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The Identity Overlay Network (ION) is a DID Method implementation using the Sidetree protocol atop Bitcoin


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ION is a public, permissionless, Decentralized Identifier (DID) network that implements the blockchain-agnostic Sidetree protocol on top of Bitcoin (as a 'Layer 2' overlay) to support DIDs/DPKI (Decentralized Public Key Infrastructure) at scale.

IMPORTANT NOTE: The majority of ION's code is developed under the blockchain-agnostic Sidetree protocol's repo:, which this project uses internally with the code required to run the protocol on Bitcoin, like the ION network.

Key Points:

  • ION is public and permissionless - the system is decentralized, no company, organization, or group owns/controls the identifiers and DPKI entries in the system, and no one dictates who can participate.
  • ION doesn't introduce new tokens/coins - Bitcoin is the only unit of value relevant in the operation of the on-chain aspects of the ION network.
  • ION is not a sidechain or consensus system - the network nodes do not require any additional consensus mechanism.
  • See design document for specific design details and decisions.

Operating Model

See the operating model document on processes and activities performed to maintain ION.

How does ION work?

By leveraging the blockchain-agnostic Sidetree protocol, ION makes it possible to anchor tens of thousands of DID/DPKI operations on a target chain (in ION's case, Bitcoin) using a single on-chain transaction. The transactions are encoded with a hash that ION nodes use to fetch, store, and replicate the hash-associated DID operation batches via IPFS. The nodes process these batches of operations in accordance with a specific set of deterministic rules that enables them to independently arrive at the correct DPKI state for IDs in the system, without requiring a separate consensus mechanism, blockchain, or sidechain. Nodes can fetch, process, and assemble DID states in parallel, allowing the aggregate capacity of nodes to run at tens of thousands of operations per second.

Frequently Asked Questions

See Q&A.

Building the project:

Please use the following guide to setup the various services that comprise an ION node: ION Installation Guide

Partner Organizations:

ION (an instantiation of Sidetree on Bitcoin) has been developed as a part of the Decentralized Identity Foundation