clsmd5.cls

对文件的加密解密

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
  Persistable = 0  'NotPersistable
  DataBindingBehavior = 0  'vbNone
  DataSourceBehavior  = 0  'vbNone
  MTSTransactionMode  = 0  'NotAnMTSObject
END
Attribute VB_Name = "clsMD5"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit

' Visual Basic MD5 Implementation
' Robert Hubley and David Midkiff ([e-mail])
'
' Standard MD5 implementation optimised for the Visual Basic environment.
' Conforms to all standards and can be used in digital signature or password
' protection related schemes.

Private Const OFFSET_4 = 4294967296#
Private Const MAXINT_4 = 2147483647
Private State(4) As Long
Private ByteCounter As Long
Private ByteBuffer(63) As Byte
Private Const S11 = 7
Private Const S12 = 12
Private Const S13 = 17
Private Const S14 = 22
Private Const S21 = 5
Private Const S22 = 9
Private Const S23 = 14
Private Const S24 = 20
Private Const S31 = 4
Private Const S32 = 11
Private Const S33 = 16
Private Const S34 = 23
Private Const S41 = 6
Private Const S42 = 10
Private Const S43 = 15
Private Const S44 = 21

Property Get RegisterA() As String

    RegisterA = State(1)

End Property

Property Get RegisterB() As String

    RegisterB = State(2)

End Property

Property Get RegisterC() As String

    RegisterC = State(3)

End Property

Property Get RegisterD() As String

    RegisterD = State(4)

End Property

Public Function DigestStrToHexStr(SourceString As String) As String

    MD5Init
    MD5Update Len(SourceString), StringToArray(SourceString)
    MD5Final
    DigestStrToHexStr = GetValues

End Function

Public Function DigestByteToHexStr(Source() As Byte) As String

  Dim i As Long
  Dim j As Long
  Dim byteLen As Long

    MD5Init
    byteLen = UBound(Source)
    For i = 0 To Int(byteLen \ 64) - 1
        For j = 0 To 63
            ByteBuffer(j) = Source(i * 64 + j)
        Next j
        MD5Transform ByteBuffer()
    Next i
    i = byteLen Mod 64
    If i > 0 Then
        For j = 0 To i
            ByteBuffer(j) = Source(byteLen - i + j)
        Next j
        MD5Transform ByteBuffer()
    End If
    
    MD5Final
    DigestByteToHexStr = GetValues

End Function

Public Function DigestFileToHexStr(InFile As String) As String

    On Error GoTo errorhandler
    GoSub begin

errorhandler:
    DigestFileToHexStr = ""

Exit Function
    
begin:
  Dim FileO As Integer
    FileO = FreeFile
    Call FileLen(InFile)
    Open InFile For Binary Access Read As #FileO
    MD5Init
    Do While Not EOF(FileO)
        Get #FileO, , ByteBuffer
        If Loc(FileO) < LOF(FileO) Then
            ByteCounter = ByteCounter + 64
            MD5Transform ByteBuffer
        End If
    Loop
    ByteCounter = ByteCounter + (LOF(FileO) Mod 64)
    Close #FileO
    MD5Final
    DigestFileToHexStr = GetValues

End Function

Private Function StringToArray(InString As String) As Byte()

  Dim i As Integer, bytBuffer() As Byte

    ReDim bytBuffer(Len(InString))
    For i = 0 To Len(InString) - 1
        bytBuffer(i) = Asc(Mid$(InString, i + 1, 1))
    Next i
    StringToArray = bytBuffer

End Function

Public Function GetValues() As String

    GetValues = LongToString(State(3)) & LongToString(State(2)) & LongToString(State(4)) & LongToString(State(1))

End Function

Private Function LongToString(Num As Long) As String

  Dim A As Byte, B As Byte, C As Byte, D As Byte

    A = Num And &HFF&
    If A < 16 Then LongToString = "0" & Hex(A) Else LongToString = Hex(A)
    B = (Num And &HFF00&) \ 256
    If B < 16 Then LongToString = LongToString & "0" & Hex(B) Else LongToString = LongToString & Hex(B)
    C = (Num And &HFF0000) \ 65536
    If C < 16 Then LongToString = LongToString & "0" & Hex(C) Else LongToString = LongToString & Hex(C)
    If Num < 0 Then D = ((Num And &H7F000000) \ 16777216) Or &H80& Else D = (Num And &HFF000000) \ 16777216
    If D < 16 Then LongToString = LongToString & "0" & Hex(D) Else LongToString = LongToString & Hex(D)

End Function

Public Sub MD5Init()

    ByteCounter = 0
    State(1) = UnsignedToLong(1258584193#)
    State(2) = UnsignedToLong(4023654417#)
    State(3) = UnsignedToLong(2562699102#)
    State(4) = UnsignedToLong(2716285878#)

End Sub

Public Sub MD5Final()

