🔗 HEDERA BLOCKCHAIN INTEGRATION - LAFAEKSTREET

📋 OVERVIEW

LafaekStreet uses Hedera Consensus Service (HCS) to create an immutable, transparent record of all road infrastructure reports submitted by citizens in Timor-Leste. This ensures that reports cannot be deleted or tampered with, providing accountability and trust in the civic engagement process.

📁 Files in This Folder

File	Description
`hedera-playground.js`	Topic creation script used in Hedera Portal Playground
`portal_gedera_playground.png`	Screenshot of Hedera Portal Playground running the script
`Topic_0.0.7855971.png`	Hashscan screenshot showing Reports Topic messages with real citizen reports
`Topic_0.0.7855972.png`	Hashscan screenshot showing Status Updates Topic messages with AI validation results
`Example_Transaction.png`	Hashscan screenshot showing a single transaction detail with actual costs

🎯 WHY HEDERA BLOCKCHAIN?

Transparency

Every report is permanently recorded on the blockchain, creating a public audit trail that citizens, government agencies, and oversight organizations can verify independently.

Immutability

Once a report is submitted to Hedera, it cannot be altered or deleted, preventing corruption or manipulation of civic data.

Cost-Effective

Hedera transactions cost approximately $0.0001 USD per report, making it affordable for large-scale civic applications. Our real transaction data confirms this — a SUBMIT MESSAGE transaction costs only $0.00086 (see Example_Transaction.png).

Fast & Reliable

Hedera provides finality in 3-5 seconds with high throughput, ensuring real-time blockchain verification.

🏗️ HEDERA TOPICS ARCHITECTURE

LafaekStreet uses 2 HCS Topics on Hedera Testnet:

Topic 1: Reports Topic

Purpose: Stores initial report submissions
Data Stored: Report metadata, GPS location, issue type, severity, AI analysis results, images references
Topic ID: 0.0.7855971
View on Hashscan: 🔗 View Topic

Topic 2: Status Updates Topic

Purpose: Records all status changes (pending → in progress → fixed)
Data Stored: Status transitions, timestamps, agency actions, resolution details
Topic ID: 0.0.7855972
View on Hashscan: 🔗 View Topic

📊 TOPIC CONFIGURATION

Both topics are configured for maximum transparency:

javascript

{
  submit_key: null,        // Anyone can submit messages (public)
  admin_key: null,         // Immutable (cannot be deleted)
  auto_renew_period: 90 days,
  memo: "LafaekStreet - [Topic Purpose]"
}

Key Features:

✅ Public Submission - No private keys required to read messages
✅ Immutable - Topics cannot be deleted or modified
✅ Auto-Renewal - Automatically maintained on the network
✅ Transparent - All messages are publicly queryable

🔍 HOW IT WORKS

1. Citizen Submits Report

Mobile App → FastAPI Backend → Validation
     ↓
AWS S3 (Images) + PostgreSQL (Metadata)
     ↓
Prepare Blockchain Payload

2. Blockchain Recording

Report Data → AWS KMS (Sign) → Hedera HCS Topic
     ↓
Consensus Reached (3-5 seconds)
     ↓
Transaction Receipt with Sequence Number & Timestamp

3. Verification

Anyone Can Query:
- Hedera Mirror Node API
- Hashscan Explorer
- Direct Topic Message Query

Compare with PostgreSQL data
     ↓
Verify Integrity ✓

🛠️ TOPIC CREATION SCRIPT

File: `hedera-playground.js`

This script was executed in the Hedera Portal Playground (portal.hedera.com/playground) to create both HCS topics on Hedera Testnet.

Screenshot: Hedera Portal Playground

The screenshot shows the Hedera Portal Playground interface with:
Left sidebar: HCS tab selected with topic operations (Create, Update, Submit Message, Delete, Get by ID, etc.)
Code editor: Running hedera-playground.js with @hiero-ledger/sdk v2.75.0
Output panel: Showing successful creation of both topics with Topic IDs and Hashscan URLs
Chat Assistant: Built-in AI assistant helping with topic creation commands

What the Script Does:

Connects to Hedera Testnet using operator account 0.0.6255873
Creates Topic 1 (0.0.7855971): LafaekStreet Reports Topic — stores report submissions
Creates Topic 2 (0.0.7855972): LafaekStreet Status Updates Topic — stores status changes
Verifies both topics via Hedera Mirror Node API (testnet.mirrornode.hedera.com)
Outputs environment variables ready to copy into backend .env file

