Using cardano-wallet for ingame sign in

Question

i have built an in game User interface around Cardano-wallet. now im looking for a way to let the player sign in using his wallet .

how can i approach it using cardano-wallet? is there a way to let the player sign some data using his private key , then on the server side i decode it using his public key ?

( one of the solutions i tried is to let the player send 1 ADA from his wallet to a server provided address , and i monitor the transaction to verify ... but bad approach obviously ..)

thank you for your attention.

Answer 1

will wait for message sign / verify gets added to cardano-wallet api itself , https://github.com/input-output-hk/cardano-wallet/issues/3537 implementing it from scratch or doing other hacky ways will be inconvenient.

Answer 2

If your game is not browser based, one way to do this is to create a small website on which you let the user sign a message with a browser based wallet. The website can then send the signed message to your server.

To do this you can use the signData() method as specified in CIP-30.

Or if you have the private key of the user's wallet in your game, you can sign a message in your game and send it to the server.

On your server, you have to verify that the message is signed correctly. You can do this using the cardano-serialization-lib. More details on message signing can be found in CIP-8.

If the message is signed correctly, you can return something like an access token (e.g. a JWT) to the user.

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This is a very simple example on how this could work and there are a lot of things you'd need to consider when you implement this like franken-address attacks or token lifetimes etc.