$5 Dollar Wrench Attack Explored

$5 Wrench Attacker
Protect Against "$5 Dollar Wrench Attack" Scenarios

Whether you're a seasoned Bitcoin pleb or a first-time Bitcoin user, the concern of physical attackers has probably crossed your mind. Let's discuss how you can better protect yourself from the "$5 wrench attack."

Theya is the world's simplest Bitcoin self-custody solution. With our modular multi-sig vaults, you decide how to hold your keys.

Whether you want all your keys offline, shared custody with trusted contacts, or robust mobile vaults across multiple iPhones, it's Your Keys, Your Bitcoin.

Download Theya on the App Store.

What Is the $5 Wrench Attack?

A "$5 wrench attack" is a term used in the context of Bitcoin security to describe a scenario where physical force or coercion is used to steal someone's digital assets rather than employing hacking techniques. It illustrates how a $5 wrench could be used to forcibly extract or reveal someone's seed phrase rather than trying to crack Bitcoin's secure encryption.

The concept of a wrench attack highlights a vulnerability of Bitcoin; no matter how secure a wallet's cryptography is, it can be rendered useless if an attacker can simply threaten a wallet owner until they agree to hand over or transfer their Bitcoin.

Are $5 Wrench Attacks a Real Threat?

While predominantly a theoretical scenario, it does pose a real threat to Bitcoin investors. The potential for an attack underscores the importance of employing secure operational security in your Bitcoin setup and ensuring your personal identity and physical location are not easily linked to your holdings to avoid becoming a potential target of such physical threats.

Protecting Yourself From A $5 Wrench Attack 

There are many non-mutually exclusive solutions to upgrade your Bitcoin security and lower your risk of a $5 wrench attack. This can range from extra security measures to increasing plausible deniability.

  • Practice Privacy: Keep your bitcoin holdings private and avoid sharing information about your investments publicly, which may expose you to digital threats and physical attacks. In other words, don't unnecessarily make yourself a target without proper security measures.
  • Home Security: Improve your physical security measures at home or wherever you store your seed phrase and hardware devices. This could include better locks, security cameras, alarm systems, or safes to deter potential thieves and attackers.
  • Decoy wallet: With a singlesig setup (one hardware device), create a secondary wallet with a smaller amount of Bitcoin that you can reveal if coerced, satisfying the attacker while keeping your main cold storage funds secure. This can be accomplished by creating a "hidden wallet" with a passphrase. Additionally, Coldcards offer BIP85 functionality. This allows you to create "child" seed phrases and wallets that one could use as a decoy.
Use caution when adding additional layers of security with "hidden wallet" passphrases, as over complication can cause funds to be lost due to user error. Read more.
  • Geographical Separation: Store your seed phrase(s) in secure locations, separated from your hardware wallet(s), inside or outside your home. This reduces the ability of an attacker to obtain your 12-24 recovery words. With a multisig vault setup, you could also geographically separate your hardware devices.
  • Multisig: Implement a multi-signature wallet where multiple private keys are needed to authorize access or move your Bitcoin. By employing this strategy, even if an attacker gains access to one key, the bitcoin held in a multisig vault remains protected since the attacker would require the additional private keys. This is a common storage method, but DIY multisig can be intimidating for non-technical users. Theya offers collaborative 2-of-3 multisig vaults and singlesig vaults, offering modular self-custody to fit your bitcoin self-custody needs.
  • Multisig Shared Custody: Use a service or arrange with trusted individuals to require multiple parties to access your funds. This distributes risk and makes it harder for an attacker to access your funds through coercion. Theya allows you to assign a cosigner to your multisig vault, making it easy to share custody with family, partners, financial advisors, etc.

Ultimately, there is no one-size-fits-all solution, and the above strategies can be combined in various ways depending on your preferences, circumstances, and risk level. This enables you to significantly enhance your protection against a $5 wrench attack and other threats.

Protect Your Bitcoin With Theya

Here's one example of how a user could take advantage of Theya's modular self-custody solution to protect their bitcoin:

  • A mobile key vault for pocket money.
  • A singlesig vault for cold storage (limited access).
  • A singlesig vault for cold storage (regular access).
  • A multisig vault using any combination of the devices mentioned above.

Theya Mobile Key Vault

This vault is secured by the secure enclave on your phone, essentially making it an on-the-go "hot wallet." It could hold a small amount of Bitcoin intended for easy movement and spending. Due to the ease of signing transactions with FaceID or passcode, it's the most vulnerable to a $5 wrench attack. Think of it as "pocket money".

Theya Singlesig Vault(s)

A singlesig vault is secured by one hardware wallet (signing device), backed with a seed phrase, and paired with Theya for simplified fund management. These are ideal for significant bitcoin holdings intended for future payments or consolidating funds before moving into multisig (practicing proper UTXO management for long-term storage).

With Theya, you can easily create singlesig vaults for different purposes, where the amount and level of access to funds is at the user's discretion. For example:

With a singlesig vault intended to consolidate funds, you don't need frequent access to the hardware device for signing and sending transactions; the device itself can be securely stored away. In this scenario, the vault in your Theya app can still receive funds, monitor incoming transactions (via mempool.space), and check balances.

Theya 2-of-3 Multisig Vault

For long-term storage (4-10+ years) of significant holdings, a multisig vault provides enhanced security by removing a single point of failure.

With Theya, you hold two keys, with the option to invite a cosigner, and Theya holds a third key for recovery purposes. So, if one of your keys is compromised, your funds are still safe. Your multisig keys can be created with the same devices used in your singlesig vaults mentioned above.

Protect Yourself With Modularity & Diversity of Hardware

Theya is compatible with popular hardware devices and offers unparalleled modularity for self-custody. You can set up one bitcoin wallet, separate wallets, and elevate your security to include a collaborative multisig vault—all in one app

Explore Theya and schedule a free consultation to learn how we can help keep your bitcoin stack intact.