1. Код на основе API функций библиотеки cryptdll.
Примечание: начиная с Vista эти функции продублированы в ntdll.dll (недокументированная возможность).
Код (vb.net):
Option Explicit
Private Type MD5_CTX
i(1 To 2) As Long
buf(1 To 4) As Long
inp(1 To 64) As Byte
digest(1 To 16) As Byte
End Type
Private Declare Sub MD5Init Lib "cryptdll" (Context As MD5_CTX)
Private Declare Sub MD5Update Lib "cryptdll" (Context As MD5_CTX, ByVal strInput As String, ByVal lLen As Long)
Private Declare Sub MD5Final Lib "cryptdll" (Context As MD5_CTX)
Private Sub Command1_Click()
MsgBox CalcMD5("C:\Win32_BIOS.txt")
MsgBox CalcMD5_String("C:\Win32_BIOS.txt")
End Sub
Private Function CalcMD5_String(strBuffer As String) As String
Dim myContext As MD5_CTX
Dim result As String
Dim lp As Long
Dim MD5 As String
MD5Init myContext
MD5Update myContext, strBuffer, Len(strBuffer)
MD5Final myContext
result = StrConv(myContext.digest, vbUnicode)
For lp = 1 To Len(result)
CalcMD5_String = CalcMD5_String & Right("00" & Hex(Asc(Mid(result, lp, 1))), 2)
Next
End Function
Private Function CalcMD5(strFilename As String) As String
Dim strBuffer As String
Dim myContext As MD5_CTX
Dim result As String
Dim lp As Long
Dim MD5 As String
strBuffer = Space(FileLen(strFilename))
Open strFilename For Binary Access Read As #1
Get #1, , strBuffer
Close #1
MD5Init myContext
MD5Update myContext, strBuffer, Len(strBuffer)
MD5Final myContext
result = StrConv(myContext.digest, vbUnicode)
For lp = 1 To Len(result)
CalcMD5 = CalcMD5 & Right("00" & Hex(Asc(Mid(result, lp, 1))), 2)
Next
End Function
2. Чисто математическая реализация. Автор: Robert Hubley
Код (vb.net):
VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
Persistable = 0 'NotPersistable
DataBindingBehavior = 0 'vbNone
DataSourceBehavior = 0 'vbNone
MTSTransactionMode = 0 'NotAnMTSObject
END
Attribute VB_Name = "MD5_Hash"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
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 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
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 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
