关于加密问题

[mili111]

怎样用vb对文本文件加密？？？？？？？？？？？？？？
（例如日记）

[rainstormmaster]

主题：一个简单实用的 vb 加密/解密算法

neil（原作）

关键字 VB 加密/解密 汉字加密

全部代码入下:

Function UserCode(password As String) As String
'用户口令加密
Dim il_bit, il_x, il_y, il_z, il_len, i As Long
Dim is_out As String
il_len = LenB(password)
il_x = 0
il_y = 0
is_out = ""
For i = 1 To il_len
il_bit = AscB(MidB(password, i, 1)) 'b系列支持中文

il_y = (il_bit * 13 Mod 256) + il_x
is_out = is_out & ChrB(Fix(il_y)) '取整 int和fix区别: fix修正负数
il_x = il_bit * 13 / 256
Next
is_out = is_out & ChrB(Fix(il_x))

password = is_out
il_len = LenB(password)
il_x = 0
il_y = 0
is_out = ""
For i = 1 To il_len
il_bit = AscB(MidB(password, i, 1))
'取前4位值
il_y = il_bit / 16 + 64
is_out = is_out & ChrB(Fix(il_y))
'取后4位值
il_y = (il_bit Mod 16) + 64
is_out = is_out & ChrB(Fix(il_y))
Next
UserCode = is_out
End Function


Function UserDeCode(password As String) As String
'口令解密
Dim is_out As String
Dim il_x, il_y, il_len, i, il_bit As Long

il_len = LenB(password)
il_x = 0
il_y = 0
is_out = ""
For i = 1 To il_len Step 2
il_bit = AscB(MidB(password, i, 1))
'取前4位值
il_y = (il_bit - 64) * 16
'取后4位值
'dd = AscW(Mid(password, i + 1, 1)) - 64
il_y = il_y + AscB(MidB(password, i + 1, 1)) - 64
is_out = is_out & ChrB(il_y)
Next

il_x = 0
il_y = 0
password = is_out
is_out = ""

il_len = LenB(password)
il_x = AscB(MidB(password, il_len, 1))
For i = (il_len - 1) To 1 Step -1
il_y = il_x * 256 + AscB(MidB(password, i, 1))
il_x = il_y Mod 13
is_out = ChrB(Fix(il_y / 13)) & is_out
Next
UserDeCode = is_out
End Function

[shawls]

[名称] MD5加密算法源代码

[语言种类] Visual Basic

[类别一] 算法

[类别二] 加解密

[类别三] 空

[数据来源] 未知

[保存时间] 2002-11-18

[关键字一] MD5

[关键字二] 加密/解密

[关键字三] 算法

[内容简介] 空

[源代码内容]

Option Explicit

Private Const OFFSET_4 = 4294967296#
Private Const MAXINT_4 = 2147483647

Private ByteCounter As Long
Private State(1 To 4) 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

'
' Function to digest a text string and output the result as a string
' of hexadecimal characters.
'
Public Function Encrypt(ByVal In_Data As String) As String
On Error GoTo EncryptErr

Encrypt = ""
MD5Init
MD5Update Len(In_Data), StringToArray(In_Data)
MD5Final
Encrypt = GetValues
Exit Sub

EncryptErr:
Encrypt = ""
Err.Raise vbObjectError + Err.Number, Err.Source, Err.Description
'Encrypt004Str = False

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
'
Private 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
'
Private Sub MD5Init()
ByteCounter = 0
State(1) = UnsignedToLong(1732584193#)
State(2) = UnsignedToLong(4023233417#)
State(3) = UnsignedToLong(2562383102#)
State(4) = UnsignedToLong(271733878#)
End Sub
'
' MD5 Final
'
Private 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

[shawls]

'
' Break up input stream into 64 byte chunks
'
Private 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
'
Private 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

[viena]

md5不可以吧，不可逆，用来加密密码还可以

[Blackstarhh]

加密是由你自己来定的，只要你确定了一个算法，你就可能在VB里实现，用别人想出来的东西怎是不安全和被动的。