---
id: "hardman-conventions-for-opaque-identifier-aliases-coia"
type: "specification"
type_label: "Specifications and glossaries"
title: "COIA 2.0: Conventions for Opaque Identifier Aliases"
maintainer: "Daniel Hardman"
authors:
  - "Daniel Hardman"
date: "2025-08-28"
year: 2025
reading_level: "normative"
reading_level_label: "Normative"
reading_level_meaning: "the specifications and the documents they defer to"
evidence: "normative"
evidence_meaning: "a specification or a requirement in one"
status: "quiet"
status_meaning: "no change in six to eighteen months; still correct"
access: "public"
access_meaning: "anyone with the link"
topics:
  - "specifications"
roles:
  - "developer"
  - "security-architect"
  - "standards-policy"
source_url: "https://dhh1128.github.io/coia"
source_license: null
source_license_note: null
found_on: "hardman-papers"
kerisse_credit: false
abstract_license: "CC BY 4.0"
abstract_license_url: "https://creativecommons.org/licenses/by/4.0/"
abstract_attribution: "KSKB, the KERISuite Knowledge Base (https://kskb.dev/)"
last_checked: "2026-10-15"
kskb_url: "https://kskb.dev/cards/hardman-conventions-for-opaque-identifier-aliases-coia/"
kskb_app_url: "https://kskb.dev/#item/hardman-conventions-for-opaque-identifier-aliases-coia"
kskb_record_url: "https://kskb.dev/data/kskb/resources/hardman-conventions-for-opaque-identifier-aliases-coia"
kskb_markdown_url: "https://kskb.dev/export/cards/hardman-conventions-for-opaque-identifier-aliases-coia.md"
---

# COIA 2.0: Conventions for Opaque Identifier Aliases

A specification of a convention for human-readable labels (aliases) for opaque identifiers such as decentralized identifiers (DIDs), KERI autonomic identifiers (AIDs), keys and account numbers. It defines alias generation from three fields (who, role, scope), normalization, a flag registry for safety warnings, and matching. For developers of wallets, key managers and other tools that label identifiers.

Labels: reading level Normative; evidence normative (a specification or a requirement in one).
Source: https://dhh1128.github.io/coia (license not recorded).
The abstract is KSKB's own text under Creative Commons Attribution 4.0 (CC BY 4.0), https://creativecommons.org/licenses/by/4.0/; credit KSKB, the KERISuite Knowledge Base (https://kskb.dev/).