I wonder about this: What if the key to the encryption is written on a dozen seemingly random notes on yellow sticky notes in your office full of yellow sticky notes? Or, it is composed of the last letter on each page of a series of innocuous looking documents, such that the government might seize the documents but naturally in the process of doing so, scramble the documents order rendering the password irretrievable. Or its some combination of words from a book, or some other innocuous piece of material that they'd simply ignore and that would be thrown out after they left. The one FBI raid I'm directly familiar with involved them seizing the computers and even the phones, but not the desks or the phone books, etc.
In this case the passphrase existed in the location where the laptop was seized but in the intervening months, or in the act of seizing it, the phrase was destroyed. Thus it is the responsibility of the cops who seized it that the passphrase is no longer retrievable, and thus it is the government's fault the data is impossible to decrypt.
I'm sure there's an even better way to accomplish something similar that I'm not thinking of, where the phrase is kept handy, but only obvious to you so that you know how to derive it, but the simple act of serving a search warrant will eliminate the phrase by rearranging the key elements.
Then in court you can testify honestly to exactly how you looked up the phrase, but the government would have no way to recreate it.
In this case the passphrase existed in the location where the laptop was seized but in the intervening months, or in the act of seizing it, the phrase was destroyed. Thus it is the responsibility of the cops who seized it that the passphrase is no longer retrievable, and thus it is the government's fault the data is impossible to decrypt.
I'm sure there's an even better way to accomplish something similar that I'm not thinking of, where the phrase is kept handy, but only obvious to you so that you know how to derive it, but the simple act of serving a search warrant will eliminate the phrase by rearranging the key elements.
Then in court you can testify honestly to exactly how you looked up the phrase, but the government would have no way to recreate it.