This is a proposal to integrate Sign in with Stacks (SIWS) in Leather. The goal of this proposal is to have a standardised way for apps to ask users to log in easily and increase the security of users when they use this login method (by verifying the domain in the message).
It's a port of SIWE (in the evm ecosystem) for Stacks and is commonly supported by various wallets.
There is a SIP proposal that describes the message format, as well as an npm package that can be used for integration.
I am creating this issue to start the discussion and see if there is interest for Leather to integrate this.

References:

• siwe: https://siwe.xyz/
• how metamask is handling this: https://docs.metamask.io/wallet/how-to/sign-data/siwe
• Stacks SIP: Sign-in with stacks stacksgov/sips#70
• Stacks npm package to handle messages: https://github.com/pradel/sign-in-with-stacks