The answer is highly dependent on the platform and development tool, but overall there is no reliable solution. The encryption function is the point at which the key must be present in its "natural" form. Thus, all the hacker needs is to set a breakpoint and reset the key. There is no need to even decompile anything. Therefore, any obfuscation is good only for beginners or when debugging is not possible for any reason. Using the text string that exists in the application, since the key is one of the options.
, , . (, IMEI) . , , (, - ).
, , , .
, - . , (USB- -) - . , .