  Dim dblBits As Double, padding(72) As Byte, lngBytesBuffered As Long

    padding(0) = &H80
    dblBits = ByteCounter * 8
    lngBytesBuffered = ByteCounter Mod 64
    If lngBytesBuffered <= 56 Then MD5Update 56 - lngBytesBuffered, padding Else MD5Update 120 - ByteCounter, padding
    padding(0) = UnsignedToLong(dblBits) And &HFF&
    padding(1) = UnsignedToLong(dblBits) \ 256 And &HFF&
    padding(2) = UnsignedToLong(dblBits) \ 65536 And &HFF&
    padding(3) = UnsignedToLong(dblBits) \ 16777216 And &HFF&
    padding(4) = 0
    padding(5) = 0
    padding(6) = 0
    padding(7) = 0
    MD5Update 8, padding

End Sub

Public Sub MD5Update(InputLen As Long, InputBuffer() As Byte)

  Dim II As Integer, i As Integer, j As Integer, K As Integer, lngBufferedBytes As Long, lngBufferRemaining As Long, lngRem As Long

    lngBufferedBytes = ByteCounter Mod 64
    lngBufferRemaining = 64 - lngBufferedBytes
    ByteCounter = ByteCounter + InputLen

    If InputLen >= lngBufferRemaining Then
        For II = 0 To lngBufferRemaining - 1
            ByteBuffer(lngBufferedBytes + II) = InputBuffer(II)
        Next II
        MD5Transform ByteBuffer
        lngRem = (InputLen) Mod 64
        For i = lngBufferRemaining To InputLen - II - lngRem Step 64
            For j = 0 To 63
                ByteBuffer(j) = InputBuffer(i + j)
            Next j
            MD5Transform ByteBuffer
        Next i
        lngBufferedBytes = 0
      Else
        i = 0
    End If
    For K = 0 To InputLen - i - 1
        ByteBuffer(lngBufferedBytes + K) = InputBuffer(i + K)
    Next K

End Sub

Private Sub MD5Transform(Buffer() As Byte)

  Dim X(16) As Long, A As Long, B As Long, C As Long, D As Long
    
    A = State(1)
    B = State(2)
    C = State(3)
    D = State(4)
    Decode 64, X, Buffer
    FF A, B, C, D, X(0), S11, -680876936
    FF D, A, B, C, X(1), S12, -389564586
    FF C, D, A, B, X(2), S13, 606105819
    FF B, C, D, A, X(3), S14, -1044525330
    FF A, B, C, D, X(4), S11, -176418897
    FF D, A, B, C, X(5), S12, 1200080426
    FF C, D, A, B, X(6), S13, -1473231341
    FF B, C, D, A, X(7), S14, -45705983
    FF A, B, C, D, X(8), S11, 1770035416
    FF D, A, B, C, X(9), S12, -1958414417
    FF C, D, A, B, X(10), S13, -42063
    FF B, C, D, A, X(11), S14, -1990404162
    FF A, B, C, D, X(12), S11, 1804603682
    FF D, A, B, C, X(13), S12, -40341101
    FF C, D, A, B, X(14), S13, -1502002290
    FF B, C, D, A, X(15), S14, 1236535329

    GG A, B, C, D, X(1), S21, -165796510
    GG D, A, B, C, X(6), S22, -1069501632
    GG C, D, A, B, X(11), S23, 643717713
    GG B, C, D, A, X(0), S24, -373897302
    GG A, B, C, D, X(5), S21, -701558691
    GG D, A, B, C, X(10), S22, 38016083
    GG C, D, A, B, X(15), S23, -660478335
    GG B, C, D, A, X(4), S24, -405537848
    GG A, B, C, D, X(9), S21, 568446438
    GG D, A, B, C, X(14), S22, -1019803690
    GG C, D, A, B, X(3), S23, -187363961
    GG B, C, D, A, X(8), S24, 1163531501
    GG A, B, C, D, X(13), S21, -1444681467
    GG D, A, B, C, X(2), S22, -51403784
    GG C, D, A, B, X(7), S23, 1735328473
    GG B, C, D, A, X(12), S24, -1926607734

    HH A, B, C, D, X(5), S31, -378558
    HH D, A, B, C, X(8), S32, -2022574463
    HH C, D, A, B, X(11), S33, 1839030562
    HH B, C, D, A, X(14), S34, -35309556
    HH A, B, C, D, X(1), S31, -1530992060
    HH D, A, B, C, X(4), S32, 1272893353
    HH C, D, A, B, X(7), S33, -155497632
    HH B, C, D, A, X(10), S34, -1094730640
    HH A, B, C, D, X(13), S31, 681279174
    HH D, A, B, C, X(0), S32, -358537222
    HH C, D, A, B, X(3), S33, -722521979
    HH B, C, D, A, X(6), S34, 76029189
    HH A, B, C, D, X(9), S31, -640364487
    HH D, A, B, C, X(12), S32, -421815835
    HH C, D, A, B, X(15), S33, 530742520
    HH B, C, D, A, X(2), S34, -995338651

