how to sign in if the password is stored in encrpted format in sql server

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SQL-Server-2005

This is my signup code, i have used md5 to hash the password. what is the code of sign-in button?

C#

private void button5_Click(object sender, EventArgs e)
       {
           SqlConnection myconnection;
           SqlCommand mycommand;
           int ra;
           string query;
            Byte[] hashedDataBytes;
           myconnection = new SqlConnection("Data Source=AMEERA-PC\\SQLEXPRESS;Initial Catalog=dbbaas;User ID=baas1;Password=baas123");
           myconnection.Open();
           MD5CryptoServiceProvider md5hasher = new MD5CryptoServiceProvider();

           UTF8Encoding encoder = new UTF8Encoding();
           hashedDataBytes = md5hasher.ComputeHash(encoder.GetBytes(textBox3.Text));
           StringBuilder hex = new StringBuilder(hashedDataBytes.Length * 2);
           foreach (Byte b in hashedDataBytes)
           {
               hex.AppendFormat("{0:x2}", b);
           }
           label3.Text = hex.ToString();


           query = "Insert into nuser ( uid,uname,enpwd) values(" + textBox1.Text + ",'" +
           textBox2.Text + "','" + hex.ToString() + "')";
           mycommand = new SqlCommand(query, myconnection);
           ra = mycommand.ExecuteNonQuery();

           if (ra > 0)
           {
               MessageBox.Show("Record Inserted Sucessfuly");
           }
           else
           {
               MessageBox.Show("Unable to Insert Record ");
           }
           myconnection.Close();


       }

please help , i need the code today?
thanks in advance

Posted 27-Dec-11 17:56pm

al-aml

Updated 27-Dec-11 18:02pm

coded007

v2

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Amir Mahfoozi 28-Dec-11 0:09am

read my answer here : http://www.codeproject.com/Answers/280703/store-procedure-example#answer4

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Sarvesh Kumar Gupta · Answer 1 · 2011-12-27T18:06:00

Solution 1

Hi, At the time of login, first encrypt entered password in textbox and compare this with database and check authenticate or not.

Posted 27-Dec-11 18:06pm

Sarvesh Kumar Gupta

coded007 · Answer 2 · 2011-12-27T18:08:00

Hi, you need to again write following code in login button

C#

hashedDataBytes = md5hasher.ComputeHash(encoder.GetBytes(textBox3.Text));
            StringBuilder hex = new StringBuilder(hashedDataBytes.Length * 2);
            foreach (Byte b in hashedDataBytes)
            {
                hex.AppendFormat("{0:x2}", b);
            }
            label3.Text = hex.ToString();
 

            query = "Select * from nuser  where uname='" + textBox1.Text + "' and enpwd ='" + hex.ToString() + "')";
            mycommand = new SqlCommand(query, myconnection);
            ra = mycommand.ExecuteNonQuery();

Manish.Insan · Answer 3 · 2011-12-27T18:09:00

Hello friend,

when you are retrieving data (password) back from database then decrypt that and compare. And i did this using UTF8 and decoded back :

like this :

C#

public string DecryptString(string pwd)
        {
          try
          {
            UTF8Encoding encoder = new System.Text.UTF8Encoding();
            Decoder utf8Decode = encoder.GetDecoder();

            byte[] toDecode_byte = Convert.FromBase64String(pwd);
            int charCount = utf8Decode.GetCharCount(toDecode_byte, 0, toDecode_byte.Length);
            char[] decoded_char = new char[charCount];
            utf8Decode.GetChars(toDecode_byte, 0, toDecode_byte.Length, decoded_char, 0);
            string decodedPwd = new string(decoded_char);
            return decodedPwd;
          }
          catch
          {
            return null;
          }
        }

Hope this will help you.
Don't forget to mark as answer if it helps. :)

santhosh-padamatinti · Answer 4 · 2011-12-27T18:24:00

XML

while sign in you need to fetch the password based on the user entered user name.
<pre lang="c#">
Select * from nuser where uname='textbox1.text';
</pre>

<pre lang="c#">
        MD5CryptoServiceProvider md5hasher = new MD5CryptoServiceProvider();

        UTF8Encoding encoder = new UTF8Encoding();
        hashedDataBytes = md5hasher.ComputeHash(encoder.GetBytes(Password.Text));
        StringBuilder hex = new StringBuilder(hashedDataBytes.Length * 2);
        foreach (Byte b in hashedDataBytes)
        {
            hex.AppendFormat("{0:x2}", b);
        }
        //label3.Text = hex.ToString();

        if ( FromDatabasepwd == hex.ToString())
        {
            // correct password
        }
        else
        {
            // incorrect pwd
        }
</pre>

al-aml · Answer 5 · 2011-12-27T18:39:00

Solution 5

WHAT DO YOU MEAN BY THIS FromDatabasepwd?IT GENERATE ERROR[DOES NOT EXIST IN CURRENT COTEXT]

C#

if ( FromDatabasepwd == hex.ToString())
       {
           // correct password
       }

Posted 27-Dec-11 18:39pm

al-aml

how to sign in if the password is stored in encrpted format in sql server

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