DIM clefC(1 TO 14) AS INTEGER
DIM clefD(1 TO 14) AS INTEGER
DIM fun1(1 TO 21)
DIM fun3(1 TO 14)
DIM c(1 TO 9)
DIM k(1 TO 9)
DIM octet AS STRING * 1
DIM octet11 AS STRING * 1
DIM octet12(1 TO 2) AS STRING * 1
DIM octet13(1 TO 3) AS STRING * 1
DIM code(1 TO 14)
DIM clef AS STRING
DIM i AS INTEGER
DIM archive AS STRING
DIM longclef AS STRING * 1

PRINT "Entrez le nom du fichier a traiter :"
INPUT archive$

fun1(1) = 20
fun1(2) = 67
fun1(3) = 82
fun1(4) = 89
fun1(5) = 80
fun1(6) = 84
fun1(7) = 40
fun1(8) = 67
fun1(9) = 41
fun1(10) = 67
fun1(11) = 79
fun1(12) = 84
fun1(13) = 69
fun1(14) = 76
fun1(15) = 69
fun1(16) = 77
fun1(17) = 32
fun1(18) = 49
fun1(19) = 57
fun1(20) = 57
fun1(21) = 55

c(1) = 161
c(2) = 47
c(3) = 7
c(4) = 157
c(5) = 21
c(6) = 196
c(7) = 55
c(8) = 10
c(9) = 32

k(1) = 73
k(2) = 77
k(3) = 65
k(4) = 71
k(5) = 69
k(6) = 83
k(7) = 0
k(8) = 0
k(9) = 0

OPEN archive$ FOR RANDOM AS #1 LEN = 1

FOR i = 1 TO 21
PRINT i
GET #1, i, octet
IF ASC(octet) <> fun1(i) THEN GOTO Erreur
NEXT i
GOTO suite

Erreur:
PRINT "Fichier non COTELEM"
CLOSE #1
GOTO fin

suite:
GET #1, 188, longclef
FOR i = 1 TO 9
i = i + 380
GET #1, i, octet
i = i - 380
fun3(i) = 255 XOR ASC(octet)
fun3(i) = 2 * fun3(i)
IF fun3(i) > 255 THEN fun3(i) = fun3(i) - 255
fun3(i) = NOT (fun3(i))
IF fun3(i) < 0 THEN fun3(i) = fun3(i) + 256
NEXT i

GET #1, 402, octet12(1)
GET #1, 403, octet12(2)
GET #1, 403, octet13(1)
GET #1, 404, octet13(2)
GET #1, 405, octet13(3)
GET #1, 423, octet11

CLOSE #1

FOR i = 1 TO 9
code(i) = c(i) XOR k(i)
code(i) = fun3(i) XOR code(i)
clefC(i) = code(i)
NEXT i
IF ASC(longclef) = 11 THEN
 fun3(10) = 255 XOR ASC(octet11)
 fun3(10) = 2 * fun3(10)
 IF fun3(10) > 255 THEN fun3(10) = fun3(10) - 255
 fun3(10) = NOT (fun3(10))
 IF fun3(10) < 0 THEN fun3(10) = fun3(10) + 256
 code(10) = fun3(10) XOR 84
 clefC(10) = code(10) - 3
 END IF

IF ASC(longclef) = 12 THEN
 FOR i = 10 TO 11
 fun3(i) = 255 XOR ASC(octet12(i - 9))
 fun3(i) = 2 * fun3(i)
 IF fun3(i) > 255 THEN fun3(i) = fun3(i) - 255
 fun3(i) = NOT (fun3(i))
 IF fun3(i) < 0 THEN fun3(i) = fun3(i) + 256
 NEXT i
 code(10) = fun3(10) XOR 49
 clefC(10) = code(10) - 1
 code(11) = fun3(11) XOR 55
 clefC(11) = code(11) - 1
 END IF

IF ASC(longclef) = 13 THEN
 FOR i = 10 TO 12
 fun3(i) = 255 XOR ASC(octet13(i - 9))
 fun3(i) = 2 * fun3(i)
 IF fun3(i) > 255 THEN fun3(i) = fun3(i) - 255
 fun3(i) = NOT (fun3(i))
 IF fun3(i) < 0 THEN fun3(i) = fun3(i) + 256
 NEXT i
 code(10) = fun3(10) XOR 55
 clefC(10) = code(10) - 1
 code(11) = fun3(11) XOR 84
 clefC(11) = code(11) - 1
 code(12) = fun3(12) XOR 79
 clefC(12) = code(12) - 1
END IF

clefC(ASC(longclef)) = ASC("Q")

clefD(1) = clefC(5)
clefD(2) = clefC(2)
clefD(3) = clefC(6)
clefD(4) = clefC(10)
clefD(5) = clefC(4)
clefD(6) = clefC(9)
clefD(7) = clefC(3)
clefD(8) = clefC(8)
clefD(9) = clefC(7)
clefD(10) = clefC(1)
clefD(11) = clefC(11)
clefD(12) = clefC(12)
clefD(13) = clefC(13)

PRINT "Cle proposee :"
FOR i = 1 TO ASC(longclef)
 PRINT CHR$(clefD(i)); "";
NEXT i
PRINT
fin:
END