帮忙看看这段密码转换的程序是如何转换的

[xiangyoung]

请尽可能详细解释下，谢谢。

Public Function PassWordConvert(Instring As String) 
Dim ConvertLength As Integer 
Dim PassConvBuf(0 To 99) As Byte 
For i = 1 To Len(Instring) 
PassConvBuf(i - 1) = Asc(Mid(Instring, i, 1)) 
Next i 

ConvertLength = Len(Instring) 

' 密码算法: 
' 每相邻两个码的和再高四位和低四位分别按位取反 

On Error Resume Next 
Dim Temp, temp1, temp2 As Byte 
For i = 0 To ConvertLength - 2 
Temp = (PassConvBuf(i) + PassConvBuf(i + 1)) And &HFF 
temp1 = Temp And &HF 
temp2 = (Temp And &HF0) / 16 
temp1 = Not temp1 
temp2 = Not temp2 
PassConvBuf(i) = (temp2 * 16 + temp1) And &HFF 
Next i 

Dim OutString As String 
For i = 0 To ConvertLength - 2 
OutString = OutString & Hex(PassConvBuf(i)) 
Next i 
PassWordConvert = OutString 
End Function

[用户 昵称]

建一个工程，调用一下就很容易明白了。

[aight]

帮顶。

[舉杯邀明月]

看在100分的份上，写一下解释吧：

Public Function PassWordConvert(Instring As String) 
    Dim ConvertLength As Integer
    Dim PassConvBuf(0 To 99) As Byte

    For i = 1 To Len(Instring)
        PassConvBuf(i - 1) = Asc(Mid(Instring, i, 1))
        '把 Instring 的每个字符的 ASCII码 依次填入 Byte数组 PassConvBuf 中。
        '注：这只能对西文字符串进行处理，有汉字就会产生溢出错误
    Next i

    ConvertLength = Len(Instring)
'    我觉得这句应该写在 For 循环之前，可以少调用一次函数。
'    ConvertLength = Len(Instring)
'    For i = 1 To ConvertLength
'        PassConvBuf(i - 1) = Asc(Mid(Instring, i, 1))
'    Next i

    ' 密码算法:
    ' 每相邻两个码的和再高四位和低四位分别按位取反
    On Error Resume Next    '出错时从下一句继续执行（偶的程序中从来不这样写 -_-! ）
    Dim Temp, temp1, temp2 As Byte
    '应该这样写：
    'Dim Temp As Byte, temp1 As Byte, temp2 As Byte
    For i = 0 To ConvertLength - 2
        Temp = (PassConvBuf(i) + PassConvBuf(i + 1)) And &HFF
        '把相邻两个字符的 ASCII码 相加，赋值给 Temp
        '前面那句的 (....) And &HFF 多此一举
        temp1 = Temp And &HF    '求Temp的 低4bit 的值
        temp2 = (Temp And &HF0) / 16    '求Temp的 高4bit 的值
        '要算高4位，写成： temp2 = Temp \ 16 岂不是直接了当？
        temp1 = Not temp1   '每位都取反
        temp2 = Not temp2
        PassConvBuf(i) = (temp2 * 16 + temp1) And &HFF
        '把temp2‘左移4位’与temp1相加，求低字节的值，赋值给 PassConvBuf(i)
    Next i

    Dim OutString As String
    For i = 0 To ConvertLength - 2
        OutString = OutString & Hex(PassConvBuf(i))
        '把转换后的“密码”用十六进制字符串的形式表示
    Next i
    PassWordConvert = OutString     '把这个十六进制字符串作为函数值返回
End Function

[舉杯邀明月]

其实这个算法是有问题的：

' 密码算法:
' 每相邻两个码的和再高四位和低四位分别按位取反
'..........
    Temp = (PassConvBuf(i) + PassConvBuf(i + 1)) And &HFF
     temp1 = Temp And &HF
     temp2 = (Temp And &HF0) / 16
     temp1 = Not temp1
     temp2 = Not temp2
    PassConvBuf(i) = (temp2 * 16 + temp1) And &HFF
'.........

它的结果并不是“每相邻两个码的和再高四位和低四位分别按位取反”

要“每相邻两个码的和再高四位和低四位分别按位取反”，这样写就行了：

For i = 0 To ConvertLength - 2
    PassConvBuf(i) = Not (PassConvBuf(i) + PassConvBuf(i + 1))
Next

要得到和原来的算法相同的结果：

For i = 0 To ConvertLength - 2
    PassConvBuf(i) = (Not (PassConvBuf(i) + PassConvBuf(i + 1)) - 16)
Next

[舉杯邀明月]

郁闷~~~~~
要得到和原来的算法相同的结果：

For i = 0 To ConvertLength - 2
    PassConvBuf(i) = (Not (PassConvBuf(i) + PassConvBuf(i + 1))) - 16
Next

[liguicd]

dinging