary.  Cache files are generated for multiple purposes. For example, when a programmer wants to speed up their software because the data takes too long to recreate or once the data is created it doesn’t change too often, the programmer may write the software to store some of the data in your computer’s local memory, the Random Access Memory (RAM).  The files stored in the RAM are considered temporary “cached” files.

    Similarly, all web browsers have a place to store cache.  A web browser’s cache is where the browser stores pieces of a particular website in order to display it more quickly when re-visiting that site. Typically, a web browser’s cache reduces the amount of information that has to be transmitted from a website’s server, as the information previously stored in the cache can be accessed by the browser without having to download the data for a second time.  By storing the data locally, the amount of bandwidth and compute cycles used by the server’s CPU is reduced. This helps to improve the responsiveness of a particular action on a website, and makes the site more quickly navigable.

    Whether a duty to preserve or a litigation hold includes cache files will depend greatly on the context of the case.  For example, last year in People v. Kent, 2010 N.Y. App. Div. LEXIS 7405 (App. Div. 2d Dept. Oct. 12, 2010) the Appellate Court allowed the use of  temporary files automatically “cached” by an internet browser to serve as evidence of promoting and possessing child pornography during a defendant’s prosecution.  There, the court reasoned that “the mere existence of an image automatically stored in the cache, standing alone, is legally insufficient to prove either procurement or knowing possession of child pornography.”  The fact that there was stored cache of multiple websites relating to child pornography, however, established a pattern of the defendant’s Internet browsing, and “[t]he evidence in totality was legally sufficient” to convict the defendant.

    The cache used during the prosecution of Kent goes to show that courts are gradually including more technical aspects of ESI.  As these files become more important to the litigation and are requested more often during the discovery process, it is essential to take the steps necessary to preserve or include this particular data in your data retention policy.

    A special thanks to Sean Gajewski for helping with this post.  Sean is a third-year law student at Hofstra University School of Law.  You can reach him by email at srgajewski [at] gmail dot com. Bio: www.sgajewski.com.