Full Script:

javascript

const {
  AccountId,
  PrivateKey,
  Client,
  TopicCreateTransaction,
} = require("@hiero-ledger/sdk"); // v2.75.0

async function main() {
  let client;
  try {
    const MY_ACCOUNT_ID = AccountId.fromString("0.0.6255873");
    const MY_PRIVATE_KEY = PrivateKey.fromStringECDSA("...");

    client = Client.forTestnet();
    client.setOperator(MY_ACCOUNT_ID, MY_PRIVATE_KEY);

    // CREATE TOPIC 1: REPORTS
    const txCreateTopic1 = new TopicCreateTransaction().setTopicMemo(
      "LafaekStreet - Reports Topic",
    );
    const txResponse1 = await txCreateTopic1.execute(client);
    const receipt1 = await txResponse1.getReceipt(client);
    const topicId1 = receipt1.topicId.toString();

    // CREATE TOPIC 2: STATUS UPDATES
    const txCreateTopic2 = new TopicCreateTransaction().setTopicMemo(
      "LafaekStreet - Status Updates Topic",
    );
    const txResponse2 = await txCreateTopic2.execute(client);
    const receipt2 = await txResponse2.getReceipt(client);
    const topicId2 = receipt2.topicId.toString();

    // VERIFY VIA MIRROR NODE
    const response1 = await fetch(
      `https://testnet.mirrornode.hedera.com/api/v1/topics/${topicId1}`,
    );
    const response2 = await fetch(
      `https://testnet.mirrornode.hedera.com/api/v1/topics/${topicId2}`,
    );

    // OUTPUT FOR .ENV FILE
    console.log(`HEDERA_TOPIC_ID_REPORTS="${topicId1}"`);
    console.log(`HEDERA_TOPIC_ID_STATUS_UPDATES="${topicId2}"`);
  } catch (error) {
    console.error("Error:", error);
  } finally {
    if (client) client.close();
  }
}
main();

Output:

✅ Topic 1 Created: 0.0.7855971
✅ Topic 2 Created: 0.0.7855972

HEDERA_TOPIC_ID_REPORTS="0.0.7855971"
HEDERA_TOPIC_ID_STATUS_UPDATES="0.0.7855972"

📸 LIVE EVIDENCE — REAL REPORTS ON BLOCKCHAIN

The following screenshots show actual citizen reports from LafaekStreet recorded immutably on the Hedera Testnet blockchain. These are real submissions made through the mobile app, processed by our AI pipeline, and permanently stored on-chain.

Reports Topic (0.0.7855971) — Citizen Report Data

Hashscan URL: https://hashscan.io/testnet/topic/0.0.7855971

This screenshot shows messages #74–#78 on the Reports Topic. Each message contains a full report payload submitted by citizens, including:

report_id: Unique report identifier (e.g., LS-260220-0002, LS-260220-0007)
issue_type: AI-classified damage type (pothole, drainage, road_cracks)
severity: AI-determined severity level (medium, high, low)
location: GPS coordinates with latitude/longitude (e.g., -8.553..., 125.540...)
blockchain_metadata: Network (hedera-testnet) and version (1.0)
Timestamps: Precise consensus timestamps for each submission

Example message from the screenshot (Message #78):

json

{
  "report_id": "LS-260220-0002",
  "user_id_hash": "f984e7d63559099...",
  "issue_type": "pothole",
  "severity": "medium",
  "location": { "latitude": -8.553..., "longitude": 125.540... },
  "blockchain_metadata": { "network": "hedera-testnet", "version": "1.0" }
}

Status Updates Topic (0.0.7855972) — AI Validation & Status Changes

Hashscan URL: https://hashscan.io/testnet/topic/0.0.7855972

This screenshot shows messages S49–S53 on the Status Updates Topic. Each message records a status transition with AI validation comments, including:

old_status → new_status: Status transition tracking (pending → pending for initial AI validation)
comment: AI validation result with confidence score
changed_by: Hash of the user/system that triggered the change

Real AI validation results visible in the messages:

Message	Report ID	AI Comment	Date
S53	LS-260220-0002	`AI Validation: pothole detected with 85.0% confidence`	Feb 20, 2026
S52	LS-260220-0001	`AI Validation: pothole detected with 85.0% confidence`	Feb 20, 2026
S51	LS-260219-0001	`AI Validation: debris detected with 95.0% confidence`	Feb 19, 2026
S50	LS-260218-0001	`AI Validation: pothole detected with 85.0% confidence`	Feb 18, 2026
S49	LS-260217-0001	`AI Validation: road_cracks detected with 85.0% confidence`	Feb 17, 2026

This proves that every report goes through AI-powered damage analysis (Amazon Bedrock Nova 2 Lite) and the validation result is permanently recorded on the blockchain alongside the report data.

