Secret Agent Program

   0>REM SECRET AGENT PROGRAM MA
KES CODING AND DECODING CHILDSPL
AY,PROGRAM BY BILL HARMER,APR.19
85.ALL RIGHTS RESERVED
   1 REM
SECRET AGENT IS A PROGRAM FOR
THE SINCLAIR 2068 WHICH IS
DESIGNED TO MAKE CODING AND DE-
CODING CHILDSPLAY. ORIGINAL PRO-
GRAM BY BILL HARMER CONVERTED TO
THE 2068 BY DAVID SOLLY, OTTAWA,
ONTARIO, 1985.
   2 REM SECRET AGENT COPYRIGHT
   1985 BY BILL HARMER,OTTAWA-
   NON-COMMERCIAL NON-PROFIT USE
   AND THE MAKING OF ONE PERSONA
L  COPY ALLOWED BY TIMEX-SINCLAI
R  USER GROUP MEMBERS
   5 REM REVISED TS 2068
     VERSION 2.
  11 REM SECRET AGENT 8
     (FINISHED)
  30 CLS : POKE 23658,8
  50 DIM X(100)
  60 PRINT AT 10,0;"*         SE
CRET AGENT         *"
  65 PRINT AT 9,0;"*
                  *"
  67 PRINT AT 11,0;"*
                   *"
  70 PRINT AT 8,0;"*
                  *"
  72 PRINT AT 12,0;"*
                   *"
  75 PRINT AT 7,0;"*************
*******************"
  77 PRINT AT 13,0;"************
********************"
  90 PRINT ; FLASH 1;AT 21,0;"PR
ESS  ENTER  KEY TO GO ON"
  95 INPUT A$
  96 CLS
  97 IF A$="SESAME" THEN GO TO 9
000
 100 PRINT "SECRET AGENT IS A PR
OGRAM       DESIGNED TO ENCODE A
ND DECODE   SECRET MESSAGES"
 101 PRINT
 102 PRINT "A MESSAGE IS ENTERED
 AND THE    COMPUTER WILL CONVER
T IT TO A   SEQUENCE OF UNINTELL
IGIBLE      NUMBERS. THE MESSAGE
 CAN BE     DECIPHERED BY ANOTHE
R PERSON    HAVING THE SAME PROG
RAM"
 103 PRINT
 104 PRINT "ONE MUST KNOW HOWEVE
R WHICH OF  THE FOUR CODING OPTI
ONS HAVE    BEEN USED"
 105 PRINT
 106 PRINT "VARYING THE CODING O
PTION MAKES THE CODE MORE SECURE
"
 110 PRINT ; FLASH 1;AT 21,0;"PR
ESS ENTER TO GO ON"
 112 INPUT A$
 114 CLS
 115 PRINT ; FLASH 1;"ENTER"; FL
ASH 0;"  CODE  OR  DECODE  DEPEN
D-ING ON WHETHER YOU WISH TO COD
E A NEW MESSAGE OR DECODE A CODE
D MESSAGE"
 120 INPUT M$
 130 CLS
 140 PRINT ; FLASH 1;"ENTER"; FL
ASH 0;" WHICH CODE YOU  ARE USIN
G (1, 2, 3, OR 4)"
 150 INPUT W
 155 PRINT
 160 IF W<>1 AND W<>2 AND W<>3 A
ND W<>4 THEN PRINT AT 10,0;"ENTE
R ONLY ONE OF THE NUMBERS 1,2,3
OR 4. TRY AGAIN"
 170 IF W<>1 AND W<>2 AND W<>3 A
ND W<>4 THEN GO TO 150
 180 LET I=W
 190 IF W=2 THEN LET I=5
 200 IF W=4 THEN LET I=7
 210 REM "I" IS EXTRA INCREMENT
OF SUBSTITUTION,HERE SET TO 1,3,
5 OR 7 (BY CODE 1,3;2,4)
 220 CLS
 300 IF M$="CODE" OR M$="C" THEN
 GO TO 1000
 310 IF M$<>"CODE" AND M$<>"DECO
DE" AND M$<>"C" AND M$<>"D" THEN
 GO TO 115
 320 IF M$="D" OR M$="DECODE" TH
EN GO TO 2000
 330 GO TO 115
 950 PRINT : PRINT "THIS PROGRAM
 USES ";38912- FREE ;"BYTES"
 990 STOP
1000 REM ENCODING ROUTINE
