[Why MoneroSSO]
MoneroSSO is primarily aimed at making spam attacks expensive for an adversary. If one has the intent of ruining the service for everyone else, he has to pay the administrator to do so. It's second aim is to force users to remain anonymous by default (meaning they all look the same), from the creation of their account. If they want to deanonymize themselves afterward, it will be their doing.
[What is MoneroSSO]
MoneroSSO is an automated sign-up system that is based on monero transactions. it is composed of a main monero address, where you need to send some monero to be able to signup there. Once the monero is sent, you will be able to use your transaction ID to access your account page, where your credentials are for the other services that are onboarded to MoneroSSO. If you want to top up your account, your account page will display another monero address, where you will be able to add more time to your account.
[How to use MoneroSSO]
First go to the MoneroSSO onion URL using the tor browser, at http://4o4sum57qjta773vn6h7dxgdyuwstcmgqpegewhfzr7m6bh2igsrceqd.onion/
Then as you can see, if you want to sign up, you need to send some monero to the sign-up XMR address.
Send at least 0.01XMR there if you want to sign up, then wait 20-40minutes for the transaction to be detected and your account to be created.
Then you take your transaction ID (which is 65 characters long, as it is displayed in your monero wallet, example: atui6diu4zae7aixies9oovahthiel4azeiyae5ootohr6ooJoaqu0rijah7phieb)
Then you can access your account credentials at the URL like so : (format is http://url.onion/txid/index.html)
In that page, you will see your default credentials (random username, and password), and another shorter password for invidious specifically. as it has different password requirements.
Warning: Be aware that the transaction ID must remain known only by you! If you give it to someone else, they potentially have access to all of your accounts! I recommend saving it inside of a keepass .kdbx file.