给你两个函数自己看看吧
Public Function Encrypt(ByVal secret As String, ByVal PassWord As String) As String
Dim L As Integer
Dim X As Integer
Dim Ch As Integer
L = Len(PassWord)
For X = 1 To Len(secret)
Ch = Asc(Mid(PassWord), 1))
Mid(secret, X, 1) = Chr(Asc(Mid(secret, X, 1)) Xor Ch)
Next
Return secret
End Function