CRYPT / DECRYPT / KEYGEN : UN MODULE CLAIR ET EXTRENEMENT UTILE !

'Tout petit : 3 subs : Aucune gestion des Erreurs mais c'est prévu pour ne pas avoir les Erreurs stupides, cad celles qui sont dues à une réécriture sur un fichier (l'effacement du fichier est automatique si il existe)

'C'est le module, si vous ne voulez pas apprendre mais vous en servir, décompacter le ZIP avec votre programme et ajouter le module à votre programme.
'Vous pourrez dés lors utiliser les instructions :
'-CRYPT pour crypter
'-DECRYPT pour décrypter
'-KEYGEN pour générer une clef randomizer

Sub Crypt(Clef As String, Source As String, Destination As String)
Dim a As Integer
Dim b As Double
Dim c As String * 1
Dim K(0 To 255) As Integer
Open Clef For Random As #1 Len = 1
For a = 1 To 256
    Get #1, a, c
    K(a - 1) = Asc(c)
Next a
Close
If Len(Dir(Destination, 14)) > 0 Then Kill Destination
Open Source For Random As #1 Len = 1
Open Destination For Random As #2 Len = 1
For b = 1 To LOF(1)
    Get #1, b, c
    c = Chr(K(Asc(c)))
    Put #2, b, c
Next b
Close
End Sub

Sub Decrypt(Clef As String, Source As String, Destination As String)
Dim a As Integer
Dim b As Double
Dim c As String * 1
Dim K(0 To 255) As Integer
Open Clef For Random As #1 Len = 1
For a = 1 To 256
    Get #1, a, c
    K(Asc(c)) = a - 1
Next a
Close
If Len(Dir(Destination, 14)) > 0 Then Kill Destination
Open Source For Random As #1 Len = 1
Open Destination For Random As #2 Len = 1
For b = 1 To LOF(1)
    Get #1, b, c
    c = Chr(K(Asc(c)))
    Put #2, b, c
Next b
Close
End Sub

Sub KeyGen(Destination As String)
Dim a As Integer
Dim b As Integer
Dim c As String * 1
Dim K(0 To 255) As Integer
For a = 0 To 255
    K(a) = a
Next a
Randomize Timer
If Len(Dir(Destination, 14)) > 0 Then Kill Destination
Open Destination For Random As #1 Len = 1
For a = 1 To 256
    Do
        b = Int(Rnd * 256)
    Loop While K(b) < 0
    c = Chr$(K(b))
    Put #1, a, c
    K(b) = -1
Next a
Close
End Sub