VB或VC编译的DLL文件可以部分反编译嘛？

分类: 电脑/网络 >>程序设计 >>其他编程语言

问题描述:

MD5("DIONNELLE")

如题,如果程序中包含一个MD5加密的字符串来当作密码的话! 并编译成DLL文件!

请问通过反编译,或者跟踪等黑客技术,可以得到MD5加密方式嘛? (因为我有可能是其它的加密方式)?还有可以得到里面的常量参数"DIONNELLE"嘛?

如果都可以得到,那请问如果加个变量$PS="DIONNELLE",然后再MD5($PS)

呢?

我知道经过VB\BC等编译过的DLL文件,目前还不能完全反编译! 但是通过部分反编译或跟踪等黑客技术不知道能不能得到加密的参数字符常量等!???

希望能详细说明!谢谢!如果可以得到,有什么办法可以防止!?

解析:

"DIONNELLE" 为常量，所以会放在程序的某个地方，有一个地址。

md5(md5(md5("DIONNELLE")))这样子是没有什么作用的。

反汇编出来也是几个push和call而已，没有什么作用

VB\BC等编译过的DLL文件,目前还不能完全反编译

无论是exe还是dll都可以反汇编，即使静态不行，也可以动态调试。

破解反汇编就行 了，不一定要反编译。

可以得到字符串的话,有可能得到是MD5三次循环嘛?

根据call的调用地址，绝对可以看出你是对同一个函数的三次调用。

至于看出你是否采用的是md5算法。这是根据代码的特征分析的。

如果要防止破解，最好给程序加上自己写的强壳，技术有很多我也说不了

，我也是略知一二而已，就不多说了。

以下是MD5代码，将其粘贴到模块中

Option Explicit

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

Private State(4) As Long

Private ByteCounter As Long

Private ByteBuffer(63) As Byte

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 GetMD5(ByVal str As String) As String

GetMD5 = DigestStrToHexStr(str)

End Function

'

' 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))

' 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 lng

'

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

Dim lngHighWord As Long

Dim lngLowWord As Long

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

IF pss <>GetMD5(Txtpassword) THEN

。。。。

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