Keskustelu: Ohjelmointikysymykset: VB6 ja RC4-kryptaus

Private Sub Command2_Click()
    Dim inbyte As Byte
    Dim z As Long
    Dim IntCheckFile As Integer
    Dim Tarkiste As Byte

    i = 0: j = 0

     Tunnari = "TUNNUS"

     RC4ini (Tunnari)


    Open App.Path & "\Password1.dat" For Binary As 1
    Open App.Path & "\Password.dat" For Binary As 2

    For z = 1 To LOF(1)
        Get #1, , inbyte
        Put #2, , EnDeCryptSingle(inbyte)
    Next z


    Close 1
    Close 2

End Sub

Private Sub Command1_Click()
    Dim inbyte As Byte
    Dim z As Long
    Dim Tarkiste

    Tunnari = "TUNNUS"

    i = 0: j = 0

    RC4ini (Tunnari)

    Open App.Path & "\Password.dat" For Binary As 1
    Open App.Path & "\Password1.dat" For Binary As 2

    For z = 1 To LOF(1)
        Get #1, , inbyte
        Put #2, , EnDeCryptSingle(inbyte)
    Next

    Close 1
    Close 2

End Sub

Option Explicit
Dim s(0 To 255) As Integer
Dim kep(0 To 255) As Integer
Dim i As Integer, j As Integer
Dim Tunnari As String

'Salasanan tallennus ja kryptaus
Public Sub RC4ini(Pwd As String)

    Dim temp As Integer, a As Integer, b As Integer
    b = 0
    'temp = 0 'testausta
    For a = 0 To 255
        b = b + 1
        If b > Len(Pwd) Then
            b = 1
        End If
        kep(a) = Asc(Mid$(Pwd, b, 1))
    Next a
    For a = 0 To 255
        s(a) = a
    Next a
    b = 0

    For a = 0 To 255
        b = (b + s(a) + kep(a)) Mod 256
        temp = s(a)
        s(a) = s(b)
        s(b) = temp
    Next a

End Sub


Public Function EnDeCryptSingle(plainbyte As Byte) As Byte
'RC4 kryptaus
    Dim temp As Integer, k As Integer
    Dim cipherby As Byte
    i = (i + 1) Mod 256
    j = (j + s(i)) Mod 256
    temp = s(i)
    s(i) = s(j)
    s(j) = temp
    k = s((s(i) + s(j)) Mod 256)
    cipherby = plainbyte Xor k
    EnDeCryptSingle = cipherby
End Function