10 ; "Infil:"; : INPUT F1$
20 ; "Utfil:"; : INPUT F2$
30 ; "Kryptering eller dekryptering? (K/D)"
40 GET C$
50 IF (ASC(C$) AND 223%)=75 THEN Y%=1% ELSE IF (ASC(C$) AND 223%)=68% THEN Y%=0% ELSE 40
60 X%=95%
70 IF Y% THEN ; "Kryptering!" ELSE ; "Dekryptering"
80 DIM A$=119,B$=119
90 ; "Giv startnyckel:";
100 FOR I%=1 TO 5
110 GET A$ : ; A$; : GET B$ : ; B$; : POKE -456%+I%,ASC(A$)+ASC(B$)
120 NEXT I%
130 OPEN F1$ ASFILE 1
140 PREPARE F2$ ASFILE 2
150 ONERRORGOTO 270
160 FOR I%=1 TO 1000
170 INPUTLINE #1,B$ : B$=LEFT$(B$,LEN(B$)-2%)
180 A$=""
190 FOR J%=1 TO LEN(B$)
200 Z0%=X%*RND
210 IF Y% THEN Z%=ASC(RIGHT$(B$,J%))+Z0% ELSE Z%=ASC(RIGHT$(B$,J%))-Z0%
220 IF Z%>126% THEN Z%=Z%-X% ELSE IF Z%<32% THEN Z%=Z%+X%
230 A$=A$+CHR$(Z%)
240 NEXT J%
250 ; #2,A$
260 NEXT I%
270 IF ERRCODE=34 THEN CLOSE 2 ELSE ; "Fel nr";ERRCODE
280 END