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星落的瞬間!放棄的後悔是永遠!

引用自:http://bbs.wefong.com/viewthread.php?tid=1954539&extra=page%3D1
看到微風的一個好文, 但沒有格式太難看了,所以我幫忙改了一下,sorry喔~
據crabmarss說有原版有兩個錯誤,
1、對於檔案或字串大小在64n+56(n為含0的整數)時會產生計算錯誤
2、對於檔案大小在64倍數時,會少計算一段64節內容

Robert M. Hubley 12/1999原創

crabmarss 2009/04/14修改

 

Option Explicit '/******************************************************************************
' * Copyright (C) 2000 by Robert Hubley. *
' * All rights reserved. *
' * *
' * This software is provided ``AS IS'' and any express or implied *
' * warranties, including, but not limited to, the implied warranties of *
' * merchantability and fitness for a particular purpose, are disclaimed. *
' * In no event shall the authors be liable for any direct, indirect, *
' * incidental, special, exemplary, or consequential damages (including, but *
' * not limited to, procurement of substitute goods or services; loss of use, *
' * data, or profits; or business interruption) however caused and on any *
' * theory of liability, whether in contract, strict liability, or tort *
' * (including negligence or otherwise) arising in any way out of the use of *
' * this software, even if advised of the possibility of such damage. *
' * *
' ******************************************************************************
'
' CLASS: MD5
'
' DESCRIPTION:
' This is a class which encapsulates a set of MD5 Message Digest functions.
' MD5 algorithm produces a 128 bit digital fingerprint (signature) from an
' dataset of arbitrary length. For details see RFC 1321 (summarized below).
' This implementation is derived from the RSA Data Security, Inc. MD5 Message-Digest
' algorithm reference implementation (originally written in C)
'
' AUTHOR:
' Robert M. Hubley 12/1999
'
'
' NOTES:
' Network Working Group R. Rivest
' Request for Comments: 1321 MIT Laboratory for Computer Science
' and RSA Data Security, Inc.
' April 1992
'
'
' The MD5 Message-Digest Algorithm
'
' Summary
'
' This document describes the MD5 message-digest algorithm. The
' algorithm takes as input a message of arbitrary length and produces
' as output a 128-bit "fingerprint" or "message digest" of the input.
' It is conjectured that it is computationally infeasible to produce
' two messages having the same message digest, or to produce any
' message having a given prespecified target message digest. The MD5
' algorithm is intended for digital signature applications, where a
' large file must be "compressed" in a secure manner before being
' encrypted with a private (secret) key under a public-key cryptosystem
' such as RSA.
'
' The MD5 algorithm is designed to be quite fast on 32-bit machines. In
' addition, the MD5 algorithm does not require any large substitution
' tables; the algorithm can be coded quite compactly.
'
' The MD5 algorithm is an extension of the MD4 message-digest algorithm
' 1,2]. MD5 is slightly slower than MD4, but is more "conservative" in
' design. MD5 was designed because it was felt that MD4 was perhaps
' being adopted for use more quickly than justified by the existing
' critical review; because MD4 was designed to be exceptionally fast,
' it is "at the edge" in terms of risking successful cryptanalytic
' attack. MD5 backs off a bit, giving up a little in speed for a much
' greater likelihood of ultimate security. It incorporates some
' suggestions made by various reviewers, and contains additional
' optimizations. The MD5 algorithm is being placed in the public domain
' for review and possible adoption as a standard.
'
' RFC Author:
' Ronald L.Rivest
' Massachusetts Institute of Technology
' Laboratory for Computer Science
' NE43 -324545 Technology Square
' Cambridge, MA 02139-1986
' Phone: (617) 253-5880
' EMail: Rivest@ theory.lcs.mit.edu
'
'
'
' CHANGE HISTORY:
'
' 0.1.0 RMH 1999/12/29 Original version
'
'
'=
'= Class Constants
'=
Private Const OFFSET_4 = 4294967296# Private Const MAXINT_4 = 2147483647 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 '=
'= Class Variables
'=
Private State(4) As Long Private ByteCounter As Long Private ByteBuffer(63) As Byte Private DigestFileToHexStr_GetValues As String '=
'= Class Events
'=
Public Event GetFileSize(Fsize As Long) Public Event ReadFileGetValue(Value As Long) '=
'= Class Properties
'=
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 '=
'= Class Functions
'=
'
' Function to quickly digest a file into a hex string
'
Public Function DigestFileToHexStr(FileName As String) As String Dim Length As Long Open FileName For Binary Access Read As #1 MD5Init Length = LOF(1) ' Get length of file
Do While Not EOF(1) Get #1, , ByteBuffer If Loc(1) <= Length Then '修改處 ByteCounter = ByteCounter + 64 MD5Transform ByteBuffer End If Loop ByteCounter = ByteCounter + (Length Mod 64) Close #1 MD5Final DigestFileToHexStr = GetValues End Function '
' Function to digest a text string and output the result as a string
' of hexadecimal characters.
'
Public Function DigestStrToHexStr(SourceString As String) As String MD5Init MD5Update Len(SourceString), StringToArray(SourceString) MD5Final DigestStrToHexStr = GetValues End Function '
' A utility function which converts a string into an array of
' bytes.
'
Private Function StringToArray(InString As String) As Byte() Dim i As Integer Dim 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 '
' Concatenate the four state vaules into one string
'
Public Function GetValues() As String GetValues = LongToString(State(1)) & LongToString(State(2)) & LongToString(State(3)) & LongToString(State(4)) End Function '
' Convert a Long to a Hex string
'
Private Function LongToString(Num As Long) As String Dim a As Byte Dim b As Byte Dim C As Byte Dim d As Byte a = Num And &HFF& If a < 16 Then LongToString = "0" & Hex(a) Else LongToString = Hex(a) End If b = (Num And &HFF00&) \ 256 If b < 16 Then LongToString = LongToString & "0" & Hex(b) Else LongToString = LongToString & Hex(b) End If C = (Num And &HFF0000) \ 65536 If C < 16 Then LongToString = LongToString & "0" & Hex(C) Else LongToString = LongToString & Hex(C) End If If Num < 0 Then d = ((Num And &H7F000000) \ 16777216) Or &H80& Else d = (Num And &HFF000000) \ 16777216 End If If d < 16 Then LongToString = LongToString & "0" & Hex(d) Else LongToString = LongToString & Hex(d) End If End Function '
' Initialize the class
' This must be called before a digest calculation is started
'
Public Sub MD5Init() ByteCounter = 0 State(1) = UnsignedToLong(1732584193#)
State(2) = UnsignedToLong(4023233417#)
State(3) = UnsignedToLong(2562383102#)
State(4) = UnsignedToLong(271733878#)
End Sub '
' MD5 Final
'
Public Sub MD5Final() Dim dblBits As Double Dim padding(72) As Byte Dim lngBytesBuffered As Long padding(0) = &H80 dblBits = ByteCounter * 8 ' Pad out
lngBytesBuffered = ByteCounter Mod 64 If lngBytesBuffered < 56 Then'修改處

