@Skydriller I have more chance of getting the right question to that answer than understanding this one:)
So maybe we have to thing the other way round. What could it be?
Hint: It’s encrypted. Your task now: Find the cipher and the key.
Reminder hint: We have already established that base64 is a valid assumption and that the garbage characters are not garbage.
It could be just encrypted text, but all decent encryption produces data in which all byte values occur with equal probability, regardless of what known plaintext gets injected or suspected.
That the original data was (we assume) base64 encoded and, when decoded, doesn’t produce any values with the top bit set, must be indicating the encryption method, and it won’t be anything standard.
Maybe just one bit is being flipped, but it isn’t bit 7 (i.e. a XOR with 10000000) because that would convert text into values which all have the top bit set.
So how about laying out the data in binary and flipping 1 bit in each byte? The same one always.
When you undo the base64 you get garbled up data. So the encryption must have happened prior to base64.
Yes. Decode the original string and then look at flipping some bit.
Dimme wrote:
Base64 doesn’t have to decode to ASCII.
It can’t be base64 as it has special characters that are not used in base64.
Yes it can. Trust me. I made it.
Look outside the box and try to think what you can do with those special characters. I have basically given you the solution by now.
How about using those characters as a XOR for the string that follows each one?
