VB6 加密与解密

Private Sub Command1_Click()
    Dim aH
    aH = Hash(CStr(Text1.Text))
    Debug.Print aH
End Sub

Public Function Hash(ET As String) As String
    Dim BitLenString As String, KeyString As String, FileText As String
    BitLenString = "12345678"
    KeyString = ET & BitLenString
    Call Initialize(KeyString)
    '根据KeyString产生随机数序列
    FileText = ET & BitLenString
    Call DoXor(FileText)
    '根据上述随机数序列对FileText加密
    KeyString = FileText
    Call Initialize(KeyString)
    '根据上述的加密结果产生新的随机数序列
    FileText = BitLenString
    Call DoXor(FileText)
    '根据上述随机数序列对FileText加密，8位字符
    Hash = FileText
    '8位字符送作HASH值
End Function

Public Sub DoXor(ByRef msFileText As String)
    Dim intC As Integer
    Dim intB As Integer
    Dim lngI As Long
    '下面，用Rnd产生随机序列数，然后根据Int(Rnd * 2 ^ 7)得到一个对应整数，
    '再用该整数与msFileText中字符XOR.
    For lngI = 1 To Len(msFileText)
        intC = AscW(Mid(msFileText, lngI, 1))
        intB = Int(Rnd * 2 ^ 7)
        '选用< =127可正确处理汉字，ChrW(n):n 有一个范围
        Mid(msFileText, lngI, 1) = ChrW(intC Xor intB)
    Next lngI
End Sub

Private Sub Initialize(vKeyString As String)
    Dim intI As Integer, intJ As Integer
    Randomize Rnd(-1)  '得到初始值（种子值）
    '每次调用初始值均相同
    '根据初始值（种子值）得到随机数序列，每次调用Initialize时，初始值均相同。只要vKeyString相同，所产生的随机数序列一定相同
    For intI = 1 To Len(vKeyString)
        intJ = Rnd(-Rnd * AscW(Mid(vKeyString, intI, 1)))
        Randomize intJ
    Next intI
End Sub