The chain of custody is a document or series of documents used to track and record the collection and preservation of evidence. This documentation is used as proof that the evidence was not tampered with (or could not have been tampered with) prior to being shown in legal proceedings or courts.
Chain of custody (CoC), in legal contexts, is the chronological documentation or paper trail that records the sequence of custody, control, transfer, analysis, and disposition of materials, including physical or electronic evidence. Of particular importance in criminal cases, the concept is also applied in civil litigation and more broadly in drug testing of athletes and in supply chain management, e.g. to improve the traceability of food products, or to provide assurances that wood products originate from sustainably managed forests. It is often a tedious process that has been required for evidence to be shown legally in court. Now, however, with new portable technology that allows accurate laboratory quality results from the scene of the crime, the chain of custody is often much shorter which means evidence can be processed for court much faster.
The term is also sometimes used in the fields of history, art history, and archives as a synonym for provenance (meaning the chronology of the ownership, custody or location of a historical object, document or group of documents), which may be an important factor in determining authenticity.