(defun encrypt (byte-list &optional (key 55665) (n 4) (c1 52845) (c2 22719))
  (loop :for byte :in (append (loop repeat n collect (random #xFF))
                              byte-list)
        :for r := key :then (mod (+ c2 (* c1 (+ cipher R)))#xFFFF)
        :for cipher := (logxor byte (ash R -8))
        :collect cipher))

To Encrypt a Sequence of Plaintext Bytes to Produce a
Sequence of Ciphertext Bytes
1. Generate n random bytes to be additional plaintext bytes at
the beginning of the sequence of plaintext bytes, for some
value of n.
2. Initialize an unsigned 16-bit integer variable R to the encryp-
tion key.
3. For each 8-bit byte, P, of plaintext (beginning with the newly
added random bytes) execute the following steps:
a. Assign the high order 8 bits of R to a temporary variable, T.
b. Exclusive-OR P with T, producing a ciphertext byte, C.
c. Compute the next value of R by the formula ((C + R) × c1 +
c2) mod 65536, where c1 is 52845 (decimal) and c2 is 22719
(decimal).
This encryption step can be performed by the following C lan-
guage program, where r is initialized to the key for the encryption
type:
unsigned short int r;
unsigned short int c1 = 52845;
unsigned short int c2 = 22719;
unsigned char Encrypt(plain) unsigned char plain;
{unsigned char cipher;
cipher = (plain ^ (r>>8));
r = (cipher + r) * c1 + c2;
return cipher;
}