Chronos Fortress Smart Contract

A secure, time-locked Bitcoin vault system built on Stacks blockchain with multi-signature support, daily withdrawal limits, and emergency controls.

Overview

Chronos Fortress provides a sophisticated asset protection mechanism where users can create fortresses (vaults) with temporal barriers (time-locks), extraction limits (withdrawal caps), and sentinel authorization (multi-sig guardians). Perfect for securing long-term holdings, implementing corporate treasury controls, or establishing trustless inheritance mechanisms.

Core Features

🏰 Fortress Management

• Create Fortresses: Establish secure vaults with customizable parameters
• Temporal Barriers: Set time-locks preventing early withdrawals
• Cycle Thresholds: Implement daily/periodic withdrawal limits
• Operational Controls: Activate/deactivate fortresses as needed

🛡️ Security Features

• Multi-Signature Support: Require consensus from multiple sentinels for withdrawals
• Sentinel System: Authorize trusted guardians to approve extraction mandates
• Emergency Lockdown: Global protocol to freeze all fortress operations
• Input Validation: Comprehensive checks against malicious or malformed data

💰 Asset Operations

• Provision: Deposit STX tokens into your fortress
• Extract: Withdraw funds after temporal barrier expires (within cycle limits)
• Mandate System: Propose, endorse, and execute multi-sig withdrawals

Architecture

Data Structures

Fortresses Map

{
  architect: principal,          // Fortress owner
  reserves: uint,                // Current STX balance
  temporal-barrier: uint,        // Block height when withdrawals unlock
  cycle-threshold: uint,         // Maximum extraction per cycle (daily)
  extracted-this-cycle: uint,    // Amount withdrawn in current cycle
  last-extraction: uint,         // Last extraction cycle timestamp
  operational: bool,             // Active/inactive status
  sentinel-consensus: uint       // Required sentinel approvals
}

Extraction Mandates

{
  quantity: uint,                // Withdrawal amount
  beneficiary: principal,        // Recipient address
  endorsements: uint,            // Current approval count
  executed: bool,                // Execution status
  initiated-at: uint            // Creation block height
}

Usage Guide

1. Create a Fortress

(contract-call? .chronos-fortress construct-fortress 
  u14400        ;; temporal-lock (approx 100 days)
  u1000000      ;; cycle-threshold (1 STX per day)
  u2)           ;; sentinel-consensus (2 approvals required)

2. Deposit Funds

(contract-call? .chronos-fortress provision 
  u1            ;; fortress-id
  u10000000)    ;; quantity (10 STX)

3. Add Sentinels

(contract-call? .chronos-fortress commission-sentinel
  u1                                    ;; fortress-id
  'SP2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKNRV9EJ7) ;; sentinel principal

4. Simple Withdrawal (After Timelock)

(contract-call? .chronos-fortress extract
  u1            ;; fortress-id
  u500000)      ;; quantity (0.5 STX)

5. Multi-Sig Withdrawal Process

Step 1: Initiate Mandate

(contract-call? .chronos-fortress initiate-extraction-mandate
  u1                                    ;; fortress-id
  u1                                    ;; mandate-id
  u2000000                              ;; quantity
  'SP2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKNRV9EJ7) ;; beneficiary

Step 2: Sentinels Endorse

(contract-call? .chronos-fortress endorse-extraction-mandate
  u1            ;; fortress-id
  u1)           ;; mandate-id

Step 3: Execute (After Required Endorsements)

(contract-call? .chronos-fortress execute-extraction-mandate
  u1            ;; fortress-id
  u1)           ;; mandate-id

Configuration Functions

Adjust Temporal Barrier

(contract-call? .chronos-fortress adjust-temporal-barrier
  u1            ;; fortress-id
  u28800)       ;; new-temporal-lock (approx 200 days)

Adjust Cycle Threshold

(contract-call? .chronos-fortress adjust-cycle-threshold
  u1            ;; fortress-id
  u2000000)     ;; new-threshold (2 STX per day)

Toggle Operational Status

(contract-call? .chronos-fortress toggle-fortress-operational-status
  u1)           ;; fortress-id

Read-Only Functions

Query Fortress Details

(contract-call? .chronos-fortress get-fortress-details u1)

Check Reserves

(contract-call? .chronos-fortress get-fortress-reserves u1)

Check Accessibility

(contract-call? .chronos-fortress is-fortress-accessible u1)

Get Remaining Daily Limit

(contract-call? .chronos-fortress get-remaining-cycle-threshold u1)

List Architect's Fortresses

(contract-call? .chronos-fortress get-architect-fortresses 'SP2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKNRV9EJ7)

Error Codes

Code	Constant	Description
u100	err-architect-only	Only contract architect can perform this action
u101	err-access-denied	Caller not authorized for this fortress
u102	err-fortress-sealed	Fortress locked or inactive
u103	err-insufficient-reserves	Not enough balance in fortress
u104	err-invalid-quantity	Invalid amount specified
u105	err-fortress-exists	Maximum fortresses reached
u106	err-fortress-not-found	Fortress ID doesn't exist
u107	err-extraction-limit	Daily withdrawal limit exceeded
u108	err-cooldown-active	Cooldown period still active
u109	err-invalid-temporal-lock	Invalid timelock value
u110	err-sentinel-exists	Sentinel already commissioned
u111	err-not-sentinel	Caller is not an authorized sentinel
u112	err-invalid-input	Invalid input parameter

Security Considerations

⚠️ Important Notes

1. Temporal Barriers Are Immutable Once Passed: While you can extend a timelock, you cannot shorten it
2. Cycle Limits Reset Daily: Approximately every 144 blocks (~24 hours)
3. Sentinel Trust: Choose sentinels carefully - they have significant authority
4. Emergency Lockdown: Contract architect can freeze all operations globally
5. No Recovery Mechanism: Lost private keys mean lost access to fortresses
6. Input Validation: All user inputs are validated before processing

Best Practices

• Use Multi-Sig for Large Amounts: Don't rely on single-key control for significant holdings
• Test with Small Amounts First: Verify timelock and limit configurations work as expected
• Document Sentinel List: Keep secure records of authorized sentinels
• Regular Security Audits: Review fortress configurations and sentinel permissions periodically
• Backup Configuration: Store fortress IDs and configuration parameters securely

Use Cases

1. Personal Savings Vault

Lock away savings with a time barrier to prevent impulsive spending, with daily withdrawal limits for controlled access.

2. Corporate Treasury

Implement multi-signature requirements for company funds with department-level spending limits and executive oversight.

3. Inheritance Planning

Create time-locked vaults with trusted family members as sentinels, ensuring smooth asset transfer.

4. Escrow Services

Hold funds in neutral fortresses requiring multi-party approval for release.

5. DCA Protection

Prevent emotional trading by time-locking investment capital with gradual extraction limits.

Technical Specifications

• Blockchain: Stacks (Bitcoin L2)
• Language: Clarity
• Token: STX (Stacks native token)
• Block Time: ~10 minutes (Bitcoin-anchored)
• Cycle Duration: ~144 blocks (~24 hours)
• Max Fortresses per Architect: 50

Development & Testing

Prerequisites

• Stacks CLI (clarinet)
• Stacks wallet
• Testnet STX tokens

Deployment

clarinet deploy chronos-fortress

Local Testing

clarinet test