# Writing a very simple encryption tool for a login

• ### Question

• Hello! I'm looking for a simple, easy, and very non-complicated way to encrypt a string.

Basically, I'm saving a 4-character PIN to an XML file and I'm wanting to just hide its true value while allowing a user to login using that PIN. Security is such a non-issue that I don't even have to encrypt the PIN, I'm just wanting to do it. So the easier the solution the better.

Imagine the user creates a PIN of '1234'. That PIN is saved in the XML file as <PIN>1234</PIN>.

When the user logs back in, I just need to be able to take their input and compare it against the value in <PIN>. If it matches, they're logged in.

Any recommendations?

Thanks!

Monday, February 18, 2019 9:11 PM

• If you're really not worried about making the encryption difficult to crack, the simplest way is to just add some number to the original and store the result as 5 digits. To decrypt, subtract the number and use the least significant four digits.

Example : Key (number to add/subtract) = 1010, PIN = 9876, encrypted number = 9876 + 1010 = 10886, decrypted = 10886 - 1010 = 9876

If your car radio stops working whenever you change the battery (as mine does), you will probably find the security code needed to re-activate it is written on the radio somewhere and encrypted something like the above.

• Marked as answer by Tuesday, February 19, 2019 4:38 AM
Monday, February 18, 2019 11:00 PM

### All replies

The solution should be using a database table. A XML file is not an optimal approach and not a secure one IMO. .

Monday, February 18, 2019 10:05 PM
• If you're really not worried about making the encryption difficult to crack, the simplest way is to just add some number to the original and store the result as 5 digits. To decrypt, subtract the number and use the least significant four digits.

Example : Key (number to add/subtract) = 1010, PIN = 9876, encrypted number = 9876 + 1010 = 10886, decrypted = 10886 - 1010 = 9876

If your car radio stops working whenever you change the battery (as mine does), you will probably find the security code needed to re-activate it is written on the radio somewhere and encrypted something like the above.

• Marked as answer by Tuesday, February 19, 2019 4:38 AM
Monday, February 18, 2019 11:00 PM

{
return Convert.ToBase64String(bytes); //protectedBytes
}