I've been reading about the algorithm, and I've seen that a number of attacks against textbook RSA are based on encrypting shorter messages and checking the result. If padding does what I think it does (expand out the message to be the same length as the key), is it safe to forego padding if the message is guaranteed to be length of the key already?
As far as I know some padding schemes introduce random characters, so my gut tells me that it is required anyway to prevent against plaintext attacks.
Should I go for a smaller message size and add padding? Or is it safe to use m==n and no padding.