Example Transaction Detail — Real Cost Breakdown

Hashscan URL: https://hashscan.io/testnet/transaction/0.0.6255873@1771493372.580909013

This screenshot shows the actual cost of submitting a single report to the Hedera blockchain:

Field	Value
Transaction ID	`0.0.6255873@1771493372.580909013`
Type	SUBMIT MESSAGE
Topic ID	`0.0.7855971` (Reports Topic)
Payer Account	`0.0.6255873`
Consensus At	6:29 PM, Feb 19, 2026 (GMT+9)
Charged Fee	0.00871297 ℏ ($0.00086)
Max Fee	0.02000000 ℏ ($0.00198)
HBAR Price	$0.0989
Block	31723042
Node	0.0.4 Node 1 (Hedera)
Status	SUCCESS
Valid Duration	2 min

Key takeaway: A single blockchain report submission costs only $0.00086 USD (less than one-tenth of a cent). At this rate:

1,000 reports = $0.86
10,000 reports = $8.60
100,000 reports = $86.00

This makes blockchain transparency practically free for civic applications.

📈 BLOCKCHAIN DATA FLOW

💡 DATA STORED ON BLOCKCHAIN

Report Submission Payload:

json

{
  "report_id": "RPT-2026-001234",
  "user_id_hash": "sha256_hash",
  "issue_type": "pothole",
  "severity": "high",
  "location": {
    "latitude": -8.5569,
    "longitude": 125.5603,
    "municipality": "Dili"
  },
  "ai_analysis": {
    "confidence": 94.5,
    "damage_detected": true,
    "estimated_size": "0.8m diameter"
  },
  "images_hash": "sha256_of_s3_keys",
  "timestamp": "2026-01-15T10:30:45Z",
  "blockchain_metadata": {
    "network": "hedera-testnet",
    "signature": "kms_signature"
  }
}

Status Update Payload:

json

{
  "report_id": "RPT-2026-001234",
  "old_status": "pending",
  "new_status": "in_progress",
  "changed_by": "agency_id_hash",
  "comment": "Work scheduled for next week",
  "timestamp": "2026-01-16T14:22:10Z"
}

🔐 SECURITY & PRIVACY

Data Privacy:

Personal information (names, emails, phone numbers) is NOT stored on blockchain
Only hashed user IDs and report metadata are recorded
Images are stored on AWS S3, only S3 key hashes go to blockchain

Authentication:

All blockchain submissions are signed using AWS KMS with SECP256K1 keys
Private keys never leave AWS infrastructure
Signatures verify data integrity and origin

Transparency vs Privacy Balance:

ON BLOCKCHAIN ✓              NOT ON BLOCKCHAIN ✗
- Report ID                  - User name
- Issue type                 - Email address
- Location (GPS)             - Phone number
- Severity                   - Password
- Timestamp                  - Actual images
- Status changes             - Personal comments
- AI analysis results        - Private agency notes

🌐 PUBLIC VERIFICATION

Anyone can verify LafaekStreet reports:

Method 1: Hashscan Explorer

Visit: https://hashscan.io/testnet/topic/0.0.7855971

Method 2: Hedera Mirror Node API

bash

# Get all messages from Reports Topic
curl https://testnet.mirrornode.hedera.com/api/v1/topics/0.0.7855971/messages

# Get specific message by sequence number
curl https://testnet.mirrornode.hedera.com/api/v1/topics/0.0.7855971/messages/1

Method 3: In-App Verification

The mobile app includes a "Verify on Blockchain" button that:

Retrieves the report from PostgreSQL
Queries the corresponding Hedera transaction
Compares data hashes
Shows ✓ or ✗ verification status

💰 COST ANALYSIS

Actual Transaction Costs (from real data):

