一个加密解密函数 for vb6.0!

最新推荐文章于 2019-07-30 13:39:42 发布

原创最新推荐文章于 2019-07-30 13:39:42 发布 · 5k 阅读

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#解密 #vb #加密 #string #function #byte

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博客展示了VB语言中字符串加密和解密的函数实现。加密函数sumPassword将字符串转换为字节数组，通过随机数和异或运算加密，最后反转字符串；解密函数returnPassword则先反转字符串，再进行解密操作，将字节数组转换回字符串。

'= Name:         modPassword
'= Description: This function for string encrypt
'= Author:       Super.Wang
'= Date:         2004/11/01
'================================================
'= Please Do Not Remove These Comment Lines!
Public Function sumPassword(ByVal strSource As String) As String
    If Len(strSource) = 0 Then Exit Function
    Dim buff() As Byte
    buff = StrConv(strSource, vbFromUnicode)
    Dim i As Long
    Dim j As Byte
    Dim k As Byte, m As Byte
    Dim mstr As String
    mstr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz"
    Dim outs As String
    i = UBound(buff) + 1
    outs = Space(2 * i)
    Dim temps As String
    For i = 0 To UBound(buff)
        Randomize Time
        j = CByte(5 * (Math.Rnd()) + 0) '最大产生的随机数只能是5，不能再大了,再大的话，就要多用一个字节
        buff(i) = buff(i) Xor j
        k = buff(i) Mod Len(mstr)
        m = buff(i) / Len(mstr)
        m = m * 2 ^ 3 + j
        temps = Mid(mstr, k + 1, 1) + Mid(mstr, m + 1, 1)
        Mid(outs, 2 * i + 1, 2) = temps
     Next

        '将密码字符串反转
     Dim intTemp, intFor As Integer
     Dim strTemp, strOut As String
     intTemp = Len(outs)
     For intFor = 0 To intTemp - 1
        strTemp = Mid(outs, intTemp - intFor, 1)
        strOut = strOut + strTemp
     Next

     sumPassword = strOut
End Function
'还原密码，Super 04/11/1 改。
Public Function returnPassword(strPassword As String) As String
    On Error GoTo err

    '将密码字符串反转
     Dim intTemp, intFor As Integer
     Dim strTemp, strOut As String
     intTemp = Len(strPassword)
     For intFor = 0 To intTemp - 1
        strTemp = Mid(strPassword, intTemp - intFor, 1)
        strOut = strOut + strTemp
     Next
     strPassword = strOut


    '解密开始
    Dim i As Long
    Dim j As Byte
    Dim k As Byte
    Dim m As Byte
    Dim mstr As String
    mstr = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz"
    Dim t1 As String, t2 As String
    Dim buff() As Byte
    Dim n As Long
    n = 0
    For i = 1 To Len(strPassword) Step 2
        t1 = Mid(strPassword, i, 1)
        t2 = Mid(strPassword, i + 1, 1)
        k = InStr(1, mstr, t1) - 1
        m = InStr(1, mstr, t2) - 1
        j = m / 2 ^ 3
        m = m - j * 2 ^ 3
        ReDim Preserve buff(n)
        buff(n) = j * Len(mstr) + k
        buff(n) = buff(n) Xor m
        n = n + 1
     Next
     returnPassword = StrConv(buff, vbUnicode)

     Exit Function
err:
     returnPassword = ""
End Function