"Box level" is apparently referring to types of cryptography, "S-boxes are non-linear transformations of a few input bits that provide confusion and P-boxes simply shuffle the input bits around to provide diffusion"[1] The basic function of S-Box[2] is to transform 8 bits input data into 8 bits of secret data using a precomputed look-up-table (LUT). A "permutation box (or P-box) is a method of bit-shuffling used to permute or transpose bits across S-boxes inputs, retaining diffusion while transposing."[3]

[1] https://www.linkedin.com/learning/symmetric-cryptography-ess...

[2] https://en.wikipedia.org/wiki/S-box

[3] https://en.wikipedia.org/wiki/Permutation_box

http://fileformats.archiveteam.org/wiki/Boxes/atoms_format

Encryption of boxes, not encryption with boxes. (the existence of AES sboxes is coincidental, and is not what was being discussed)

Let each of them know, please, that I and my compadres apologize for referring to MPEG-4 Part 2 as MP4 to save time, and refer to the container as MPEG-4 Part 14 to avoid ambiguity. Major faux pas there, how embarrassing, mea culpa, and thank you for taking the time to set us straight by letting us know what every single other person does.