How to properly handle NUL character?

Question

PHP

Data is stored remotely in ASCII.
Example data (in the second column in the 16th system for understanding):
1) ]�1�*...� 5D 83 31 91 2A 12 00 D4
2) ]�1�*.� 5D 83 31 91 2A 1C 00 B9
3) ]�1�*‑�� 5D 83 31 91 2A 1E FF F0
4) ]�1�*.� 5D 83 31 91 2A 1F 0E F9
I get this data, convert it to 16ths using the bin2hex() function and save in the table. In another place, I pull it out of the table, convert it back with the hex2bin () function and send it for processing.
Items 1 and 2 contain '00' (NUL character), which is not displayed in any way in PHP, although it goes into the var_dump() character counter. As a result, records that contain this character cannot be processed correctly. As far as I could understand, this is due to the fact that the NUL character is not taken into account / lost / removed / cannot be processed by php (the <0x00> is not even displayed in the editor).
Tried to somehow catch this symbol to try to make a replacement, but could not find a way to catch "nothing".
Completely stumped. I would be glad to solve this problem or ideas in which direction to dig. Deleted data cannot be changed.

Answer 1

Data can be stored in a BLOB field https://dev.mysql.com/doc/refman/8.0/en/blob.html

As a result, records that contain this character cannot be processed correctly.

It is necessary to look at the processing functions, how it should be "correct" and how it turns out.