制作登陆行为时可能需要用到MD5加密用户密码,使用ASP实现这个功能比其他语言稍微麻烦一点,但是也是可行的.

核心代码:

<%
Private Const BITS_TO_A_BYTE = 8
Private Const BYTES_TO_A_WORD = 4
Private Const BITS_TO_A_WORD = 32

Private m_lOnBits(30)
Private m_l2Power(30)

Private Function LShift(lValue, iShiftBits)
  If iShiftBits = 0 Then
    LShift = lValue
    Exit Function
  ElseIf iShiftBits = 31 Then
    If lValue And 1 Then
      LShift = &H80000000
    Else
      LShift = 0
    End If
    Exit Function
  ElseIf iShiftBits < 0 Or iShiftBits > 31 Then
    Err.Raise 6
  End If

  If (lValue And m_l2Power(31 - iShiftBits)) Then
    LShift = ((lValue And m_lOnBits(31 - (iShiftBits + 1))) * m_l2Power(iShiftBits)) Or &H80000000
  Else
    LShift = ((lValue And m_lOnBits(31 - iShiftBits)) * m_l2Power(iShiftBits))
  End If
End Function

Private Function RShift(lValue, iShiftBits)
  If iShiftBits = 0 Then
    RShift = lValue
    Exit Function
  ElseIf iShiftBits = 31 Then
    If lValue And &H80000000 Then
      RShift = 1
    Else
      RShift = 0
    End If
    Exit Function
  ElseIf iShiftBits < 0 Or iShiftBits > 31 Then
    Err.Raise 6
  End If
 
  RShift = (lValue And &H7FFFFFFE)  m_l2Power(iShiftBits)

  If (lValue And &H80000000) Then
    RShift = (RShift Or (&H40000000  m_l2Power(iShiftBits - 1)))
  End If
End Function

Private Function RotateLeft(lValue, iShiftBits)
  RotateLeft = LShift(lValue, iShiftBits) Or RShift(lValue, (32 - iShiftBits))
End Function

Private Function AddUnsigned(lX, lY)
  Dim lX4
  Dim lY4
  Dim lX8
  Dim lY8
  Dim lResult

  lX8 = lX And &H80000000
  lY8 = lY And &H80000000
  lX4 = lX And &H40000000
  lY4 = lY And &H40000000

  lResult = (lX And &H3FFFFFFF) + (lY And &H3FFFFFFF)

  If lX4 And lY4 Then
    lResult = lResult Xor &H80000000 Xor lX8 Xor lY8
  ElseIf lX4 Or lY4 Then
    If lResult And &H40000000 Then
      lResult = lResult Xor &HC0000000 Xor lX8 Xor lY8
    Else
      lResult = lResult Xor &H40000000 Xor lX8 Xor lY8
    End If
  Else
    lResult = lResult Xor lX8 Xor lY8
  End If

  AddUnsigned = lResult
End Function