Code:
Public Function RC4(ByVal Expression As String, ByVal Password As String) As String On Error Resume Next Dim RB(0 To 255) As Integer, X As Long, Y As Long, Z As Long, Key() As Byte, ByteArray() As Byte, Temp As Byte If Len(Password) = 0 Then Exit Function End If If Len(Expression) = 0 Then Exit Function End If If Len(Password) > 256 Then Key() = StrConv(Left$(Password, 256), vbFromUnicode) Else Key() = StrConv(Password, vbFromUnicode) End If For X = 0 To 255 RB(X) = X Next X X = 0 Y = 0 Z = 0 For X = 0 To 255 Y = (Y + RB(X) + Key(X Mod Len(Password))) Mod 256 Temp = RB(X) RB(X) = RB(Y) RB(Y) = Temp Next X X = 0 Y = 0 Z = 0 ByteArray() = StrConv(Expression, vbFromUnicode) For X = 0 To Len(Expression) Y = (Y + 1) Mod 256 Z = (Z + RB(Y)) Mod 256 Temp = RB(Y) RB(Y) = RB(Z) RB(Z) = Temp ByteArray(X) = ByteArray(X) Xor (RB((RB(Y) + RB(Z)) Mod 256)) Next X RC4 = StrConv(ByteArray, vbUnicode) End Function