c# - Password encryption/decryption code in .NET

Question

I want simple encryption and decryption of password in C#. How to save the password in encrypted format in database and retrieve as original format by decryption?

Answer 1

Here you go. I found it somewhere on the internet. Works well for me.

    /// <summary>
    /// Encrypts a given password and returns the encrypted data
    /// as a base64 string.
    /// </summary>
    /// <param name="plainText">An unencrypted string that needs
    /// to be secured.</param>
    /// <returns>A base64 encoded string that represents the encrypted
    /// binary data.
    /// </returns>
    /// <remarks>This solution is not really secure as we are
    /// keeping strings in memory. If runtime protection is essential,
    /// <see cref="SecureString"/> should be used.</remarks>
    /// <exception cref="ArgumentNullException">If <paramref name="plainText"/>
    /// is a null reference.</exception>
    public string Encrypt(string plainText)
    {
        if (plainText == null) throw new ArgumentNullException("plainText");

        //encrypt data
        var data = Encoding.Unicode.GetBytes(plainText);
        byte[] encrypted = ProtectedData.Protect(data, null, Scope);

        //return as base64 string
        return Convert.ToBase64String(encrypted);
    }

    /// <summary>
    /// Decrypts a given string.
    /// </summary>
    /// <param name="cipher">A base64 encoded string that was created
    /// through the <see cref="Encrypt(string)"/> or
    /// <see cref="Encrypt(SecureString)"/> extension methods.</param>
    /// <returns>The decrypted string.</returns>
    /// <remarks>Keep in mind that the decrypted string remains in memory
    /// and makes your application vulnerable per se. If runtime protection
    /// is essential, <see cref="SecureString"/> should be used.</remarks>
    /// <exception cref="ArgumentNullException">If <paramref name="cipher"/>
    /// is a null reference.</exception>
    public string Decrypt(string cipher)
    {
        if (cipher == null) throw new ArgumentNullException("cipher");

        //parse base64 string
        byte[] data = Convert.FromBase64String(cipher);

        //decrypt data
        byte[] decrypted = ProtectedData.Unprotect(data, null, Scope);
        return Encoding.Unicode.GetString(decrypted);
    }