random cube and a random location with that cube. The resulting "random" character is then XORed with the appropriate character of the plaintext. If someone can prove to me that this method is stupid
The way I understand this is that only one character is chosen and this same character is XORed with all plaintext for that session. Therefore, given that there are 8 bits in an unsigned char (which I am assuming you are using based on your choice of the word "character"), meaning that there are only 2^8 (256) possible 8 bit characters, hence only 256 different possible outcomes. Such a short keyspace is linearly searchable in a very small amount of time, making the encryption scheme particularly weak. If I am writing this based on a false understanding of your scheme, would you mind clarifying exactly the points in which I am in error, so that I might analyse with that information taken into account. Yours Sincerely, Benjamin Grosman