Evidence
Authentication
Definition
Authentication under Federal Rule of Evidence 901 requires the proponent of evidence to produce evidence sufficient to support a finding that the item is what the proponent claims it is. This is a low threshold — the proponent need only make a prima facie showing. Methods of authentication include testimony of a witness with knowledge, expert comparison, distinctive characteristics, voice identification, and the reply letter doctrine. Self-authenticating documents (FRE 902) do not require extrinsic evidence of authenticity.
Example
A party seeks to introduce an email as evidence. Authentication can be established by the testimony of a recipient who recognized the sender's email address and writing style.