I think you misread; the government doesn't know the password. Nor are they interested in the password, per se; they are interested in the contents of the suspe

I think you misread; the government doesn't know the password. Nor are they interested in the password, per se; they are interested in the contents of the suspect's hard drive. Therefore, rather than ask for the password itself, which is information contained in his head and therefore arguably "testimony", they are merely compelling him to perform an "action" in decrypting the drive; he is free to keep the secret of the password itself.