<%
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)

   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)

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

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

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

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

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

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

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

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

Private Sub II(a, b, c, d, x, s, ac)
   a = AddUnsigned(a, AddUnsigned(AddUnsigned(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

   lMessageLength = Len(sMessage)

   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
       lWordArray(lWordCount) = lWordArray(lWordCount) Or LShift(Asc(Mid(sMessage, lByteCount + 1, 1)), lBytePosition)
       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)
   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

   x = ConvertToWordArray(sMessage)

   a = &H67452301
   b = &HEFCDAB89
   c = &H98BADCFE
   d = &H10325476

   For k = 0 To UBound(x) Step 16
       AA = a
       BB = b
       CC = c
       DD = d

       FF a, b, c, d, x(k + 0), S11, &HD76AA478
       FF d, a, b, c, x(k + 1), S12, &HE8C7B756
       FF c, d, a, b, x(k + 2), S13, &H242070DB
       FF b, c, d, a, x(k + 3), S14, &HC1BDCEEE
       FF a, b, c, d, x(k + 4), S11, &HF57C0FAF
       FF d, a, b, c, x(k + 5), S12, &H4787C62A
       FF c, d, a, b, x(k + 6), S13, &HA8304613
       FF b, c, d, a, x(k + 7), S14, &HFD469501
       FF a, b, c, d, x(k + 8), S11, &H698098D8
       FF d, a, b, c, x(k + 9), S12, &H8B44F7AF
       FF c, d, a, b, x(k + 10), S13, &HFFFF5BB1
       FF b, c, d, a, x(k + 11), S14, &H895CD7BE
       FF a, b, c, d, x(k + 12), S11, &H6B901122
       FF d, a, b, c, x(k + 13), S12, &HFD987193
       FF c, d, a, b, x(k + 14), S13, &HA679438E
       FF b, c, d, a, x(k + 15), S14, &H49B40821

       GG a, b, c, d, x(k + 1), S21, &HF61E2562
       GG d, a, b, c, x(k + 6), S22, &HC040B340
       GG c, d, a, b, x(k + 11), S23, &H265E5A51
       GG b, c, d, a, x(k + 0), S24, &HE9B6C7AA
       GG a, b, c, d, x(k + 5), S21, &HD62F105D
       GG d, a, b, c, x(k + 10), S22, &H2441453
       GG c, d, a, b, x(k + 15), S23, &HD8A1E681
       GG b, c, d, a, x(k + 4), S24, &HE7D3FBC8
       GG a, b, c, d, x(k + 9), S21, &H21E1CDE6
       GG d, a, b, c, x(k + 14), S22, &HC33707D6
       GG c, d, a, b, x(k + 3), S23, &HF4D50D87
       GG b, c, d, a, x(k + 8), S24, &H455A14ED
       GG a, b, c, d, x(k + 13), S21, &HA9E3E905
       GG d, a, b, c, x(k + 2), S22, &HFCEFA3F8
       GG c, d, a, b, x(k + 7), S23, &H676F02D9
       GG b, c, d, a, x(k + 12), S24, &H8D2A4C8A

       HH a, b, c, d, x(k + 5), S31, &HFFFA3942
       HH d, a, b, c, x(k + 8), S32, &H8771F681
       HH c, d, a, b, x(k + 11), S33, &H6D9D6122
       HH b, c, d, a, x(k + 14), S34, &HFDE5380C
       HH a, b, c, d, x(k + 1), S31, &HA4BEEA44
       HH d, a, b, c, x(k + 4), S32, &H4BDECFA9
       HH c, d, a, b, x(k + 7), S33, &HF6BB4B60
       HH b, c, d, a, x(k + 10), S34, &HBEBFBC70
       HH a, b, c, d, x(k + 13), S31, &H289B7EC6
       HH d, a, b, c, x(k + 0), S32, &HEAA127FA
       HH c, d, a, b, x(k + 3), S33, &HD4EF3085
       HH b, c, d, a, x(k + 6), S34, &H4881D05
       HH a, b, c, d, x(k + 9), S31, &HD9D4D039
       HH d, a, b, c, x(k + 12), S32, &HE6DB99E5
       HH c, d, a, b, x(k + 15), S33, &H1FA27CF8
       HH b, c, d, a, x(k + 2), S34, &HC4AC5665

       II a, b, c, d, x(k + 0), S41, &HF4292244
       II d, a, b, c, x(k + 7), S42, &H432AFF97
       II c, d, a, b, x(k + 14), S43, &HAB9423A7
       II b, c, d, a, x(k + 5), S44, &HFC93A039
       II a, b, c, d, x(k + 12), S41, &H655B59C3
       II d, a, b, c, x(k + 3), S42, &H8F0CCC92
       II c, d, a, b, x(k + 10), S43, &HFFEFF47D
       II b, c, d, a, x(k + 1), S44, &H85845DD1
       II a, b, c, d, x(k + 8), S41, &H6FA87E4F
       II d, a, b, c, x(k + 15), S42, &HFE2CE6E0
       II c, d, a, b, x(k + 6), S43, &HA3014314
       II b, c, d, a, x(k + 13), S44, &H4E0811A1
       II a, b, c, d, x(k + 4), S41, &HF7537E82
       II d, a, b, c, x(k + 11), S42, &HBD3AF235
       II c, d, a, b, x(k + 2), S43, &H2AD7D2BB
       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

   MD5 = LCase(WordToHex(a) & WordToHex(b) & WordToHex(c) & WordToHex(d))
End Function
%>
<!--###################################################################-->

File test:
<!--###################################################################-->
<HTML>


<%
Dim sDigest

Response.Write("<FONT FACE='COURIER' SIZE=3>")

sDigest = md5("abc")
Response.Write("MD5('abc')<BR>")
Response.Write("Expected: 900150983cd24fb0d6963f7d28e17f72<BR>")
Response.Write("Actual:   " & sDigest & "<BR><BR>")

sDigest = md5("message digest")
Response.Write("MD5('message digest')<BR>")
Response.Write("Expected: f96b697d7cb7938d525a2f31aaf161d0<BR>")
Response.Write("Actual:   " & sDigest & "<BR><BR>")

Response.Write("</FONT>")
%>
</HTML>

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