SSI & KERI

KERI is part of the SSI ecosystem, but it isn’t owned by SSI.**
It’s a foundational identity and trust layer that SSI systems can use to manage identifiers, keys, and credentials without relying on a blockchain.

What is SSI?

SSI systems generally require:

1. Identifiers
   Secure, persistent identifiers for people, orgs, and devices.

2. Verifiable Data
   A way to issue and verify claims/credentials.

3. Trust Infrastructure
   A mechanism for validating key history, rotation, and integrity without a central provider.

Traditional SSI relies on:

• DIDs
• Verifiable Credentials
• Blockchains or registries
• PKI-based trust
• Agents and wallets

Where KERI Fits

KERI (Key Event Receipt Infrastructure) provides a decentralized, portable trust layer for identifier and key management.
It supplies features that classical DID methods don’t:

• Self-certifying identifiers (derived directly from keys)
• Verifiable key rotations
• Immutable, hash-linked event history (DAG)
• Witnessing and receipts instead of global ledgers
• Fully portable identifiers and credentials
• Ledger-optional architecture

In SSI terms:

• KERI is a DID method (e.g., did:keri:...)
• KERI provides the trust substrate for credentials
• KERI is paired with ACDC as its native credential format

Interoperability With SSI Standards

KERI works alongside or instead of other SSI components:

• W3C DIDs
• W3C Verifiable Credentials
• DIDComm
• VC-JWT and LD-Signatures
• Blockchain-anchored DID methods
• Traditional ledgers and revocation registries

You can use KERI as:

• a DID method
• a portable trust anchor
• a key management and rotation engine
• an identity substrate for organizations, devices, or humans

Mental Model

• Blockchain SSI: Trust is anchored in the ledger.
• KERI SSI: Trust is anchored in the verifiable key event log.
• ACDC: The verifiable data container layer on top of KERI.

Both are SSI — they just implement the trust layer differently.

Summary

Is KERI part of SSI?
Yes.
It’s a modern and efficient approach that gives SSI:

• portable decentralized identifiers
• verifiable rotations
• self-certifying trust
• ledger independence
• a powerful credential layer (ACDC)

KERI = SSI without requiring a blockchain.

Overview Diagram

                  +-----------------------------+
                  |        SSI Ecosystem        |
                  +-----------------------------+
                            /        \
                           /          \
                          /            \
                         v              v

            +------------------+    +-------------------+
            |   Identifiers    |    | Verifiable Data   |
            |   (DIDs, AIDs)   |    | (VCs, ACDCs)      |
            +------------------+    +-------------------+
                      |                      |
                      |                      |
                      v                      v

      +---------------------------------------------------+
      |        KERI: Key Event Receipt Infrastructure     |
      |---------------------------------------------------|
      | - Self-certifying identifiers (AIDs)              |
      | - Key events (inception, rotation, delegation)    |
      | - Witnessing & receipts                           |
      | - Immutable event DAG (KEL)                       |
      | - No blockchain required                          |
      +---------------------------------------------------+
                      |
                      |
                      v

            +---------------------------+
            |       ACDC Layer          |
            |  (Authentic Chained Data) |
            | - Credentials             |
            | - Attestations            |
            | - Portable proofs         |
            +---------------------------+
                      |
                      |
                      v

              +-----------------------+
              |   Agents & Wallets    |
              | (Holders, Issuers,    |
              |  Verifiers)           |
              +-----------------------+
                      |
                      |
                      v

              +-----------------------+
              |  Applications & Use   |
              |       Cases           |
              +-----------------------+

• SSI, KERI & AI
• SSI, KERI & UTXO - Conceptual Relationship