Access数据库的安全性研究及其应用

<%@ Import Namespace="System.Globalization" %>
<script Language="VB" Runat="Server">
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Function Encrypt(s As String) As String  '加密入口函数
    Dim rnd As Random
    Dim Seed As Integer
    Seed = RandomSeed()
    Encrypt = (Seed Xor AscW("数") Xor AscW("据")).ToString("X4")
    ' Encrypt为密钥，由随机种子和"数"、"据"的Unicode编码异或运算而成的
    rnd = new Random(Seed)
    Encrypt += RandomEncrypt(s,rnd)
End Function
Function RandomSeed() AS Integer  '生成随机种子函数
    Dim rnd As Random
    rnd = new Random()
    Randomize (Timer)
    RandomSeed = rnd.Next And 32767
End Function
Function RandomEncrypt(s As String,rnd As Random) As String  '随机加密函数
    Dim n As Integer = 1
    RandomEncrypt = ""
    Do While n <= s.Length
        RandomEncrypt += ((rnd.Next And 65535) Xor 
        AscW(Mid(s,n,1))).ToString("X4")
        n += 1
    Loop
End Function

<%@ Import Namespace="System.Globalization" %>
<script Language="VB" Runat="Server">
Function Decrypt(s As String) As String  '解密函数
    Dim Seed,EncryptCode As Integer
    Dim DecryptChar As String
    Dim rnd As Random
    Seed = Int32.Parse(Mid$(s,1,4),NumberStyles.HexNumber)
    Seed = Seed Xor AscW("数") Xor AscW("据")
    rnd = new Random(Seed)
    Dim n  As Integer = 5
    Decrypt = ""
    Do While n < s.Length
        EncryptCode = Int32.Parse(Mid$(s,n,4),NumberStyles.HexNumber)
        DecryptChar = ChrW((rnd.Next And 65535) Xor EncryptCode)
        Decrypt += DecryptChar
        n += 4
    Loop
End Function

<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.OleDb" %>
<script Language="VB" Runat="Server">
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Dim a As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=DB1.MDB"
Dim pass As String = Encrypt("13039498050")  ' 调用Encrypt ()函数对数据进行加密
Dim MyExecuteQuery As String= "insert into 
Member([id],[name],[password]) 
Values(11,'Admin','" +pass +"')"
Dim MyConnection As New OleDbConnection(a)
Dim MyCommand As New OleDbCommand(MyExecuteQuery, MyConnection)
MyCommand.Connection.Open()
MyCommand.ExecuteNonQuery()
MyConnection.Close()

<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.OleDb" %>
<script Language="VB" Runat="Server">
…  …  …  …
Dim a As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= DB1.MDB"
Dim MyConnection As New OleDbConnection(a) 
Dim adapter As OleDbDataAdapter = New OleDbDataAdapter
("select * from Member", MyConnection)
Dim DS As DataSet= New DataSet()
adapter.Fill(DS,"Member")
DS.Tables("Member").Rows(0)("password")=Decrypt(DS.Tables
("Member").Rows(0)("password"))
'调用Decrypt()函数对password字段进行解密
Member.DataSource=DS.Tables("Member").DefaultView
Member.DataBind()
MyConnection.Close()
…  …  …  …
<form runat="server">
<ASP:DataGrid id="Member" runat="server" 
AutoGenerateColumns="false">
<columns>
<asp:BoundColumn HeaderText="ID" DataField="id"/>
<asp:BoundColumn HeaderText="Name" DataField="name"/>
<asp:BoundColumn HeaderText="Password" DataField="password"/>
</columns>
</ASP:DataGrid>
</form>