Transformations An enciphering transformation (also called an enciphering function)is a bijective function Ee MC, where the key e EK uniquely determines Ee acting upon plaintert message units m E M to get ciphertert message units Ee(m)=c∈C. A deciphering transformation (or deciphering function)is a bijective function Da:e→M, which is uniquely determined by a given key d E K,acting upon ciphertext message units c Ee to get plaintert message units Da(c)=m. The application of Ee to m,namely the operation Ee(m),is called enciphering, encoding,or encrypting m E M,whereas the application of Da to c is called deciphering,decoding,or decrypting ceC.Transformations