anew en_de_crypt.f

Needs apps\Chess\toolset.f

\ A simple encrypt/decrypt tool. It Uses one key.

: encryption-key ( - adr count  )    s" 4ePost"  ;

: encrypt/decrypt$ ( orginal$|encrypted$ count - encrypted$|orginal$ count )
   encryption-key third 0 locals| key-char cnt max-key |
   -rot 0
       do   i  max-key /mod drop third + c@ to key-char  \ key-char
            dup i + c@                                   \ char to encript/decript
            dup i 1+ key-char + 8 /mod drop tuck test-bit not swap bit! \ encript/decript
            i tmp$ + c!                                  \ store it
       loop
    2drop tmp$ cnt
   ;


\s Use

s" Secret" encrypt/decrypt$ 2dup dump .(  Encrypted) cr encrypt/decrypt$  dump .(  Decrypted)

\s
\ Shows:

  43B185 | 73 E5 6B 7A 64 70                                |såkzdp| Encrypted

  43B185 | 53 65 63 72 65 74                                |Secret| Decrypted