I need to perform encryption on strings within PHP (few pages of text probably) at work with the following details:
If using the known encryption like AES, DES, 3DES and etc., I need to know what *exactly* is happening, in details. I should be able to pause at each step, and see the changes, and be able to reproduce it. Even a bit of modification on the core function is encouraged. This would unable me to use pre-defined encryption functions of PHP, since they don't show each step and work almost like a black box.
I have been reading about all these encryption algorithms for few weeks already, and so far I know that it may be very complicated if I want to code something like an AES in php on my own; though it is feasible. I have also seen that people would avoid it, because its very complicated and if one step is missed the whole idea is messed up!
I want to know your opinions about the situation:
Is it possible that I can modify one of these known encryption methods and implement by coding it myself inside PHP?
I have a encryption method proposal of my own which is not that complicated, but should be secure enough for my needs. So between the two, which one you would recommend? Modifying and using known ones, or produce a simple one myself?