md5是一種不可逆的加密方式，對于某些敏感信息應(yīng)該加密處理，這樣，即使其他人得到了加密后的結(jié)果，也不可能知道有效的口令。

對用戶的口令加密也是網(wǎng)站管理員的職業(yè)道德。某些口令可能會泄漏用戶的密碼習慣。

md5.asp

包含了一個md5函數(shù)

使用方法

dim abc:abc="www.aspxuexi.com"

abc=md5(abc,16)  ´16位md5加密

Response.write abc

<%
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)
Dim Md5OLD
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 str2bin(varstr)
    Dim varasc
    Dim i
    Dim varchar
    Dim varlow
    Dim varhigh
   
 str2bin=""
    For i=1 To Len(varstr)
        varchar=mid(varstr,i,1)
        varasc = Asc(varchar)
       
        If varasc<0 Then
        varasc = varasc + 65535
        End If
       
        If varasc>255 Then
        varlow = Left(Hex(Asc(varchar)),2)
        varhigh = right(Hex(Asc(varchar)),2)
        str2bin = str2bin & chrB("&H" & varlow) & chrB("&H" & varhigh)
        Else
        str2bin = str2bin & chrB(AscB(varchar))
        End If
    Next
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

Private Function md5_F(x, y, z)
 md5_F = (x And y) Or ((Not x) And z)
End Function

Private Function md5_G(x, y, z)
 md5_G = (x And z) Or (y And (Not z))
End Function

Private Function md5_H(x, y, z)
 md5_H = (x Xor y Xor z)
End Function

Private Function md5_I(x, y, z)
 md5_I = (y Xor (x Or (Not z)))
End Function

Private Sub md5_FF(a, b, c, d, x, s, ac)
 a = AddUnsigned(a, AddUnsigned(AddUnsigned(md5_F(b, c, d), x), ac))
 a = RotateLeft(a, s)
 a = AddUnsigned(a, b)
End Sub

Private Sub md5_GG(a, b, c, d, x, s, ac)
 a = AddUnsigned(a, AddUnsigned(AddUnsigned(md5_G(b, c, d), x), ac))
 a = RotateLeft(a, s)
 a = AddUnsigned(a, b)
End Sub

Private Sub md5_HH(a, b, c, d, x, s, ac)
 a = AddUnsigned(a, AddUnsigned(AddUnsigned(md5_H(b, c, d), x), ac))
 a = RotateLeft(a, s)
 a = AddUnsigned(a, b)
End Sub

Private Sub md5_II(a, b, c, d, x, s, ac)
 a = AddUnsigned(a, AddUnsigned(AddUnsigned(md5_I(b, c, d), x), ac))
 a = RotateLeft(a, s)
 a = AddUnsigned(a, b)
End Sub

Private Function ConvertToWordArray(sMessage)
 Dim lMessageLength
 Dim lNumberOfWords
 Dim lWordArray()
 Dim lBytePosition
 Dim lByteCount
 Dim lWordCount
 Const MODULUS_BITS = 512
 Const CONGRUENT_BITS = 448
 If Md5OLD = 1 Then
  lMessageLength = Len(sMessage)
 Else
  lMessageLength = LenB(sMessage)
 End If
 lNumberOfWords = (((lMessageLength + ((MODULUS_BITS - CONGRUENT_BITS) \ BITS_TO_A_BYTE)) \ (MODULUS_BITS \ BITS_TO_A_BYTE)) + 1) * (MODULUS_BITS \ BITS_TO_A_WORD)
 ReDim lWordArray(lNumberOfWords - 1)
 
 lBytePosition = 0
    lByteCount = 0
 Do Until lByteCount >= lMessageLength
  lWordCount = lByteCount \ BYTES_TO_A_WORD
  lBytePosition = (lByteCount Mod BYTES_TO_A_WORD) * BITS_TO_A_BYTE
  If Md5OLD = 1 Then
   lWordArray(lWordCount) = lWordArray(lWordCount) Or LShift(Asc(Mid(sMessage, lByteCount + 1, 1)), lBytePosition)
  Else
   lWordArray(lWordCount) = lWordArray(lWordCount) Or LShift(AscB(MidB(sMessage, lByteCount + 1, 1)), lBytePosition)
  End If
  lByteCount = lByteCount + 1
 Loop
 lWordCount = lByteCount \ BYTES_TO_A_WORD
 lBytePosition = (lByteCount Mod BYTES_TO_A_WORD) * BITS_TO_A_BYTE
 lWordArray(lWordCount) = lWordArray(lWordCount) Or LShift(&H80, lBytePosition)
 lWordArray(lNumberOfWords - 2) = LShift(lMessageLength, 3)
 lWordArray(lNumberOfWords - 1) = RShift(lMessageLength, 29)
 ConvertToWordArray = lWordArray
End Function

Private Function WordToHex(lValue)
 Dim lByte
 Dim lCount
 For lCount = 0 To 3
  lByte = RShift(lValue, lCount * BITS_TO_A_BYTE) And m_lOnBits(BITS_TO_A_BYTE - 1)
  WordToHex = WordToHex & Right("0" & Hex(lByte), 2)
 Next
End Function