MD5Update 56 - lngBytesBuffered, padding Else MD5Update 120 - lngBytesBuffered, padding '修改處
End If 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 '
' Break up input stream into 64 byte chunks
'
Public Sub MD5Update(InputLen As Long, InputBuffer() As Byte) Dim II As Integer Dim i As Integer Dim J As Integer Dim k As Integer Dim lngBufferedBytes As Long Dim lngBufferRemaining As Long Dim lngRem As Long lngBufferedBytes = ByteCounter Mod 64 lngBufferRemaining = 64 - lngBufferedBytes ByteCounter = ByteCounter + InputLen ' Use up old buffer results first
If InputLen >= lngBufferRemaining Then For II = 0 To lngBufferRemaining - 1 ByteBuffer(lngBufferedBytes + II) = InputBuffer(II) Next II MD5Transform ByteBuffer lngRem = (InputLen) Mod 64 ' The transfer is a multiple of 64 lets do some transformations

For i = lngBufferRemaining To InputLen - 64 Step 64 '修改處

For J = 0 To 63 ByteBuffer(J) = InputBuffer(i + J) Next J MD5Transform ByteBuffer Next i lngBufferedBytes = 0 Else i = 0 End If ' Buffer any remaining input
For k = 0 To InputLen - i - 1 ByteBuffer(lngBufferedBytes + k) = InputBuffer(i + k) Next k End Sub '
' MD5 Transform
'
Private Sub MD5Transform(Buffer() As Byte) Dim x(16) As Long Dim a As Long Dim b As Long Dim C As Long Dim d As Long a = State(1) b = State(2) C = State(3) d = State(4) Decode 64, x, Buffer ' Round 1
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 ' Round 2
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 ' Round 3
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 ' Round 4
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) ' /* Zeroize sensitive information.
'*/
' MD5_memset ((POINTER)x, 0, sizeof (x));

End Sub Private Sub Decode(Length As Integer, OutputBuffer() As Long, InputBuffer() As Byte) Dim intDblIndex As Integer Dim intByteIndex As Integer Dim dblSum As Double intDblIndex = 0 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 '
' FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
' Rotation is separate from addition to prevent recomputation.
'
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 '
' Rotate a long to the right
'
Function LongLeftRotate(Value As Long, bits As Long) As Long Dim lngSign As Long Dim 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 LongLeftRotate = Value End Function '
' Function to add two unsigned numbers together as in C.
' Overflows are ignored!
'
Private Function LongOverflowAdd(Val1 As Long, Val2 As Long) As Long Dim lngHighWord As Long Dim lngLowWord As Long Dim 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 '
' Function to add two unsigned numbers together as in C.
' Overflows are ignored!
'
Private Function LongOverflowAdd4(Val1 As Long, Val2 As Long, val3 As Long, val4 As Long) As Long Dim lngHighWord As Long Dim lngLowWord As Long Dim 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 '
' Convert an unsigned double into a long
'
Private Function UnsignedToLong(Value As Double) As Long If Value < 0 Or Value >= OFFSET_4 Then Error 6 ' Overflow
If Value <= MAXINT_4 Then UnsignedToLong = Value Else UnsignedToLong = Value - OFFSET_4 End If End Function '
' Convert a long to an unsigned Double
'
Private Function LongToUnsigned(Value As Long) As Double If Value < 0 Then LongToUnsigned = Value + OFFSET_4 Else LongToUnsigned = Value End If End Function
創作者介紹

!壞人必需做好事!

讓地獄深紅的天亮 發表在 痞客邦 PIXNET 留言(1) 人氣()


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  • dgnzj
  • 好文,受用了

    最近剛好需要這樣的文件,結果讓我找到你的文章
    結果解決了因為檔案大小產生的溢位錯誤
    感謝囉~
  • 請感謝crabmarss吧!他應該也是本著助人為快樂之本的心分享的。

    讓地獄深紅的天亮 於 2010/03/12 02:11 回覆

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