I am a programmer (NOT an elements developer to make it clear I am not impersonating anyone
)
and I know a bit about security, so basically there is no need to encode the saved decks. The only thing necessary is to check whether the file is correct (does not contain any SQL code for example), and check with the server if the player has the necessary cards.
There should obviously be no limit on the number of decks you can save. Most players will have 2, 3 maybe 5, but there are players who make decks against certain strategies, decks for fun, decks for certain events, saving deck with every change they make and so on.
The option to save decks as a text file that you have to save manually to your disc and paste back to load a deck would probably be very easy to implement, but has one disadvantage - no way to check if you are selling a card used in one of your decks.
I have one idea though - you could have one special deck (than can never be loaded, but can contain over 60 cards) that would contain a list of cards you do not want to sell. When saving any other deck you could specify that these cards should be added (if not already there) to that deck. Removing them would be done manually, card by card. This would also make possible to add a button to bazar - "sell all cards except the ones 'protected'"
This mechanism would allow us to have both decks that we want to protect from sale and ones (eg. some very old deck you keep only for sentiment reasons
) that you do not protect. Also some way to add cards manually would be nice to eg. add rares we do not use in any deck.