Tuesday, May 31, 2005


There's a debate afoot about the meaning of a recent Minnesota Court of Appeals opinion ruling that the fact that a defendant in a child porn case had a copy of PGP on his computer was relevant to the charges against him.

More than a few people expressed shock that having or using encryption could be a sign of criminal intent (including Bruce Schneier, while others (including [Update: Orin Kerr on The Volokh Conspiracy] said that the opinion was more narrow than that.

Here's my read of the case.

The trial court stated on the record that the physical evidence presented was not sufficient to support a conviction. This is because no photos were found on the defendant's computer.

The judge then looked to additional evidence, including, most importantly, the testimony of the victim, evidence "that an encrypting capability was employed by the Defendant” and evidence that “occasions [] indicate that there was advance notice of that so called surprising and thorough search warrant” executed at appellant’s home. I'm not sure to what this last finding refers, but I think the court may mean that the defendant's searching of the penal code prohibition against child pornography and perhaps other evidence shows he expected police intervention.

This could be relevant for two reasons. The first is that it suggests a consciousness of guilt. Why research the law or have encryption software if you aren't doing anything wrong? This is the disfavored interpretation that people are worried about. The second is that the encryption and expectation of police raids suggests that the defendant must have gotten rid of the incriminating pictures. This is the interpretation Volokh puts forward.

The opinion isn't clear on which inference the trial court drew from the PGP evidence. It says that the trial court cited the victim's testimony that defendant took lewd photos of her with a digital camera as the most important evidence, and then said that the defendant's computer knowledge and skills corroborated her testimony. The appellate court then agrees that the PGP evidence was relevant and refused to second guess the trial court's assessment of the credibility of the victim which was influenced by the PGP evidence.

The opinion is not explicit that the PGP evidence was used to show criminal intent or consciousness of guilt, but I think that is fairly implied, especially since the court is not clear or specific about the relevance of the PGP evidence to the problem of the missing child porn photos. Police did not find encrypted files on the defendant's machine, or evidence that the illegal pictures were encrypted or erased. The opinion references the defendant's "encrypting capability" in the context of other evidence he expected the police to raid him, which could be read either as consciousness of guilt, or as reasn to believe he disposed of the photos. And the victim's testimony that defendant took digital photos of her is not corroborated by the encryption technology in the strict sens of that word. So there is reason to believe that the court drew a broad negative inference from the mere presence of encryption technologies, and this is the reason for concern.

Perhaps more worrisome isn't what this opinion says or doesn't say, but how it could be used by courts looking at this issue in the future. This is why its important for appellate courts to be more explicit about exactly what they are ruling.

Jennifer | 4:09 PM