feat: add EVES-007 ENVITED-X Blockchain Identifier URN Schema

EVES/EVES-007/eves-007.md

@@ -0,0 +1,172 @@
+---
+eves-identifier: 007
+title: ENVITED-X Blockchain Identifier URN Schema
+author: Carlo van Driesten (@jdsika)
+discussions-to:
+status: Draft
+type: Standards
+created: 2025-03-04
+requires: ["EVES-001", "EVES-002", "EVES-006"]
+replaces: None
+---
+
+## Abstract
+
+This specification defines a **uniform resource name (URN) schema** for uniquely identifying smart contracts and transaction hashes across multiple blockchains, including **Tezos, Ethereum, and Etherlink**.  
+It ensures **compatibility with CAIP-10**, **DID:PKH**, and other **chain-agnostic specifications** by referencing standard chain namespaces and `chain_id` definitions.  
+The URN schema provides a structured approach for **interoperable cross-chain asset management** and **transaction referencing**, aligning with the ENVITED-X Data Space architecture.
+
+## Motivation
+
+In blockchain-based ecosystems such as ENVITED-X, referencing **smart contracts** and **operations** requires a **standardized, human-readable, and resolvable format**.  
+Existing solutions such as **CAIP-10 (Chain Agnostic Improvement Proposal 10)** define **account identifiers**, but they do not extend to **contract addresses and transaction hashes**.  
+The lack of a unified schema creates **interoperability challenges** when integrating **Tezos (FA2.1, TZIP-21 metadata)**, **Ethereum (ERC-721, ERC-1155 NFTs)**, and **Etherlink (Optimistic Rollup Layer 2)** into the ENVITED-X Data Space.
+
+This EVES addresses the gap by defining a **URN schema** that:
+
+- Provides a **consistent, chain-agnostic way** to reference **smart contracts and transactions**.
+- Aligns with **CAIP-10 conventions**, ensuring **namespace compatibility**.
+- Supports **Tezos implicit (tz1, tz2, tz3) and originated (KT1) accounts**.
+- Differentiates between **Layer 1 (Tezos, Ethereum) and Layer 2 (Etherlink)** transactions.
+
+## Specification
+
+### 1. URN Schema Definition
+
+The URN schema follows a **structured format** using **blockchain namespaces**, ensuring **consistency and interoperability**.
+
+#### 1.1 Smart Contract Identifiers
+
+A **smart contract** is uniquely referenced using the following format:
+
+```json
+urn:blockchain:{chain_namespace}:{chain_id}:contract:{contract_address}
+```
+
+##### Smart Contract Example Mappings
+
+| Blockchain              | Namespace | Chain ID          | Example URN |
+|-------------------------|-----------|-------------------|--------------------------------------------------------------------------------------|
+| **Tezos (Ghostnet)**    | `tezos`   | `NetXnHfVqm9iesp` | `urn:blockchain:tezos:NetXnHfVqm9iesp:contract:KT1PCaD2kmgCHy15wQ1gpqZUy9RLxyBVJdTF` |
+| **Ethereum (Mainnet)**  | `eip155`  | `1`               | `urn:blockchain:eip155:1:contract:0xABC123456789...`                                 |
+| **Etherlink (Layer 2)** | `eip155`  | `42793`           | `urn:blockchain:eip155:42793:contract:0x646B92C8f21e55DF67E766047E4bD7bEdF8DfA14`    |
+
+> **_NOTE:_**
+>
+> - The **namespace** follows **CAIP-2** (e.g., `tezos`, `eip155` for Ethereum).
+> - The **chain_id** follows **CAIP-10**, ensuring unique chain differentiation.
+> - **Smart contracts (KT1, 0x) are explicitly named** under the `contract` identifier.
+
+#### 1.2 Transaction Hash Identifiers
+
+A **transaction (operation) hash** is referenced using:
+
+```json
+urn:blockchain:{chain_namespace}:{chain_id}:tx:{transaction_hash}
+```
+
+##### Transaction Example Mappings
+
+| Blockchain              | Namespace  | Chain ID          | Example URN                                                                                         |
+|-------------------------|------------|-------------------|-----------------------------------------------------------------------------------------------------|
+| **Tezos (Ghostnet)**    | `tezos`    | `NetXnHfVqm9iesp` | `urn:blockchain:tezos:NetXnHfVqm9iesp:tx:oojtGLnHuS8og5WGf8jF8EoxTbegfrXvpxzvyPiW2GYZFGbFLaJ`       |
+| **Ethereum (Mainnet)**  | `eip155`   | `1`               | `urn:blockchain:eip155:1:tx:0xad0fa6b98b66bc19ab4936d1181697ac7f1e19755e1501e4e250434200a32cba`     |
+| **Etherlink (Layer 2)** | `eip155`   | `42793`           | `urn:blockchain:eip155:42793:tx:0xad0fa6b98b66bc19ab4936d1181697ac7f1e19755e1501e4e250434200a32cba` |
+
+> **_NOTE:_**
+>
+> - **Operation hashes on Tezos are prefixed with `tx:`**.
+> - **Ethereum and Etherlink transactions follow the Keccak-256 hash format**.
+
+### 2. Standardization Considerations
+
+- **CAIP-2 & CAIP-10 Alignment**:  
