Looking at the python file they are complaining about, it simply implements the "encryption profile" that is mentioned. There is no circumvention; it still requires the user password. It is also clearly a novel implementation, so there is no copyright violation here. Their "algorithm" or whatever is obviously not protected under DMCA. So this is totally bogus, again. Bonus points for the DMCA notice obviously not bei…
(a)(3)(A) to “circumvent a technological measure” means to descramble a scrambled work, to decrypt an encrypted work, or otherwise to avoid, bypass, remove, deactivate, or impair a technological measure, without the authority of the copyright owner; and
(B) a technological measure “effectively controls access to a work” if the measure, in the ordinary course of its operation, requires the application of information, or a process or a treatment, with the authority of the copyright owner, to gain access to the work.
¹ yes, I know that it's weird to regard the algorithm as a secret when implementations are given out to the user[edited in response to correction by wtallis]