Everyone's interests are best served if there are clear rules to follow that strike a fair balance between the legitimate needs of law enforcement and the right of individuals and enterprises to the privacy that is at the heart of the Fourth Amendment. Tamura has provided a workable framework for almost three decades, and might well have sufficed in this case had its teachings been followed. We believe it is useful, therefore, to update Tamura to apply to the daunting realities of electronic searches which will nearly always present the kind of situation that Tamura believed would be rare and exceptional--the inability of government agents to segregate seizable from non-seizable materials at the scene of the search, and thus the necessity to seize far more than is actually authorized.

We accept the reality that such over-seizing is an inherent part of the electronic search process and proceed on the assumption that, when it comes to the seizure of electronic records, this will be far more common than in the days of paper records. This calls for greater vigilance on the part of judicial officers in striking the right balance between the government's interest in law enforcement and the right of individuals to be free from unreasonable searches and seizures. The process of segregating electronic data that is seizable from that which is not must not become a vehicle for the government to gain access to data which it has no probable cause to collect. In general, we adopt Tamura's solution to the problem of necessary over-seizing of evidence: When the government wishes to obtain a warrant to examine a computer hard drive or electronic storage medium in searching for certain incriminating files, or when a search for evidence could result in the seizure of a computer, see, e.g., United States v. Giberson, 527 F.3d 882 (9th Cir. 2008), magistrate judges must be vigilant in observing the guidance we have set out throughout our opinion, which can be summed up as follows:

1. Magistrates should insist that the government waive reliance upon the plain view doctrine in digital evidence cases. See p. 11876 supra.

2. Segregation and redaction must be either done by specialized personnel or an independent third party. See pp. 11880-81 supra. If the segregation is to be done by government computer personnel, it must agree in the warrant application that the computer personnel will not disclose to the investigators any information other than that which is the target of the warrant.

3. Warrants and subpoenas must disclose the actual risks of destruction of information as well as prior efforts to seize that information in other judicial fora. See pp. 11877-78, 11886-87 supra.

4. The government's search protocol must be designed to uncover only the information for which it has probable cause, and only that information may be examined by the case
agents. See pp. 11878, 11880-81 supra.

5. The government must destroy or, if the recipient may lawfully possess it, return non-responsive data, keeping the issuing magistrate informed about when it has done so and what it has kept. See p. 11881-82 supra.

Just as Tamura has served as a guidepost for decades, we trust that the procedures we have outlined above will prove a useful tool for the future. In the end, however, we must rely on the good sense and vigilance of our magistrate judges, who are in the front line of preserving the constitutional freedoms of our citizens while assisting the government in its legitimate efforts to prosecute criminal activity. Nothing we could say would substitute for the sound  judgment that judicial officers must exercise in striking this delicate balance.