+  - The `chain_namespace` and `chain_id` **strictly follow** CAIP-2 & CAIP-10 conventions.
+  - `eip155`, `tezos` **retain compatibility with existing tooling**.
+
+- **Layer 2 Distinction**:  
+  - **Etherlink URNs explicitly specify their Layer 2 chain ID** (`ghostnet: 128123`, `mainnet: 42793`).
+  - This prevents **collision between Layer 1 and Layer 2 assets**.
+
+- **Human-Readable & Resolvable**:  
+  - This URN structure can be used in **metadata files (TZIP-21, ERC-721)**.
+  - Enables **cross-chain verification of contracts and operations**.
+
+### 3. Use Cases
+
+- **NFT Metadata (TZIP-21, ERC-721, ERC-1155)**
+  - Store **contract & transaction references** in **token metadata** crosschain.
+
+- **Cross-Chain Credential Verification (EVES-005, EVES-006)**
+  - Supports contract-based **Verifiable Credentials (SD-JWT VC)**.
+
+- **ENVITED-X Asset Tracking**
+  - Standardized **contract and transaction tracking** across chains.
+
+### **4. MIME Type for Blockchain URNs**
+
+To ensure structured and standardized handling of **URN-based blockchain references**, this specification defines a MIME type for representing **contract and transaction identifiers** in a machine-readable format.  
+
+#### **4.1 MIME Type Definition**
+
+The following MIME type is introduced to denote **blockchain URNs** in JSON-based metadata and API responses:
+
+```json
+application/vnd.eves.blockchain-urn+json
+```
+
+#### **4.2 Rationale**
+
+- **`application/`** → Indicates structured data.  
+- **`vnd.eves.`** → Specifies the ENVITED-X standardization scope.  
+- **`blockchain-urn`** → Clearly identifies the content as a **URN-based blockchain reference**.  
+- **`+json`** → Specifies that the format is **compatible with JSON-based data structures**.
+
+#### **4.3 Example Usage**
+
+The MIME type is used in metadata files, API payloads, and verifiable credential documents where blockchain URN references are required.  
+
+##### **Example: NFT Metadata (TZIP-21, ERC-721)**
+
+```json
+{
+  "name": "Digital Twin Smart Contract",
+  "artifactUri": "ipfs://bafybeidhmknqn4co...",
+  "mimeType": "application/vnd.eves.blockchain-urn+json",
+  "contractURN": "urn:blockchain:tezos:NetXnHfVqm9iesp:contract:KT1PCaD2kmgCHy15wQ1gpqZUy9RLxyBVJdTF",
+  "mintingTx": "urn:blockchain:eip155:1:tx:0xad0fa6b98b66bc19ab4936d1181697ac7f1e19755e1501e4e250434200a32cba"
+}
+```
+
+Example: API Response
+
+```json
+{
+  "status": "success",
+  "data": {
+    "urn": "urn:blockchain:etherlink:ghostnet:contract:0xDEF987654321...",
+    "mimeType": "application/vnd.eves.blockchain-urn+json"
+  }
+}
+```
+
+This MIME type ensures interoperability across blockchain networks, metadata specifications (TZIP-21, ERC-721), and decentralized identity frameworks (DID:PKH, SD-JWT).
+
+## Backwards Compatibility
+
+This EVES introduces a **new URN schema** but does not conflict with **existing CAIP-10, TZIP-21, or ERC-721 standards**.  
+It is fully backward-compatible with Tezos, Ethereum, and Etherlink **without requiring changes to current implementations**.
+
+## References
+
+1. [CAIP-2: Blockchain Namespace Specification](https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-2.md)
+2. [CAIP-10: Blockchain Account Specification](https://github.com/ChainAgnostic/CAIPs/blob/main/CAIPs/caip-10.md)
+3. [Tezos TZIP-21](https://gitlab.com/tzip/tzip/-/blob/master/proposals/tzip-21/tzip-21.md)
+4. [Ethereum ERC-721 Standard](https://eips.ethereum.org/EIPS/eip-721)
+5. [Etherlink Documentation](https://docs.etherlink.com/)
+6. [Etherlink Network Information](https://docs.etherlink.com/get-started/network-information/)
+
+## Implementation
+
+- The ENVITED-X Data Space will **adopt this URN schema** in **metadata specifications** (see EVES-003, EVES-006).
+- Future EVES will explore **URN resolvers** for cross-chain asset lookup.

EVES/SUMMARY.md

@@ -12,3 +12,4 @@
 * [EVES-004: ENVITED-X Roles and Responsibilities of EVES Editors](./EVES-004/eves-004.md)
 * [EVES-005: ENVITED-X Contract Negotiation Process](./EVES-005/eves-005.md)
 * [EVES-006: ENVITED-X Scaling Architecture](./EVES-006/eves-006.md)
+* [EVES-007: ENVITED-X Blockchain Identifier URN Schema](./EVES-007/eves-007.md)

README.md

@@ -18,3 +18,4 @@
 | [004](./EVES/EVES-004/eves-004.md) | ENVITED-X Roles and Responsibilities of EVES Editors | Process   | Review |
 | [005](./EVES/EVES-005/eves-005.md) | ENVITED-X Contract Negotiation Process               | Process   | Review |
 | [006](./EVES/EVES-006/eves-006.md) | ENVITED-X Scaling Architecture                       | Process   | Draft  |
+| [007](./EVES/EVES-007/eves-007.md) | ENVITED-X Blockchain Identifier URN Schema           | Standards | Draft  |