I would like to see an option for manipulating data with XOR (and maybe other basic binary functions) for basic obfuscation/encryption.
wxHexEditor has a unique function where it can apply a xor operation on the fly and preview the results in the hex display. This has proven useful to me for discovering and verifying the bit pattern quickly by comparing two files. Wx can also apply xor of arbitrary length, unlike other similar programs that only support byte-wise xor. But the basic interface of wxHexEditor isn't very good, which is why I'd like this enhancement in HxD.