Encrypt And Decrypt Value In ASP.NET Using C#

Here I am storing the values in database using LINQ queries as encrypted form.

We can encrypt or decrypt values using other algorithms.

But here, I am using SALT to encrypt and decrypt the values.

Step 1:

public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
{
byte[] encryptedBytes = null;
// Set your salt here, change it to meet your flavor:
byte[] saltBytes = passwordBytes;
// Example:
//saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
AES.Mode = CipherMode.CBC;
using (CryptoStream cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
cs.Close();
}
encryptedBytes = ms.ToArray();
}
}
return encryptedBytes;
}
public byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
{
try
{
byte[] decryptedBytes = null;
// Set your salt here to meet your flavor:
byte[] saltBytes = passwordBytes;
// Example:
//saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };
using (MemoryStream ms = new MemoryStream())
{
using (RijndaelManaged AES = new RijndaelManaged())
{
AES.KeySize = 256;
AES.BlockSize = 128;
var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
AES.Key = key.GetBytes(AES.KeySize / 8);
AES.IV = key.GetBytes(AES.BlockSize / 8);
//AES.Mode = CipherMode.CBC;
using (CryptoStream cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
//If(cs.Length = ""
cs.Close();
}
decryptedBytes = ms.ToArray();
}
}
return decryptedBytes;
}
catch (Exception Ex)
{
return null;
}
}
public string Encrypt(string text, string pwd)
{
byte[] originalBytes = Encoding.UTF8.GetBytes(text);
byte[] encryptedBytes = null;
byte[] passwordBytes = Encoding.UTF8.GetBytes(pwd);
// Hash the password with SHA256
passwordBytes = SHA256.Create().ComputeHash(passwordBytes);
// Getting the salt size
int saltSize = GetSaltSize(passwordBytes);
// Generating salt bytes
byte[] saltBytes = GetRandomBytes(saltSize);
// Appending salt bytes to original bytes
byte[] bytesToBeEncrypted = new byte[saltBytes.Length + originalBytes.Length];
for (int i = 0; i < saltBytes.Length; i++)
{
bytesToBeEncrypted[i] = saltBytes[i];
}
for (int i = 0; i < originalBytes.Length; i++)
{
bytesToBeEncrypted[i + saltBytes.Length] = originalBytes[i];
}
encryptedBytes = AES_Encrypt(bytesToBeEncrypted, passwordBytes);
return Convert.ToBase64String(encryptedBytes);
}
public string Decrypt(string decryptedText, string pwd)
{
byte[] bytesToBeDecrypted = Convert.FromBase64String(decryptedText);
byte[] passwordBytes = Encoding.UTF8.GetBytes(pwd);
// Hash the password with SHA256
passwordBytes = SHA256.Create().ComputeHash(passwordBytes);
byte[] decryptedBytes = AES_Decrypt(bytesToBeDecrypted, passwordBytes);
if (decryptedBytes != null)
{
// Getting the size of salt
int saltSize = GetSaltSize(passwordBytes);
// Removing salt bytes, retrieving original bytes
byte[] originalBytes = new byte[decryptedBytes.Length - saltSize];
for (int i = saltSize; i < decryptedBytes.Length; i++)
{
originalBytes[i - saltSize] = decryptedBytes[i];
}
return Encoding.UTF8.GetString(originalBytes);
}
else
{
return null;
}
}
private int GetSaltSize(byte[] passwordBytes)
{
var key = new Rfc2898DeriveBytes(passwordBytes, passwordBytes, 1000);
byte[] ba = key.GetBytes(2);
StringBuilder sb = new StringBuilder();
for (int i = 0; i < ba.Length; i++)
{
sb.Append(Convert.ToInt32(ba[i]).ToString());
}
int saltSize = 0;
string s = sb.ToString();
foreach (char c in s)
{
int intc = Convert.ToInt32(c.ToString());
saltSize = saltSize + intc;
}
return saltSize;
}
public byte[] GetRandomBytes(int length)
{
byte[] ba = new byte[length];
RNGCryptoServiceProvider.Create().GetBytes(ba);
return ba;
}
public bool Add(Movy movie)
{
demo.Movies.InsertOnSubmit(movie);
demo.SubmitChanges();
return true;
}

Step 2: Call that methods in .cs file.

public partial class Add: System.Web.UI.Page
{
/// <summary>
/// Linq To SQL : Connection object.
/// </summary>
DemoDataContext demo = new DemoDataContext();
protected void Page_Load(object sender, EventArgs e)
{
}
/// <summary>
/// Button submit click event : Storing value in database as encrypted form
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void btnSubmit_Click(object sender, EventArgs e) {
try {
if (txtName.Text != "")
{
var m = new Movy
{
MovieName = new SecurityClass().Encrypt(txtName.Text, txtName.Text),
};
new SecurityClass().Add(m);
lblMessgae.Text = "Submitted successfully.";
txtName.Text = "";
}
}
catch (Exception ex)
{
ex.Message.ToString();
}
}
protected void btnSearch_Click(object sender, EventArgs e) {
try {
if (txtSearchByName.Text != "")
{
var movienameEncrypted = new SecurityClass().Encrypt(txtName.Text, txtName.Text);
if (movienameEncrypted != null)
{
string movienameDecrypt = new SecurityClass().Decrypt(movienameEncrypted, txtSearchByName.Text);
if (movienameDecrypt != null)
{
var Details = (from m in demo.Movies where movienameDecrypt == txtSearchByName.Text select new
{
UserName = m.Id
})
.FirstOrDefault();
if (Details != null)
{
lblMessgae.Text = "Movie exist into the database.";
}
else
{
lblMessgae.Text = "Not exist.";
}
}
else
{
lblMessgae.Text = "Not exist.";
}
}
}
}
catch (Exception ex)
{
ex.Message.ToString();
}
}

Screen:

6 Comments

Join the conversation! Your thoughts help the community grow.

diego loaiza4y ago
Would you have an example but without using the salt as a parameter?
Former member10y ago
Thank Andrews, I'll Definitely Will Try. Thanks For The Suggestion :)
Christopher Andrews10y ago
Cheers to the article! I have been using a tool called Redfly beta and it has been more than useful and easy to use. I suggest that you try it out too on www.redfly.io
Vikas Joshi11y ago
Thank you Sir :)
Santhakumar Munuswamy11y ago
Welcome
Santhakumar Munuswamy11y ago
Nice Start