Based on our live transaction evidence (Example_Transaction.png):

Report Submission (SUBMIT MESSAGE):  $0.00086 USD  (0.00871297 ℏ)
Status Update (SUBMIT MESSAGE):     $0.00086 USD  (0.00871297 ℏ)
Topic Query (Read via Mirror Node):  FREE
HBAR Price at time of transaction:   $0.0989

Annual Cost Estimates (using real data):

Small Municipality (500 reports/month):

Reports:         500 × $0.00086 × 12 = $5.16/year
Status Updates:  500 × $0.00086 × 12 = $5.16/year
Total:                                 $10.32/year

National Scale (2,000 reports/month):

Reports:         2,000 × $0.00086 × 12 = $20.64/year
Status Updates:  2,000 × $0.00086 × 12 = $20.64/year
Total:                                   $41.28/year

Conclusion: Full blockchain transparency for an entire nation costs less than a dinner for two! The cost per report is less than one-tenth of a cent.

📊 NETWORK STATISTICS

Hedera Testnet Account:

Operator Account: 0.0.6255873
Topics Created: 2
Cost per Topic Creation: ~0.02 HBAR (~$0.002)
Cost per Message Submission: 0.00871297 ℏ (~$0.00086)
Transaction Finality: 3-5 seconds
Throughput: 10,000+ TPS
HBAR Price (at test time): $0.0989

Topic Statistics (Live Data from Hashscan):

TOPIC 1: REPORTS (0.0.7855971)
  Created:           February 7, 2026
  Total Messages:    78+ (active, receiving citizen reports)
  Auto-Renew Period: 90 days
  Status:            Active ✅
  Hashscan:          https://hashscan.io/testnet/topic/0.0.7855971

TOPIC 2: STATUS UPDATES (0.0.7855972)
  Created:           February 7, 2026
  Total Messages:    53+ (active, recording AI validations & status changes)
  Auto-Renew Period: 90 days
  Status:            Active ✅
  Hashscan:          https://hashscan.io/testnet/topic/0.0.7855972

🚀 PRODUCTION DEPLOYMENT

For production deployment (Hedera Mainnet):

Create Mainnet Account at https://portal.hedera.com
Fund Account with HBAR for transaction fees
Re-run Topic Creation script (hedera-playground.js) on mainnet — change Client.forTestnet() to Client.forMainnet()
Update Backend .env with mainnet credentials and new Topic IDs
Enable Monitoring via Hedera Mirror Node (mainnet)

Estimated Production Costs (based on real testnet data):

Account creation: $1-2 USD one-time
Initial funding: $50 USD (sufficient for ~58,000 report submissions at $0.00086 each)
Annual maintenance (national scale, 2,000 reports/month): ~$41/year

🔗 USEFUL LINKS

Hedera Documentation: https://docs.hedera.com
Hedera Portal: https://portal.hedera.com
Hashscan Explorer (Testnet): https://hashscan.io/testnet
Mirror Node API: https://testnet.mirrornode.hedera.com
HCS Documentation: https://docs.hedera.com/hedera/sdks-and-apis/sdks/consensus-service

📝 TECHNICAL NOTES

Why Not Use Smart Contracts?

We use HCS (Hedera Consensus Service) instead of smart contracts because:

✅ Lower cost ($0.0001 vs $0.001+ per transaction)
✅ Simpler integration (no Solidity code needed)
✅ Perfect for timestamped data logging
✅ Better for our use case (immutable records, not token transfers)

Why Hedera Over Other Blockchains?

✅ Fast: 3-5 second finality (vs 15+ seconds on Ethereum)
✅ Cheap: $0.0001 per transaction (vs $5-50 on Ethereum)
✅ Carbon Neutral: Hedera is carbon-negative
✅ Enterprise Grade: Used by Google, IBM, Boeing

🎯 IMPACT & TRANSPARENCY

By using Hedera blockchain, LafaekStreet ensures:

✅ Citizens can prove their reports were submitted and not ignored
✅ Government can demonstrate accountability and response times
✅ Media/NGOs can independently verify civic engagement data
✅ International Donors can audit infrastructure spending effectiveness
✅ Researchers can study civic participation patterns over time

Result: Trust through transparency, accountability through immutability. 🌟

📞 SUPPORT

For questions about the blockchain integration:

