The iButton is just a memory device.
It is an industrial standard.
Being a technical industrial standard, it is not as simple as writing to a consumer device like a USB stick.
Yes, you can read and write to an iButton.
To do so, you need 2 things.
1 Hardware ( well under $100 last time I looked ).
There are various styles, including some that are Windows / PC compatible.
2 Software ( free last time I looked )
Once you have the ability to read/write to an iButton, you then need to have a little info about the format of data needed to be written.
If you are concerned about losing both of your keys, get one copied.
Or if you like, get the hardware and software above, and simply read your iButton / key contents.
With that info stored you will be on solid ground in the future.
Michael
www.dgbint.com