怎么加密和解密sqlite数据库

加密一个未加密的数据库或者更改一个加密数据库的密码,打开数据库，启动SQLiteConnection的ChangePassword() 函数

// Opens an unencrypted database

SQLiteConnection cnn = newSQLiteConnection("Data Source=c:\\test.db3")

cnn.Open()

// Encrypts the database. The connection remains valid and usable afterwards.

cnn.ChangePassword("mypassword")

解密一个已加密的数据库调用l ChangePassword() 将参数设为 NULL or "" :

// Opens an encrypted database

SQLiteConnection cnn = newSQLiteConnection("Data Source=c:\\test.db3Password=mypassword")

cnn.Open()

// Removes the encryption on an encrypted database.

cnn.ChangePassword("")

要打开一个已加密的数据库或者新建一个加密数据库，在打开或者新建前调用SetPassword（）函数

// Opens an encrypted database by calling SetPassword()

SQLiteConnection cnn = newSQLiteConnection("Data Source=c:\\test.db3")

cnn.SetPassword(newbyte[] { 0xFF, 0xEE, 0xDD, 0x10, 0x20, 0x30 })

cnn.Open()

// The connection is now usable

Sqlite数据库的加密

1、创建空的sqlite数据库。

//数据库名的后缀你可以直接指定，甚至没有后缀都可以

//方法一：创建一个空sqlite数据库，用IO的方式

FileStream fs = File.Create(“c:\\test.db“)

//方法二：用SQLiteConnection

SQLiteConnection.CreateFile(“c:\\test.db“)

创建的数据库是个0字节的文件。

2、创建加密的空sqlite数据库

//创建一个密码为password的空的sqlite数据库

SQLiteConnection.CreateFile（“c:\\test2.db“)

SQLiteConnection cnn = new SQLiteConnection(“Data Source=c:\\test2.db“)

SQLiteConnection cnn = new SQLiteConnection(“Data Source=D:\\test2.db“)

cnn.Open()

cnn.ChangePassword(“password“)

3、给未加密的数据库加密

SQLiteConnection cnn = new SQLiteConnection(“Data Source=c:\\test.db“)

cnn.Open()

cnn.ChangePassword(“password“)

4、打开加密sqlite数据库

//方法一

SQLiteConnection cnn = new SQLiteConnection(“Data Source=c:\\test2.db“)

cnn.SetPassword(“password“)

cnn.Open()

//方法二

SQLiteConnectionStringBuilder builder = new SQLiteConnectionStringBuilder()

builder.DataSource = @”c:\test.db“

builder.Password = @”password“

SQLiteConnection cnn = new SQLiteConnection(builder.ConnectionString)

cnn .Open()

分页

select * from messages limit 10,100

表示跳过10行，取100行的返回结果。

加密有很多中，常用的有MD5

C# md5加密（上）

string a//加密前数据

string b//加密后数据

b=System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(a,"MD5")

using System

using System.Security.Cryptography

方法2

public static string GetMD5(string myString)

{

MD5 md5 = new MD5CryptoServiceProvider()

byte[] fromData = System.Text.Encoding.Unicode.GetBytes(myString)

byte[] targetData = md5.ComputeHash(fromData)

string byte2String = null

for (int i=0 i<targetData.Length i++)

{

byte2String += targetData[i].ToString("x")

}

return byte2String

}

using System.Security.Cryptography

/// <summary>

/// 给一个字符串进行MD5加密

/// </summary>

/// <param name="strText">待加密字符串</param>

/// <returns>加密后的字符串</returns>

public static string MD5Encrypt(string strText)

{

MD5 md5 = new MD5CryptoServiceProvider()

byte[] result = md5.ComputeHash(System.Text.Encoding.Default.GetBytes(strText))

return System.Text.Encoding.Default.GetString(result)

}

C# MD5加密

using System.Security.Cryptography

private void btnOK_Click(object sender, System.EventArgs e)

{

string strConn = "server=192.168.0.51database=chenghengUser id=sapassword=123"

if(texName.Text.Trim()=="")

{

this.RegisterStartupScript("sf","<script language='javascript'>alert('用户名不能为空')document.all('texName').focus()</script>")

return

}

else if(texPassword.Text.Trim()=="")

{

this.RegisterStartupScript("sfs","<script language='javascript'>alert('密码不能为空')document.all('texPassword').focus()</script>")

return

}

else

{

//将获取的密码加密与数据库中加了密的密码相比较

byte[] by = md5.ComputeHash(utf.GetBytes(texPassword.Text.Trim()))

string resultPass = System.Text.UTF8Encoding.Unicode.GetString(by)

conn.ConnectionString=strConn

SqlCommand comm = new SqlCommand()

string name = texName.Text.Trim().ToString()

comm.CommandText="select Ruser_pwd,Ruser_nm from Ruser where Accountno = @name"

comm.Parameters.Add("@name",SqlDbType.NVarChar,40)

comm.Parameters["@name"].Value=name

try

{

conn.Open()

comm.Connection=conn

SqlDataReader dr=comm.ExecuteReader()

if(dr.Read())

{

//用户存在，对密码进行检查

if(dr.GetValue(0).Equals(resultPass))

{

string user_name=dr.GetValue(1).ToString()

string user_Accountno=texName.Text.Trim()

Session["logon_name"]=user_name

Session["logon_Accountno"]=user_Accountno

//登录成功，进行页面导向

}

else

{

this.RegisterStartupScript("wp","<script language='javascript'>alert('密码错误，请检查。')</script>")

}

}

else

{

this.RegisterStartupScript("nu","<script language=javascript>alert('用户名不存在，请检查。')</script>")

}

}

catch(Exception exec)

{

this.RegisterStartupScript("wc","<script language=javascript>alert('网络连接有异，请稍后重试。')</script>")

}

finally

{

conn.Close()

}

}

}

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