Public Function MD5(sMessage,stype)
 m_lOnBits(0) = CLng(1)
 m_lOnBits(1) = CLng(3)
 m_lOnBits(2) = CLng(7)
 m_lOnBits(3) = CLng(15)
 m_lOnBits(4) = CLng(31)
 m_lOnBits(5) = CLng(63)
 m_lOnBits(6) = CLng(127)
 m_lOnBits(7) = CLng(255)
 m_lOnBits(8) = CLng(511)
 m_lOnBits(9) = CLng(1023)
 m_lOnBits(10) = CLng(2047)
 m_lOnBits(11) = CLng(4095)
 m_lOnBits(12) = CLng(8191)
 m_lOnBits(13) = CLng(16383)
 m_lOnBits(14) = CLng(32767)
 m_lOnBits(15) = CLng(65535)
 m_lOnBits(16) = CLng(131071)
 m_lOnBits(17) = CLng(262143)
 m_lOnBits(18) = CLng(524287)
 m_lOnBits(19) = CLng(1048575)
 m_lOnBits(20) = CLng(2097151)
 m_lOnBits(21) = CLng(4194303)
 m_lOnBits(22) = CLng(8388607)
 m_lOnBits(23) = CLng(16777215)
 m_lOnBits(24) = CLng(33554431)
 m_lOnBits(25) = CLng(67108863)
 m_lOnBits(26) = CLng(134217727)
 m_lOnBits(27) = CLng(268435455)
 m_lOnBits(28) = CLng(536870911)
 m_lOnBits(29) = CLng(1073741823)
 m_lOnBits(30) = CLng(2147483647)
 
 m_l2Power(0) = CLng(1)
 m_l2Power(1) = CLng(2)
 m_l2Power(2) = CLng(4)
 m_l2Power(3) = CLng(8)
 m_l2Power(4) = CLng(16)
 m_l2Power(5) = CLng(32)
 m_l2Power(6) = CLng(64)
 m_l2Power(7) = CLng(128)
 m_l2Power(8) = CLng(256)
 m_l2Power(9) = CLng(512)
 m_l2Power(10) = CLng(1024)
 m_l2Power(11) = CLng(2048)
 m_l2Power(12) = CLng(4096)
 m_l2Power(13) = CLng(8192)
 m_l2Power(14) = CLng(16384)
 m_l2Power(15) = CLng(32768)
 m_l2Power(16) = CLng(65536)
 m_l2Power(17) = CLng(131072)
 m_l2Power(18) = CLng(262144)
 m_l2Power(19) = CLng(524288)
 m_l2Power(20) = CLng(1048576)
 m_l2Power(21) = CLng(2097152)
 m_l2Power(22) = CLng(4194304)
 m_l2Power(23) = CLng(8388608)
 m_l2Power(24) = CLng(16777216)
 m_l2Power(25) = CLng(33554432)
 m_l2Power(26) = CLng(67108864)
 m_l2Power(27) = CLng(134217728)
 m_l2Power(28) = CLng(268435456)
 m_l2Power(29) = CLng(536870912)
 m_l2Power(30) = CLng(1073741824)
 
 
 Dim x
 Dim k
 Dim AA
 Dim BB
 Dim CC
 Dim DD
 Dim a
 Dim b
 Dim c
 Dim d
 
 Const S11 = 7
 Const S12 = 12
 Const S13 = 17
 Const S14 = 22
 Const S21 = 5
 Const S22 = 9
 Const S23 = 14
 Const S24 = 20
 Const S31 = 4
 Const S32 = 11
 Const S33 = 16
 Const S34 = 23
 Const S41 = 6
 Const S42 = 10
 Const S43 = 15
 Const S44 = 21
 If Md5OLD = 1 Then
  x = ConvertToWordArray(sMessage)
 Else
  x = ConvertToWordArray(str2bin(sMessage))
 End If
 a = &H67452301
 b = &HEFCDAB89
 c = &H98BADCFE
 d = &H10325476
 
 For k = 0 To UBound(x) Step 16
  AA = a
  BB = b
  CC = c
  DD = d
  
  md5_FF a, b, c, d, x(k + 0), S11, &HD76AA478
  md5_FF d, a, b, c, x(k + 1), S12, &HE8C7B756
  md5_FF c, d, a, b, x(k + 2), S13, &H242070DB
  md5_FF b, c, d, a, x(k + 3), S14, &HC1BDCEEE
  md5_FF a, b, c, d, x(k + 4), S11, &HF57C0FAF
  md5_FF d, a, b, c, x(k + 5), S12, &H4787C62A
  md5_FF c, d, a, b, x(k + 6), S13, &HA8304613
  md5_FF b, c, d, a, x(k + 7), S14, &HFD469501
  md5_FF a, b, c, d, x(k + 8), S11, &H698098D8
  md5_FF d, a, b, c, x(k + 9), S12, &H8B44F7AF
  md5_FF c, d, a, b, x(k + 10), S13, &HFFFF5BB1
  md5_FF b, c, d, a, x(k + 11), S14, &H895CD7BE
  md5_FF a, b, c, d, x(k + 12), S11, &H6B901122
  md5_FF d, a, b, c, x(k + 13), S12, &HFD987193
  md5_FF c, d, a, b, x(k + 14), S13, &HA679438E
  md5_FF b, c, d, a, x(k + 15), S14, &H49B40821
  