Check Hedera documentation: https://docs.hedera.com
Contact the development team

Built with Hedera for transparency, accountability, and trust in civic engagement. 🚀

🔗 HEDERA BLOCKCHAIN INTEGRATION - LAFAEKSTREET ​

📋 OVERVIEW ​

📁 Files in This Folder ​

🎯 WHY HEDERA BLOCKCHAIN? ​

Transparency ​

Immutability ​

Cost-Effective ​

Fast & Reliable ​

🏗️ HEDERA TOPICS ARCHITECTURE ​

Topic 1: Reports Topic ​

Topic 2: Status Updates Topic ​

📊 TOPIC CONFIGURATION ​

🔍 HOW IT WORKS ​

1. Citizen Submits Report ​

2. Blockchain Recording ​

3. Verification ​

🛠️ TOPIC CREATION SCRIPT ​

File: hedera-playground.js ​

Screenshot: Hedera Portal Playground ​

What the Script Does: ​

Full Script: ​

Output: ​

📸 LIVE EVIDENCE — REAL REPORTS ON BLOCKCHAIN ​

Reports Topic (0.0.7855971) — Citizen Report Data ​

Status Updates Topic (0.0.7855972) — AI Validation & Status Changes ​

Example Transaction Detail — Real Cost Breakdown ​

📈 BLOCKCHAIN DATA FLOW ​

💡 DATA STORED ON BLOCKCHAIN ​

Report Submission Payload: ​

Status Update Payload: ​

🔐 SECURITY & PRIVACY ​

Data Privacy: ​

Authentication: ​

Transparency vs Privacy Balance: ​

🌐 PUBLIC VERIFICATION ​

Method 1: Hashscan Explorer ​

Method 2: Hedera Mirror Node API ​

Method 3: In-App Verification ​

💰 COST ANALYSIS ​

Actual Transaction Costs (from real data): ​

Annual Cost Estimates (using real data): ​

📊 NETWORK STATISTICS ​

Hedera Testnet Account: ​

Topic Statistics (Live Data from Hashscan): ​

🚀 PRODUCTION DEPLOYMENT ​

🔗 USEFUL LINKS ​

📝 TECHNICAL NOTES ​

Why Not Use Smart Contracts? ​

Why Hedera Over Other Blockchains? ​

🎯 IMPACT & TRANSPARENCY ​

📞 SUPPORT ​

🔗 HEDERA BLOCKCHAIN INTEGRATION - LAFAEKSTREET

📋 OVERVIEW

📁 Files in This Folder

🎯 WHY HEDERA BLOCKCHAIN?

Transparency

Immutability

Cost-Effective

Fast & Reliable

🏗️ HEDERA TOPICS ARCHITECTURE

Topic 1: Reports Topic

Topic 2: Status Updates Topic

📊 TOPIC CONFIGURATION

🔍 HOW IT WORKS

1. Citizen Submits Report

2. Blockchain Recording

3. Verification

🛠️ TOPIC CREATION SCRIPT

File: `hedera-playground.js`

Screenshot: Hedera Portal Playground

What the Script Does:

Full Script:

Output:

📸 LIVE EVIDENCE — REAL REPORTS ON BLOCKCHAIN

Reports Topic (0.0.7855971) — Citizen Report Data

Status Updates Topic (0.0.7855972) — AI Validation & Status Changes

Example Transaction Detail — Real Cost Breakdown

📈 BLOCKCHAIN DATA FLOW

💡 DATA STORED ON BLOCKCHAIN

Report Submission Payload:

Status Update Payload:

🔐 SECURITY & PRIVACY

Data Privacy:

Authentication:

Transparency vs Privacy Balance:

🌐 PUBLIC VERIFICATION

Method 1: Hashscan Explorer

Method 2: Hedera Mirror Node API

Method 3: In-App Verification

💰 COST ANALYSIS

Actual Transaction Costs (from real data):

Annual Cost Estimates (using real data):

📊 NETWORK STATISTICS

Hedera Testnet Account:

Topic Statistics (Live Data from Hashscan):

🚀 PRODUCTION DEPLOYMENT

🔗 USEFUL LINKS

📝 TECHNICAL NOTES

Why Not Use Smart Contracts?

Why Hedera Over Other Blockchains?

🎯 IMPACT & TRANSPARENCY

📞 SUPPORT