    II A, B, C, D, X(0), S41, -198630844
    II D, A, B, C, X(7), S42, 1126891415
    II C, D, A, B, X(14), S43, -1416354905
    II B, C, D, A, X(5), S44, -57434055
    II A, B, C, D, X(12), S41, 1700485571
    II D, A, B, C, X(3), S42, -1894986606
    II C, D, A, B, X(10), S43, -1051523
    II B, C, D, A, X(1), S44, -2054922799
    II A, B, C, D, X(8), S41, 1873313359
    II D, A, B, C, X(15), S42, -30611744
    II C, D, A, B, X(6), S43, -1560198380
    II B, C, D, A, X(13), S44, 1309151649
    II A, B, C, D, X(4), S41, -145523070
    II D, A, B, C, X(11), S42, -1120210379
    II C, D, A, B, X(2), S43, 718787259
    II B, C, D, A, X(9), S44, -343485551

    State(1) = LongOverflowAdd(State(1), A)
    State(2) = LongOverflowAdd(State(2), B)
    State(3) = LongOverflowAdd(State(3), C)
    State(4) = LongOverflowAdd(State(4), D)

End Sub

Private Sub Decode(Length As Integer, OutputBuffer() As Long, InputBuffer() As Byte)

  Dim intDblIndex As Integer, intByteIndex As Integer, dblSum As Double

    For intByteIndex = 0 To Length - 1 Step 4
        dblSum = InputBuffer(intByteIndex) + InputBuffer(intByteIndex + 1) * 256# + InputBuffer(intByteIndex + 2) * 65536# + InputBuffer(intByteIndex + 3) * 16777216#
        OutputBuffer(intDblIndex) = UnsignedToLong(dblSum)
        intDblIndex = intDblIndex + 1
    Next intByteIndex

End Sub

Private Function FF(A As Long, B As Long, C As Long, D As Long, X As Long, S As Long, ac As Long) As Long

    A = LongOverflowAdd4(A, (B And C) Or (Not (B) And D), X, ac)
    A = LongLeftRotate(A, S)
    A = LongOverflowAdd(A, B)

End Function

Private Function GG(A As Long, B As Long, C As Long, D As Long, X As Long, S As Long, ac As Long) As Long

    A = LongOverflowAdd4(A, (B And D) Or (C And Not (D)), X, ac)
    A = LongLeftRotate(A, S)
    A = LongOverflowAdd(A, B)

End Function

Private Function HH(A As Long, B As Long, C As Long, D As Long, X As Long, S As Long, ac As Long) As Long

    A = LongOverflowAdd4(A, B Xor C Xor D, X, ac)
    A = LongLeftRotate(A, S)
    A = LongOverflowAdd(A, B)

End Function

Private Function II(A As Long, B As Long, C As Long, D As Long, X As Long, S As Long, ac As Long) As Long

    A = LongOverflowAdd4(A, C Xor (B Or Not (D)), X, ac)
    A = LongLeftRotate(A, S)
    A = LongOverflowAdd(A, B)

End Function

Function LongLeftRotate(value As Long, Bits As Long) As Long

  Dim lngSign As Long, lngI As Long

    Bits = Bits Mod 32
    If Bits = 0 Then LongLeftRotate = value: Exit Function
    For lngI = 1 To Bits
        lngSign = value And &HC0000000
        value = (value And &H3FFFFFFF) * 2
        value = value Or ((lngSign < 0) And 1) Or (CBool(lngSign And &H40000000) And &H80000000)
    Next lngI
    LongLeftRotate = value

End Function

Private Function LongOverflowAdd(Val1 As Long, Val2 As Long) As Long

  Dim lngHighWord As Long, lngLowWord As Long, lngOverflow As Long

    lngLowWord = (Val1 And &HFFFF&) + (Val2 And &HFFFF&)
    lngOverflow = lngLowWord \ 65536
    lngHighWord = (((Val1 And &HFFFF0000) \ 65536) + ((Val2 And &HFFFF0000) \ 65536) + lngOverflow) And &HFFFF&
    LongOverflowAdd = UnsignedToLong((lngHighWord * 65536#) + (lngLowWord And &HFFFF&))

End Function

Private Function LongOverflowAdd4(Val1 As Long, Val2 As Long, val3 As Long, val4 As Long) As Long

  Dim lngHighWord As Long, lngLowWord As Long, lngOverflow As Long

    lngLowWord = (Val1 And &HFFFF&) + (Val2 And &HFFFF&) + (val3 And &HFFFF&) + (val4 And &HFFFF&)
    lngOverflow = lngLowWord \ 65536
    lngHighWord = (((Val1 And &HFFFF0000) \ 65536) + ((Val2 And &HFFFF0000) \ 65536) + ((val3 And &HFFFF0000) \ 65536) + ((val4 And &HFFFF0000) \ 65536) + lngOverflow) And &HFFFF&
    LongOverflowAdd4 = UnsignedToLong((lngHighWord * 65536#) + (lngLowWord And &HFFFF&))

End Function

Private Function UnsignedToLong(value As Double) As Long

    If value < 0 Or value >= OFFSET_4 Then Error 6
    If value <= MAXINT_4 Then UnsignedToLong = value Else UnsignedToLong = value - OFFSET_4

End Function

Private Function LongToUnsigned(value As Long) As Double

    If value < 0 Then LongToUnsigned = value + OFFSET_4 Else LongToUnsigned = value

End Function