  md5_GG a, b, c, d, x(k + 1), S21, &HF61E2562
  md5_GG d, a, b, c, x(k + 6), S22, &HC040B340
  md5_GG c, d, a, b, x(k + 11), S23, &H265E5A51
  md5_GG b, c, d, a, x(k + 0), S24, &HE9B6C7AA
  md5_GG a, b, c, d, x(k + 5), S21, &HD62F105D
  md5_GG d, a, b, c, x(k + 10), S22, &H2441453
  md5_GG c, d, a, b, x(k + 15), S23, &HD8A1E681
  md5_GG b, c, d, a, x(k + 4), S24, &HE7D3FBC8
  md5_GG a, b, c, d, x(k + 9), S21, &H21E1CDE6
  md5_GG d, a, b, c, x(k + 14), S22, &HC33707D6
  md5_GG c, d, a, b, x(k + 3), S23, &HF4D50D87
  md5_GG b, c, d, a, x(k + 8), S24, &H455A14ED
  md5_GG a, b, c, d, x(k + 13), S21, &HA9E3E905
  md5_GG d, a, b, c, x(k + 2), S22, &HFCEFA3F8
  md5_GG c, d, a, b, x(k + 7), S23, &H676F02D9
  md5_GG b, c, d, a, x(k + 12), S24, &H8D2A4C8A
  
  md5_HH a, b, c, d, x(k + 5), S31, &HFFFA3942
  md5_HH d, a, b, c, x(k + 8), S32, &H8771F681
  md5_HH c, d, a, b, x(k + 11), S33, &H6D9D6122
  md5_HH b, c, d, a, x(k + 14), S34, &HFDE5380C
  md5_HH a, b, c, d, x(k + 1), S31, &HA4BEEA44
  md5_HH d, a, b, c, x(k + 4), S32, &H4BDECFA9
  md5_HH c, d, a, b, x(k + 7), S33, &HF6BB4B60
  md5_HH b, c, d, a, x(k + 10), S34, &HBEBFBC70
  md5_HH a, b, c, d, x(k + 13), S31, &H289B7EC6
  md5_HH d, a, b, c, x(k + 0), S32, &HEAA127FA
  md5_HH c, d, a, b, x(k + 3), S33, &HD4EF3085
  md5_HH b, c, d, a, x(k + 6), S34, &H4881D05
  md5_HH a, b, c, d, x(k + 9), S31, &HD9D4D039
  md5_HH d, a, b, c, x(k + 12), S32, &HE6DB99E5
  md5_HH c, d, a, b, x(k + 15), S33, &H1FA27CF8
  md5_HH b, c, d, a, x(k + 2), S34, &HC4AC5665
  
  md5_II a, b, c, d, x(k + 0), S41, &HF4292244
  md5_II d, a, b, c, x(k + 7), S42, &H432AFF97
  md5_II c, d, a, b, x(k + 14), S43, &HAB9423A7
  md5_II b, c, d, a, x(k + 5), S44, &HFC93A039
  md5_II a, b, c, d, x(k + 12), S41, &H655B59C3
  md5_II d, a, b, c, x(k + 3), S42, &H8F0CCC92
  md5_II c, d, a, b, x(k + 10), S43, &HFFEFF47D
  md5_II b, c, d, a, x(k + 1), S44, &H85845DD1
  md5_II a, b, c, d, x(k + 8), S41, &H6FA87E4F
  md5_II d, a, b, c, x(k + 15), S42, &HFE2CE6E0
  md5_II c, d, a, b, x(k + 6), S43, &HA3014314
  md5_II b, c, d, a, x(k + 13), S44, &H4E0811A1
  md5_II a, b, c, d, x(k + 4), S41, &HF7537E82
  md5_II d, a, b, c, x(k + 11), S42, &HBD3AF235
  md5_II c, d, a, b, x(k + 2), S43, &H2AD7D2BB
  md5_II b, c, d, a, x(k + 9), S44, &HEB86D391
  
  a = AddUnsigned(a, AA)
  b = AddUnsigned(b, BB)
  c = AddUnsigned(c, CC)
  d = AddUnsigned(d, DD)
 Next
 
 if stype=32 then
    MD5 = LCase(WordToHex(a) & WordToHex(b) & WordToHex(c) & WordToHex(d))
 else
    MD5=LCase(WordToHex(b) & WordToHex(c))  ´I crop this to fit 16byte database password :D
 end if
End Function
%>