รอแล้วไม่มีผู้รู้ช่วยตอบเลย งั้นขอรบกวน อธิบายโค๊ดอันนี้หน่อยนะคะ ตรง MD5
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Option Compare Database
Option Explicit
Public sMyServer As String, sMyUserID As String, sMyDatabase As String, sMyPassword As String, sFind As String, sPlateNo As String, isAddInvoice As Boolean

Public Type GUID
    Data1 As Long
    Data2 As Integer
    Data3 As Integer
    Data4(7) As Byte
End Type

Public Declare Function StringFromGUID2 Lib "ole32.dll" _
    (rclsid As GUID, ByVal lpsz As Long, ByVal cbMax As Long) As Long
Public Declare Function CoCreateGuid Lib "ole32.dll" _
    (rclsid As GUID) As Long

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) As Long
Private m_l2Power(30) As Long

Public Function StGuidFromGuid(rclsid As GUID) As String
    Dim rc As Long
    Dim stGuid As String

    ' 39 chars for the GUID plus room for the Null char
    stGuid = String$(40, vbNullChar)
    rc = StringFromGUID2(rclsid, StrPtr(stGuid), Len(stGuid) - 1)
    StGuidFromGuid = Left$(stGuid, rc - 1)
End Function

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
    
    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)

    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

มึนตึบเลยครับ ละลานตามากๆ
เท่าที่เคยรู้จัก เคยลองใช้มาบ้าง MD5 คือเทคโนโลยี การเข้ารหัสแบบทางเดียว ที่ผมเคยใช้ใน php
สงสัยนี่คงจะเป็นการนำมาเลียนแบบโดยเขียนออกมาในรูปแบบภาษา ตระกูล VB

เรื่องการเข้ารหัสนี่ โดยส่วนตัวแล้วผมเศษเสี้ยวของหางอึ่งจริงๆ ครับไม่รู้จะช่วยยังไง แต่ก็เข้ามา Reply เพื่อจะให้ได้รู้ว่า มีคนเข้าอ่านกระทู้นี้เหมือนกัน ครับ (และแอบรอสอยเอาความรู้ เมื่อมีคนเข้ามาอธิบายด้วย อิอิ)

น่าสนใจนะครับ

ผมว่า ต้องเข้าใจอัลกอรึธึมของ MD5 ก่อนว่ามันทำงานยังไง ตัวผมเองไม่มีความรู้รเื่องนี้ แต่พอค้นจาก Internet ก็พอหาได้บ้าง ลองไปอ่านดูนะครับ

http://www.beartai.com/webboard/index.php?topic=44590.0

http://en.wikipedia.org/wiki/MD5

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