Additional Functional Details:
Everyone is very excited about NFTs right now. Using an NFT as an authentication certificate opens up a whole new world of possibilities. We will provide a NFT based access service that will create even more excitement, increase adoption, drive additional transactions on Cardano, and quite possibly increase the value of NFTs.
Want the ability to grant NFT-based access to the executive bathroom at work? NFTkey.me will get you there. (hopefully you laughed)
On a more serious note, access-control to private discord channels, newsletters, websites, mobile applications and more can governed by proven Cardano-based NFT ownership.
Maybe someone creates a really exciting new virtual game. Within the game, there's a special "Star Wars" themed bar that only people with a combination of NFTs can enter (let's say you need a S1 CardanoKidz and a SpaceBudz to get in). Nftkey.me will provide the service that game can use for access control.
These are just a couple ideas; we hope you get the picture. NFT based access-control will drive even greater demand for NFTs, increase adoption of Cardano, increase use of the network, and generally show off what's possible.
We've already documented the base use cases and functional requirements to make all of this happen.
Technical Details:
We will build a service for users to verify and manage what NFTs they own as well as track ownership over time. There are several possibilities of how this can be accomplished. The first implementation of the service will have a user provide an address they own and then provide them an ada amount to send to that address from the same wallet. This confirms ownership of the staking key and will allow us to query all NFTs they own. They will be able to do this for any number of wallets they own and we will be able to automatically detect new NFTs added to the wallet automatically. Future iterations may look into providing a mechanism to sign messages using the private keys that own the NFT. The main components of the NFT ownership service will involve account creation, wallet ownership flows, a service to monitor addresses using Blockfrost.io and a database to store all the data.
The service will then allow integrators to access users' information using standard OAuth 2 authorization code and user consent flows. An integrator will create an account, provide appropriate redirect urls and receive credentials. The integrators will then redirect users to our service, where the user will consent to give access to a list of their owned NFTs to a particular integration. The integrator will then be provided with an access key they could use to query our API for NFTs the user owns. Components of this integrator service will include an OAuth 2 server, integrator creation flows, an API for querying a user's owned NFTs which will also utilize Blockfrost.io, documentation on how to use the service, and an example implementation. This may also include a service to monitor NFTs moving between wallets and notifications to integrators.
The benefit to this architecture is that user's only have to verify wallets they own once, then can simply consent to access to their information for each integration. They don't need to prove ownership multiple times which can be inconvenient, especially when using hardware or offline wallets.
Challenge Question:
How does NFT Key create a positive developer experience that helps the developer focus on building successful apps?
Developers just want to build. They don't want to build tools to then build. NFT Key will become a powerful tool in developers' toolboxes that help them create applications, forums, websites, and more that utilize NFTs in fun and unique ways. What better experience for a developer to need a tool and find that it's already available to use?
Metrics:
How does NFT Key impact the challenge metrics around the question, "Did we manage to make it easier for developers to build on top of Cardano?"
We're in the early days of Cardano. NFTs are the big thing that have traction right now. Savvy developers are figuring out how to take advantage of this community interest.
A natural next step is utilizing NFTs for a functional purpose. But every developer shouldn't need to replicate the same functionality over and over again. NFTkey.me will provide the services necessary for developers to integrate NFT based OAuth 2 flows into their apps. This will:

• Attract developers who are looking for out of the box capabilities and services
• Enable developers to then focus on their area of expertise and specific business cases
• Drive integrated use cases and platforms built on Cardano
• Increase overall development activity which will drive greater sense of community and conversations

We believe that NFT Key will drive a whole new set of development activities on Cardano.
Personnel:
Chris and Dan have the necessary skills and experience to successfully execute this work within the proposed timeframe. We've successfully run stake pools on the ITN and Mainnet for over 12 months (this is verifiable). This includes the same front-end, back-end, blockchain and operations experience necessary to successfully execute this proposal.
Separately (admittedly less verifiable), we've previously co-founded a social-media related startup and have both worked professional in software related R&D, operations, and project management related fields for close to two decades each.
We have access to additional personnel with the necessary skill sets to crash/fast track (project management terms for bringing more people and doing things in parallel) the work if desired. However, these resources might not be the most cost-effective option.
Alternatively, we'd prefer to hire and collaborate with front-end and back-end developers already working in the Cardano ecosystem. This will be a great way for us to grow our network, assess abilities of other developers in within the ecosystem, and provide opportunities for other people too.
Budget:

• Front-end web development - $10,000
• Back-end web development - $15,000
• Marketing & Business Development - $10,000
• Ongoing Operations for 12 months - $10,000
• Hosting, Tools & Services - $2,500
• Contingencies (Reserves) - $2,500

Schedule:

• Prior to award - Given a positive initial response to our proposal, we'll begin prototyping the service "at-risk" prior to voting.
• 2 months ARA – We will launch a base service for user authentication and integrator account creation within 2 months after receipt of award (ARA). Assuming an award date of June 1st, our public launch date will be August 1st.
• 3 months ARA – We will launch our first open-sourced integration example within 3 months after receipt of award.
• 0-6 months ARA – Funding provides for marketing and business development for 6 months after receipt of award.
• 0-12 months ARA – The service will be supported for a minimum of 12 months at which time a business assessment will take place to assess the opportunity for ongoing operations.

Success Criteria:

• Success after 3 months looks like – An operational service with a working open-sourced integration example.
• Success after 6 months looks like – At least 3 integrators using our service – suggesting significant developer interest in using NFT Key.
• Success after 12 months looks like – At least 20 integrators using our service – meaning significant development activity driven by NFT Key.

Collaboration, Marketing & Business Development:
We are collaborating with numerous Cardano community members and teams including multiple other Project Catalyst proposals including:

• We plan to use Blockfrost, by Five Binaries, as an important part of our overall architecture. 5 Binaries has numerous active proposals in Project Catalyst. They've been great to work with already!
• NFT-DAO - We are exploring ways of working with NFT-DAO.org to work together to bring the value of both technologies to the #Cardano community! NFT-DAO was a Project Catalyst Fund 3 winner.
• We are collaborating with an unannounced consumer product project being built on Cardano by @BullishDumpling and @LeadTimeNull (the lead authors of the Project Catalyst proposals: The China Info Hub and The Great Filter, and SPOs of pools FIKA and NANI). [ More information will follow in a week from now ]

We've sought and received feedback from community members and NFT creators including Hashoshi (blockchain developer and YouTube commentator), Alessandro (creator of Space Budz) and Cardano Buzz to name a few.
We're actively engaged with a number of other organizations with interest in utilizing NFT Key including the exciting possibility of introducing a professional sports franchise into the Cardano ecosystem.
After the proposal is finalized, we will comment below with additional partnership and collaboration updates.