Introduction

TimeCapsule is a tool designed to securely store passphrases to Bitcoin wallets and other sensitive accounts using time-lock puzzles. This tool ensures that passphrases are accessible only after a predetermined period, providing a secure method for inheritance and delayed access to digital assets.

Features

• Secure Passphrase Storage: Ensures that the passphrase is locked and can only be accessed after a specific amount of computation has been performed (computational time-lock).
• Cryptography: Utilizes AES encryption and time-lock puzzles based on repeated squaring to secure data.
• Customizable Delay: Users can set a specific delay period, after which the passphrase can be decrypted. Users can and should adjust speed based on the system they expect to either be attacked on or solved on (taking into consideration threat model). Speed was baselined on 3.4 GHz Intel system. Double it if in doubt.

Support for Windows, macOS, and Linux

After purchase, TimeCapsule can be downloaded via your Account Page.

Creating a New TimeLock Puzzle

1. Keep in mind the most secure way to use TimeCapsule is from a disconnected machine that you then wipe
2. Run the code and select option 1 to create a new puzzle.
3. Enter the desired time in seconds that the puzzle should remain locked, generally double the time for the most advanced threats.
4. Wait as the puzzle is "charged".
5. Enter the password that you want timelocked in the puzzle.
6. The script will generate a puzzle and save it in a file named puzzle.json.
7. Save the puzzle.json to secure offline storage

Solving a Puzzle

1. Restore the saved puzzle.json file from secure offline storage
2. Rerun and select option 2 to crack the current puzzle saved as puzzle.json in the same directory.

How It Works

TimeCapsule encrypts a given passphrase using AES encryption. The encryption key is locked within a time-lock puzzle, which requires performing a computationally intensive task that cannot be sped up by parallel processing. This task involves repeatedly squaring a number modulo a large number, a process that must be repeated a specific number of times determined by the desired delay.

Security Considerations

• Keep the puzzle.json file secure to prevent unauthorized access.
• Store the puzzle.json in a tamper resistant bag to detect access.
• Be prepared to move the funds through another means if TimeLock puzzle is compromised.