What’s the testimonial of passwords?
In this case described by Orin Kerr, the judge asks if entering a password has any testimonial other than "I know the password". Well, rather a lot. A password is content. While it's a foregone conclusion that this encrypted drive here in this case belongs to the suspect, the password may unlock other things that currently cannot be tied to the suspect. Maybe the courts have an answer to this problem, but in case they haven't, I thought I'd address this from a computer-science point of view.Firstly, we have to address the phrasing of entering a password, rather than disclosing the password. Clearly, the court is interested in only the content of the disk drive the password decrypts, and uninterested in the password itself. Yet, entering a password is the same as disclosing it. Technically, there's no way to enter a password in such a way that it can't be recorded. I don't know the law here, and whether courts would protect this disclosure, but for the purposes of this blog post, "entering" is treated the same as "disclosing".
Passwords have content. This paper focuses on one real, concrete example, but let's consider some hypothetical cases first.
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