Encryption

Track/Stream: Brandston - King of Pain

I just threw a spiffy chunk of code in. There's a task which needs to be run from a command line (so we can do it manually or via a cron job). It uses the same transport mechanism as the rest of my communications, so to prevent a wayward developer from allowing unauthorized clients from running the job, it requires a username and password. However, the LAN guys don't want to put a password in plain text.

So in about 5 lines of code I implemented the ability to encrypt the password using RSA. The encrypted password may be fed in in place of the plain-text one. It auto-detects between encrypted and plain-text password and decrypts if necessary. The password is then sent to the server who authenticates it. As a bonus, if you tell it to encrypt, but don't give it text to encrypt, it dumps the encryption key.

      using System.Text;

      using System.Security.Cryptography;

      private const string ENCRYPTION_KEYS = 

        "<RSAKeyValue><Modulus>...</Modulus>" +

        "<Exponent>...</Exponent><P>...</P>" + 

        "<Q>...</Q><DP>...</DP><DQ>...</DQ>" +

        "<InverseQ>...</InverseQ><D>...</D></RSAKeyValue>";

      // Create and initializes our encryption/decryption

      RSACryptoServiceProvider Provider = 

        new RSACryptoServiceProvider();

      Provider.FromXmlString(ENCRYPTION_KEYS);

      if (Encrypting && (Password == null))

        // Dump Encryption Key

        System.Console.WriteLine(Provider.ToXmlString(false));

      else if (Encrypting)

        // Dump Encrypted Password

        System.Console.WriteLine(Convert.ToBase64String(

          Provider.Encrypt(

            Encoding.ASCII.GetBytes(args[1]), true)));

      else

        // Decrypt Password and Replace.  

        // If there's an error, user supplied plain text already

        try { Password = Encoding.ASCII.GetString(

          Provider.Decrypt(

            Convert.FromBase64String(args[2]), true)); }

        catch { }