Can you tell me if my understanding of the problem is correct? Consider the following example:Animus wrote: ↑Wed May 06, 2020 8:11 amNo, that would have been encryption via substitution and has nothing to do with the described XOR encryption.The encryption key is is a series of (probably different) bytes, in this case of length 3. Which byte is used to XOR the input character does not depend on the value of that character, but only on its position in the text.Now what exactly is a decryption key? If it is supposed to give you the values for every letter, how can it consist of three characters?
There is no separate decryption key, it is the same as the encryption keyThe ASCII-value of the first character is XOR-ed with the value of the first encryption byte, the second character with the second byte and the third character with the third byte.What does it mean "the key is repeated cyclically throughout the message" and "as the encryption key consists of three lower case characters"?
Now, we have used all bytes of the encryption key and reuse it from the beginning. That is the forth character of the input text is XOR-ed with the first byte of the encryption key, the fifth with the second, and so on.
"the encryption key consists of three lower case characters" means that the three bytes of the encryption key contain the ASCII values of three lower case letters.
Suppose the original plain text was "HELLO WORLD", and the encryption key I chose was "97, 98, 99", which are the ascii values for a, b, c, respectively. To encrypt the plain text "HELLO WORLD", I would take the ascii value of H, which is 72, convert that to binary which is 1001000, then XOR the binary string using the binary value for 97 (1100010) to get the binary string 0101010, convert that to decimal (42), and finally take the associated ascii character (*) and present that as the encrypted form of H. I would then repeat this until all characters in HELLO WORLD are thus encrypted.
Do I understand the problem correctly?
EDIT: I've since solved this problem. Please my post below.