In short it's Ethereum Wallet to OpenID Connect bridge.
This means that any software that implements OpenID Connect authentication mechanism is able to use Cryptoauth.io as so called Identity Provider and login users that have Ethereum Wallet without requiring anyone to create any accounts or register anywhere.
You problably know those buttons "Login with Facebook" or "Signin with Google". It's the same thing. In both cases the process of validating the the user is really the user he/she is claiming to be is outsourced to external party (Facebook or Google in those cases). With Cryptoauth.io you are albe to do the same, the difference is that Cryptoauth.io validates that you are the owner of certain Ethereum address and tells the site that yes you really hold private keys to this address and that the site should use this address as your identity instead of your personal info.
You might ask how the site owner will reach you if the only information they receive is your Ethereum address? ETHMail to the rescue. By default Cryptoauth also passes your dedicated ethmail address that only owner od given address can use. Those emails have a form of [email protected]
The main reason to use Cryptoauth on your services is tha ability to login with any Ethereum Wallet (hardware wallets are supported through eg. Metamask).
Allowing anyone with Ethereum Wallet to login to your site might not be what you want exactly. While you want to give users of your dapp ability to interact with each other using only their addresses you also want to support only those users that really belong to your comunity.
You can do that with Token filtering build in Cryptoauth. You can specify one or many token with various conditions/tests and only people passing those tests will be able to login to your service.
Right now Cryptoauth supports only balanceOf function of any contract from eEthereum Mainnet. If you want to use other functions please let me know, I should be able to expand supported functions easily in most cases. Support for testchains should also be easy enough so let me know if you have use for such feature.
See our Pricing page
You can find support chat at https://chat.cryptoauth.io/.
You can send suggestions/questions to [email protected]