'这是我从网上找到的一段加密解密的代码，很不错，应该符合要求。
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'文本框的multiline属性是用来设置是否可以接受多行文本，只能在窗体上手工设置。
'文本框的scrollbars属性是用来设置是否有垂直和水平滚动条的，也只能在窗体上手工设置。
'keyAscii不清楚是作什么用的。
'两个StrConv函数用的太好了，我没想到能处理的这么简单。
Option Explicit
Dim key() As Byte
Sub initkey() '这里为密匙，建议定义的复杂些，我这里仅仅是个示例
ReDim key(9)
key(0) = 12
key(1) = 43
key(2) = 53
key(3) = 67
key(4) = 78
key(5) = 82
key(6) = 91
key(7) = 245
key(8) = 218
key(9) = 190
End Sub
Function Pass_Encode(ByVal s As String) As String '加密
On Error GoTo myerr
initkey
Dim buff() As Byte
buff = StrConv(s, vbFromUnicode)
Dim i As Long, j As Long
Dim k As Long
k = UBound(key) + 1
For i = 0 To UBound(buff)
j = i Mod k
buff(i) = buff(i) Xor key(j)
Next
Dim mstr As String
mstr = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Dim outstr As String
Dim temps As String
For i = 0 To UBound(buff)
k = buff(i) \ Len(mstr)
j = buff(i) Mod Len(mstr)
temps = Mid(mstr, j + 1, 1) + Mid(mstr, k + 1, 1)
outstr = outstr + temps
Next
Pass_Encode = outstr
Exit Function
myerr:
Pass_Encode = ""
End Function
Function Pass_Decode(ByVal s As String) As String '解密
On Error GoTo myerr
initkey
Dim i As Long, j As Long
Dim k As Long, n As Long
Dim mstr As String
mstr = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Dim outstr As String
Dim temps As String
If Len(s) Mod 2 = 1 Then
Pass_Decode = ""
Exit Function
End If
Dim t1 As String
Dim t2 As String
Dim buff() As Byte
Dim m As Long
m = 0
For i = 1 To Len(s) Step 2
t1 = Mid(s, i, 1)
t2 = Mid(s, i + 1, 1)
j = InStr(1, mstr, t1)
k = InStr(1, mstr, t2)
n = j - 1 + (k - 1) * Len(mstr)
ReDim Preserve buff(m)
buff(m) = n
m = m + 1
Next
k = UBound(key) + 1
For i = 0 To UBound(buff)
j = i Mod k
buff(i) = buff(i) Xor key(j)
Next
Pass_Decode = StrConv(buff, vbUnicode)
Exit Function
myerr:
Pass_Decode = ""
End Function
Private Sub Command1_Click()
Text2.Text = Pass_Encode(Text1.Text)
Text3.Text = Pass_Decode(Text2.Text)
End Sub
Private Function myEncrypt(ByVal Code As String) As String
Dim Result As String = ""
Dim CurrentChar As Char
For i As Integer = 0 To Code.Length - 1
CurrentChar = Code.Substring(i, 1)
Select Case Code.Substring(i, 1)
Case "Z"
Result = "a"
Case "z"
Result = "A"
Case Else
Result = Chr(Asc(CurrentChar) + 1)
End Select
Next
Return Result
End Function
'vb.net 2005 调试通过
"采用DES算法"这个说法不明确，首先是使用多少位的DES进行加密，通常是128位或192位，其次是，要先把主密钥转化成散列，才能供DES进行加密，转化的方法是什么没有明确，通常是md5，所以有的银行卡说是128位md5 3DS就是指用md5转换主密钥散列，用DES进行加密，但是DES本身是64位（包含校验码），2DES是128位，3DES是192位，但是没有2DES的叫法，所以128位、192位统称3DES
要完整的md5+3DS实例，需要100分以上，要不到我的空间中查找相关的文章