title: "Uport Specs" index: 3 category: "specs" type: "reference" source: "https://github.com/uport-project/specs/blob/develop/README.md"
uPort Specs
uPort is a platform for user centric identity and communication. The platform currently consists of our mobile app, Ethereum smart contracts and number of open protocols for signed messages and message flow.
Identities
An identity in uPort is really just someone or something that can sign data or transactions and also receive signed data about itself.
An identity has:
- An Identifier in the form of a Decentralized ID (DID)
- A signing key
- A public key stored on the uPort Registry
An identity can:
- Sign JWTs (JSON Web Tokens)
- Receive requests for disclosure about themselves
- Receive and store signed third party verifications about themselves
- Sign Ethereum transactions
Identities created using the uPort Mobile App
Currently most uPort users manage their identities through our mobile app. Identities created today consist of an instance of the Proxy smart contract deployed on a supported Ethereum-compatible blockchain.
Request Flows
A request will typically be signed by a client app and sent to mobile app using this generic request flow:
We currently support the following flows:
- Selective Disclosure Flow
- Send Verification Flow
- Ethereum Transaction Request Flow
- Private Chain Flow
More about request flows
Request and Response Transports
There are various ways that requests can be sent to the uPort app and how responses can be returned.
Request/Response Transports
Off-chain Messages
Most request and responses are performed privately off-chain between the different parties to a flow.
Most off-chain messages consist of signed JWTs (JSON Web Tokens) as defined in RFC 7519. Signatures are verified using our simple uPort PKI (see later in this document).
More about Off-chain Messages
On-chain Transactions
The user can sign Ethereum transactions using the mobile app.
More about Signing Ethereum transactions
uPort PKI
uPort implements a simple yet general purpose decentralized PKI system making it easy to create and verify off-chain JWT messages.