VB MD5算法函数的详细介绍
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
'= '= Class Properties '= Property Get RegisterA() As String RegisterA = State(1) End Property
Property Get RegisterB() As String
RegisterB = State(2) End PropertyProperty Get RegisterC() As String
RegisterC = State(3) End PropertyProperty 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 Open FileName For Binary Access Read As #1 MD5Init Do While Not EOF(1) Get #1, , ByteBuffer If Loc(1) < LOF(1) Then ByteCounter = ByteCounter + 64 MD5Transform ByteBuffer End If Loop ByteCounter = ByteCounter + (LOF(1) 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 MD5Update 56 - lngBytesBuffered, padding Else MD5Update 120 - ByteCounter, padding 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 - 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 ' 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 SubPrivate 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 FunctionPrivate 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 FunctionPrivate 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 FunctionPrivate 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 LonglngLowWord = (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 LonglngLowWord = (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'使用方法
'msgbox DigestStrToHexStr("111")