Appendices: Tools, Terms, and Technical Reference

This appendix is your one-stop reference for the technical terms, DID methods, and foundational materials that support decentralized identity development on the XRP Ledger.

Use it to refresh your memory, explain key concepts to colleagues, or explore deeper implementations of DIDs and verifiable credentials.

A. Glossary of DID / VC Terminology

🧩 DID (Decentralized Identifier): A globally unique, cryptographically verifiable identifier that proves control of a public/private key pair.

🛠️ VC (Verifiable Credential): A tamper-proof, digitally signed claim (e.g., “KYC Verified”) issued by a trusted party and presented by a DID holder.

🔐 Credential (XRPL Object): A native on-ledger data object (per XLS-70) that represents a signed, verifiable claim linked to a DID.

🧱 DID Object (XRPL Token): An on-ledger representation of a decentralized identifier on XRPL, registered using XLS-40. This links a DID to an XRPL account.

📜 XLS-40 – Native XRPL DID Method: Defines the did:xrpl: method, enabling DID creation, resolution, and linkage to ledger accounts.
https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0040-decentralized-identity 

📜 XLS-70 – Credential Object: Supports creation of on-ledger, verifiable credentials–anchoring trust to the XRP Ledger.
https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0070-credentials 

📜 XLS-80 – Permissioned Domains: Lets domain owners restrict or allow access based on DID-linked credentials for identity-aware interactions.
https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0080-permissioned-domains 

📜 XLS-81 – Permissioned DEX: Adds access controls to XRPL’s decentralized exchange (DEX), enabling KYC/AML compliance via credentials.
https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0081-permissioned-dex 

🔺 Issuer / Holder / Verifier: The three roles in a VC system: the entity issuing a credential, the person holding it, and the party verifying it.

🔓 Selective Disclosure: A privacy technique allowing users to reveal only the data necessary from a credential (e.g., “Over 18” without showing a birthdate).

B. Common DID Methods: Quick Comparison

🔷 did:xrpl

Network: XRP Ledger
Storage: DID object + optional off-chain data
Cost: Very low (no gas fees)
Use Cases: Finance, compliance, institutional identity
Strengths: Speed, cost-efficiency, KYC/AML compliance, XRP DEX integration
Support: Proposed via XLS-40, built for W3C compatibility

🟢 did:ion

Network: Bitcoin (via Sidetree)
Storage: IPFS + anchored in Bitcoin
Cost: Low
Use Cases: General identity, academic credentials
Strengths: Fully decentralized, no third-party dependencies
Limitations: Slower update cycles due to Bitcoin anchoring

🟡 did:ethr

Network: Ethereum
Storage: On-chain (smart contract-based)
Cost: High (subject to Ethereum gas fees)
Use Cases: dApps, web3 logins
Strengths: Smart contract flexibility
Limitations: Not ideal for financial/compliance due to cost and scalability

🟣 did:key

Network: None (self-contained)
Storage: Entirely off-chain
Cost: Free
Use Cases: Ephemeral or local identity
Strengths: Simplicity
Limitations: Not resolvable or shareable at scale

📌 Summary:

While multiple DID methods exist, did:xrpl stands out for financial-grade applications, due to:

• Fast settlement
• Low transaction costs
• Built-in compliance support via XLS-80/81

C. Reference Materials and Developer Links

Here are the most important links for deeper exploration and development:

🌐 XRPL + Identity Development

📘 XRPL Identity Docs:
https://xrpl.org/docs/concepts/decentralized-storage/decentralized-identifiers 

🧰 XRP Ledger Developer Resources:
https://xrpl.org/docs 

📚 W3C Core Specifications

📄 W3C DID Core Specification:
https://www.w3.org/TR/did-core/ 

📄 W3C Verifiable Credentials Data Model:
https://www.w3.org/TR/vc-data-model/#ecosystem-overview 

🛠️ Open-Source Identity Toolkits

🔗 DIDKit (for multi-method support):
https://github.com/spruceid/didkit 

🔗 Veramo (VC toolkit):
https://veramo.io 

🔗 Hyperledger Aries Framework:
https://aries.hyperledger.org/ 

These references form the technical foundation of this course – and your next steps as a DID developer or identity designer.