1010 PRINT "PROGRAM TO CODE A NE
W MESSAGE"
1020 PRINT "USING CODE NUMBER ";
W
1030 PRINT
1040 PRINT "ENTER YOUR MESSAGE N
OW (UP TO   100 CHARACTERS=APPRO
X. 20 WORDS)"
1045 PRINT
1050 PRINT "IF YOUR MESSAGE IS L
ONGER BREAK IT UP INTO SMALLER M
ESSAGES AND CODE THEM SEPARATELY
"
1055 PRINT
1060 PRINT ; FLASH 1;"ENTER MESS
AGE NOW"
1070 INPUT R$
1080 CLS : PRINT ; FLASH 1;"WAIT
"
1085 PRINT : PRINT : PRINT
1100 LET F$=""
1110 REM IN OTHER COMPUTERS LINE
 1210 WOULD BE- U$=MID$(R$,N,1)
1200 FOR N=1 TO (LEN R$)
1210 LET U$=R$(N TO N)
1220 LET Y=(CODE (U$))
1225 IF Y<33 OR Y>90 THEN GO TO
1300
1226 REM Y<33 OR Y>90 WOULD BE U
SED FOR LINE 1225 FOR ASCII
1230 LET Y=Y+7+I
1232 REM ZX-81 VALUES 63 & 53
         IN LINE 1240
1240 IF Y>90 THEN LET Y=Y-58
1245 REM IF Y>90 THEN LET Y=Y-58
 WOULD BE USED FOR LINE 1240 FOR
ASCII
1250 LET T$=STR$ Y
1270 LET F$=F$+T$+","
1300 NEXT N
1310
1340 CLS : PRINT "MESSAGE IS:",,
F$
1400 PRINT AT 20,0;"PRESS ENTER
TO CODE AGAIN OR    ENTER  B  TO
 GO BACK TO START"
1410 INPUT A$
1420 CLS
1440 IF A$="B" OR A$="BEGIN" THE
N GO TO 100
1460 GO TO 1000
2000 REM DECODING ROUTINE
2010 PRINT "PROGRAM TO DECODE A
NEW MESSAGE"
2020 PRINT "USING CODE NUMBER ";
W
2030 PRINT
2040 PRINT "ENTER THE CODED TEXT
 COMPLETE    WITH COMMAS BETWEEN
THE NUMBERS"
2045 PRINT
2050 PRINT "UP TO 100 NUMBERS AR
E ALLOWED INTHE TEXT";
2055 PRINT "(NO SPACES ARE PLACE
D IN THE DECODED TEXT)"
2060 PRINT
2065 PRINT ; FLASH 1;"ENTER MESS
AGE NOW"
2070 INPUT P$
2080 CLS : PRINT ; FLASH 1;"WAIT
"
2085 PRINT : PRINT : PRINT
2090 LET G$=""
2100 REM IN OTHER COMPUTERS FOR
LINE 2210 SAY-U$=MID$(P$,N,1) AN
D 2215 V$=MID$(P$,N+1,1)
2200 FOR N=1 TO (LEN P$) STEP 3
2210 LET U$=P$(N TO N)
2215 LET V$=P$(N+1 TO N+1)
2217 LET M=((N-1)/3)+1
2220 LET X(M)=VAL (U$+V$)
2230 IF X(1)=0 THEN LET P$=F$
2235 IF X(1)=0 THEN GO TO 2090
2237 LET X(M)=(X(M)-7)-I
2240 IF X(M)<=32 THEN LET X(M)=X
(M)+58
2250 REM IF X(M)<33 THEN LET X(M
)=X(M)+58 FOR ASCII IN LINE 2240
2260 LET G$=G$+CHR$ (X(M))
2290 NEXT N
2295
2300 REM "0000"(4 ZEROS) ENTERED
 WILL RESULT IN PREVIOUSLY CODED
 TEXT BEING ENTERED FOR DECODING
 AS A TEST
2320 CLS : PRINT "MESSAGE IS:",,
G$
2350 PRINT AT 20,0;"PRESS ENTER
TO DECODE AGAIN OR  ENTER  B  TO
 GO BACK TO START"
2360 INPUT A$
2365 CLS
2370 IF A$="B" OR A$="BEGIN" THE
N GO TO 100
2380 GO TO 2000
9000 CLS : CLEAR
9010 PRINT "Cassette save begins
"
9020 SAVE "Spy" LINE 30
9030 SAVE "Spy" LINE 30
9040 CLS : PRINT "Verification.
Rewind and play"
9050 VERIFY "": VERIFY ""

Thanks To The Ottawa TSUG for the listing AND To Pheonix Pete for the RLE Graphics –