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)
  • Authenticate themselves to a third party
  • Disclose private information about themselves
• 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.

More about the uPort PKI