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HCS Standards

Discover the comprehensive collection of Hashgraph Consensus Standards (HCS) authored by Hashgraph Online — enabling interoperable agent communication, registries, content inscription, and application composition.

Showing 15 of 15 items

HCS-1

Published

HCS-1: File Data Management

Core Data Management

Systematic approach to encode, chunk, upload, retrieve, and reassemble file data using Hedera Consensus Service. The foundation for data management on HCS.

Key Features: Data chunking, File reconstruction, Consensus-based storage

HCS-2

Published

HCS-2: Advanced Topic Registries

Core Data Management

Advanced methodologies for managing and interacting with Topic Registries within the HCS framework, enabling organized data discovery.

Key Features: Topic organization, Registry management, Data indexing

HCS-3

Published

HCS-3: Recursion within HCS

Core Data Management

Enables recursive referencing of inscriptions within Hedera Hashgraph, standardizing how resources reference and load other resources.

Key Features: Recursive references, Resource loading, Standardized linking

HCS-5

Published

HCS-5: Tokenized HCS-1 Files (Hashinals)

Digital Assets & NFTs

Standard for "inscribing" Hashinals utilizing both Hedera Consensus Service and Hedera Token Service for tokenized file assets.

Key Features: NFT creation, File tokenization, HTS integration

HCS-6

Published

HCS-6: Dynamic Hashinals

Digital Assets & NFTs

Inscribe and tokenize Hashinals with updatable metadata using non-indexed Topic IDs, enabling evolving digital assets.

Key Features: Mutable metadata, Dynamic updates, Flexible NFTs

HCS-7

Draft

HCS-7: Smart Hashinals

Digital Assets & NFTs

A Micro-DSL for Deterministic Topic Selection enabling dynamic NFTs whose metadata automatically updates based on smart contract state.

Key Features: Smart contracts, WASM processing, State-reactive NFTs

HCS-8

Published

HCS-8: Poll Topic Standard

Governance & Polling

Framework for using HCS topics to manage decentralized polls and voting mechanisms with transparent, auditable results.

Key Features: Decentralized voting, Poll management, Result aggregation

HCS-9

Published

HCS-9: Poll Metadata Schema

Governance & Polling

Defines the schema to describe and execute polls in conjunction with HCS-8, ensuring standardized poll structure and execution.

Key Features: Poll schemas, Metadata standards, Execution framework

HCS-10

Draft

HCS-10: OpenConvAI Standard

AI & Communication

Enables AI agents to autonomously discover and communicate through Hedera's Consensus Service with secure, verifiable interactions.

Key Features: AI communication, Agent discovery, Decentralized registry

HCS-11

Published

HCS-11: Profile Metadata Standard

Identity & Profiles

Standardizes profile metadata for entities on Hedera, enabling consistent identity representation across applications.

Key Features: Profile metadata, Identity standards, Cross-app compatibility

HCS-12

Draft

HCS-12: HashLinks

Application Composition

Composes WASM actions, Gutenberg UI blocks, and assemblies into interactive on-chain experiences registered via HCS topics.

Key Features: WASM actions, Gutenberg blocks, Assembly composition

HCS-13

Draft

HCS-13: Schema Registry

Infrastructure

Provides a standard way to define, register, and reference schemas for data validation and structure in the Hedera ecosystem.

Key Features: Schema validation, Type-safe data, JSON Schema support

HCS-14

Draft

HCS-14: Universal Agent ID Standard

AI & Communication

W3C DID-based standard for deterministic, globally unique AI agent identifiers. Enables cross-protocol agent discovery and communication.

Key Features: Agent identification, Cross-protocol routing, DID compatibility

HCS-19

Draft

HCS-19: AI Agent Privacy Compliance

AI & Communication

The HCS-19 standard defines a comprehensive, ISO/IEC TS 27560-aligned framework for AI agents to document and manage privacy compliance on Hedera through HCS topics.

Key Features: Privacy compliance, Consent management, Data processing records, GDPR/CCPA support

HCS-20

Published

HCS-20: Auditable Points Standard

Points & Rewards

Manages and audits points on Hedera Hashgraph, inspired by BRC-20. Enables transparent reward systems and loyalty programs.

Key Features: Point management, Audit trails, Reward systems