論數位證據於刑事審判上之審查——以違法證據排除法則為核心

An Examination of Digital Evidence in Criminal Trials

法院審理刑事案件，其過程及目的即在審酌檢察官所提出之證據是否足以認定被告確有檢察官所起訴之犯罪事實，為達成此一目的，刑事訴訟法賦予法官兩個權限：一為判斷哪些證據可以進入審判程序做為認定事實之證據，即證據能力之問題；二則是評價證據證明力之強弱，並終局判斷各證據累積之證明力，是否足以確認被告之犯罪事實。基此，刑事法學經過數百年之進程，發展出如違法證據排除法則、傳聞法則、最佳證據法則、直接審理原則、自由心證原則等證據法與訴訟法上之原則，此等原則，尤其是證據法則，都是針對傳統證據之調查、審查所發展而來。然而，時至今日，由於資訊科技產品的大量使用，使得數位證據大量出現在法院之訴訟審理上，而數位證據具有難以蒐集萃取與保存、無法直接感知與理解、易於複製、竄改及刪除、難以證明完整性、難以建立連結關係等異於傳統證據之特性，導致數位證據從偵查中之取證、保管到審理中之調查，都有如何比照傳統證據處理及是否適用上揭證據法則之問題。
本文以法院審理刑事案件之角度，探討數位證據與刑事審判之關係，並參酌取法國外法制之長，從數位證據違法證據排除法則於數位證據之適用與審查之角度，分析數位證據在我國刑事訴訟上之審查程序與問題，期以供作我國目前司法實務運作及未修法之參考。

The purpose of a hearing in criminal cases is to determine whether the evidence provided by the prosecutor is strong enough to confirm the crime committed by the defendant. The Code of Criminal Procedure thus gives judges two powers. One power enables the judge to decide which evidence can be used to prove the fact in the judicial procedure; it is also known as the admissibility of evidence. The second power allows the judge to determine the strength of the probative force of evidence. In the final award, the probative force accumulated from the different evidence would be used to decide whether the defendant has committed the crime. Criminal law, which has been evolving for hundreds of years, accordingly develops the principles of the procedural law and different evidence laws. The different evidence laws include the exclusionary rule, the hearsay rule, the best evidence rule, the principle of direct hearing, and the principle of discretional evaluation of evidence. These evidence laws are specifically developed to investigate and examine traditional evidence. However, with the considerable use of technological devices nowadays, lots of digital evidence has been brought to lawsuit hearings in the courts. The digital evidence is difficult to collect and preserve, and it is hard to directly perceive and feel the authenticity of evidence through its digital form. It can also be easily modified, duplicated, deleted, and usually insufficient to present the integrity of digital evidence. Digital evidence, which is very different from traditional evidence, presents problems in terms of its collection and monitoring during the investigation process. It then becomes questionable if the digital evidence can also be examined in terms of the previously mentioned evidence laws.
This study discusses how digital evidence relates to criminal justice from the aspect of criminal case hearings. With the consideration of the advantages of legal systems in foreign countries, we analyze the issues that digital evidence presents in the process of criminal prosecution in Taiwan, based on the exclusionary rule in examining digital evidence; the procedures of court investigation. The results of the analysis can be used as implications for the operation of judicature and legal changes.