QQ加密的逆算法编写

'复制代码
Public Function Base64Decode(cString As String) As String 'QQ版Base64解码
Dim dStr As String, tStr As String
Dim i As Integer
Dim l As Integer
l = Len(cString) - 2 '减去两个等号的空间(不减也行)
For i = 1 To l
dStr = HexBase64_1(Mid(cString, i, 1))
tStr = tStr & Hex2Bin(Left(dStr, 1)) & Hex2Bin(Right(dStr, 1))
Next i
l = Len(tStr)
dStr = ""
For i = 3 To l Step 8
dStr = dStr & Mid(tStr, i, 6)
Next i
l = Len(dStr)
For i = 1 To l Step 4
Base64Decode = Base64Decode & Bin2Hex(Mid(dStr, i, 4))
Next i
If Len(Base64Decode) > 32 Then Base64Decode = Left(Base64Decode, 32)
End Function
Private Function Bin2Hex(BinStr1 As String) As String
Select Case BinStr1
'2进制转换16进制
Case "0000": Bin2Hex = "0"
Case "0001": Bin2Hex = "1"
Case "0010": Bin2Hex = "2"
Case "0011": Bin2Hex = "3"
Case "0100": Bin2Hex = "4"
Case "0101": Bin2Hex = "5"