I am writing an article on encryption.
As part of the article I am putting forward a custom encryption scheme that will serve as an example.
I'm not suggesting that it's a new or better encryption method or that anyone actually use it, but I know the onus is on the author of an algorithm to prove how secure it is, and I'd like to cover that in the article.
I don't actually want to prove the encryption, I just want to explain the steps that would be required - if only to show why it's way more effort to create your own encryption than using a pre-existing implementation.
I'd like to do this clearly, without the reader needing to know mathematical notations.
What I have tried:
I am already covering some of the basics that are used to attack an encryption - statistical analysis of symbol distribution, rendering hash tables, common-header attacks, plaintext-ciphertext collisions, that sort of thing.
I can show comparisons with the clear data to prove all the bytes have changed, and histogram analysis of the symbols in the encrypted file shows that every byte value (0 - 255) is used, and used about the same number of times, and that you can't reveal the key by trying to guess at the data and XORing that with the encrypted values (the algorithm uses an IV, block-cipher-chaining, padding, inversion and two separate key streams)
Can anyone think of more ways to attack a cipher?