The Super-Powers of Anti-Theft Multi-Shares Protection

Anti-theft crypto seed backup solution

Key takeaways:

- Seed phrase metal backups provide robust physical protection and multiple shares resilience for crypto seeds.
- To achieve greater resilience, seeds can be split with a 24-word BIP39 or with SLIP39 Shamir Secret Sharing.
- A 24-word BIP39 seed split protects against loss and theft.
- Shamir Secret Sharing offers advanced encryption for each share of a seed, with each share encrypted independently.
- Hodlrs are optimised for engraving crucial identification information about the recovery scheme setup and the seed name, deep into the metal.


As we transition towards a digitised economy, securing access to digital assets is of paramount importance. This article discusses the benefits of splitting a 24-word BIP39 seed, the power of multi-share mnemonic seed phrase protection with Shamir Secret Sharing, and the importance of becoming your own bank, with the right tools to cater every needs.

Resilient Crypto Security: The Power of Multi-Shares Crypto Metal Seed Phrase Protection

In the crypto world, secure access to your digital assets is paramount. As we progress towards a more digitised economy, safeguarding these assets from loss and theft is a growing concern. 

The act of splitting your seed can be done in two ways: by manually splitting a 24-word BIP39 seed, or either through a SLIP39 Shamir Secret Sharing compatible hardware wallet, which automatically generates up to 16 shares (Trezor Model T).

Each Hodlr caters to different security needs, providing you with the flexibility to select a recovery scheme that best suits your requirements. Our product range are optimised for the following multi-shares security schemes SPLIT (2-of-3), SHAMIR (2-of-3), SHAMIR (3-of-5), and SHAMIR (X-of-Y), each offering varying degrees of protection against hacking, physical damage, loss, and theft.

Gaining resilience with a BIP39 24 words seed split

When it comes to creating redundancy and resilience in seed security, splitting a 24-word BIP39 seed is a powerful tool at your disposal. This process involves distributing the 24 seed words across multiple shares, ensuring that each share holds a unique set of words. This redundancy creates a safety net, where the loss or theft of one share doesn't compromise the entire seed.

The process is straightforward. Using our multiple shares splitting protocol, you can manually split your 24-word BIP39 seed across multiple Hodlrs. These individual Hodlrs then each hold a share of the seed. Even if one share is compromised, the thief will only have a part of the seed, essentially leaving them with a puzzle with missing pieces.

For example, with a 2-of-3 recovery scheme, your seed is split across three Hodlrs. Each Hodlr holds a unique set of seed words, and you need at least two to fully recover the seed. This redundancy provides a robust layer of protection against theft and loss.

By using a 24-word BIP39 seed split, you're not only protecting against theft, but also loss. Even if one share goes missing or is destroyed, the remaining shares can recover your seed, ensuring your digital assets are safe.

In this era of digital wealth, resilience is critical. With a 24-word seed split, you're equipping yourself with a robust and flexible security setup that can withstand a range of threats. In other words, you're taking a significant step towards ultimate self-custody and peace of mind.

Is a 24 words seed split secure?

In some scenarios, splitting your seed using the manual 24 words seed split method might not provide sufficient security. With one share, enough information is available to infer that eight words are missing and where they are positioned. This reduces the security of one share to an 88bits encryption, compared to the 256bits of a whole 24-word seed.

If a thief finds a 24-word split share, the security comes down to guessing eight words. For this reason, the SPLIT 2-of-3 recovery scheme should never be used with less than a 24-word seed without employing Shamir Secret Sharing.

According to Ian Coleman, brute-forcing a 24-word BIP39 mnemonic split with only one share could take up to 3’830’854 years for a single CPU. For most people, this time frame would provide enough opportunity to react if one share is compromised.

If you believe you could be targeted by such a resourceful crypto thief, it would be wise to reassess your security strategy from scratch and certainly consider using a Shamir Secret Sharing security scheme.

Understanding the power of multi-share mnemonic seed phrase protection with Shamir Secret Sharing

The concept of multiple-share seed protection is simple yet incredibly powerful. By splitting your seed into several shares, you're adding layers of resilience to your crypto security setup.
Another method to achieve it, based on the principle of Shamir Secret Sharing, allows for a 2-of-3, 3-of-5, or even x-of-y recovery threshold, with up to 16 shares.

The strength of the Shamir Secret Sharing (SSS) scheme lies in its ability to provide an advanced level of encryption for each share of a mnemonic seed phrase. When using SSS, each share is independently 128bits encrypted, ensuring it cannot be brute forced at all and that no single share reveals any information about the others. This feature makes SSS a powerful tool in securing your digital assets.

Here's how it works: A mnemonic seed phrase is divided into multiple shares using the SSS algorithm. This process is automatically done by a compatible hardware wallet (Trezor Model T). Each of these shares is encrypted independently and can be stored in a separate Hodlr. 

For instance, in a 3-of-5 SSS scheme, you could distribute the shares across five different Hodlrs. Even if a thief manages to steal one or two Hodlrs, they will be left with encrypted shares that give away no information about the seed phrase. To reconstruct the seed, at least three shares are needed, hence the name 3-of-5.

The 128bits encryption of each share is equivalent to a 20-word Shamir share, providing a high level of security that ensures the integrity of each share. This encryption level means that each share, even if intercepted or stolen, remains secure and gives away no information about the overall seed or the other shares.

By employing Shamir Secret Sharing in your seed security strategy, you are adding a robust layer of protection that guards against both theft and loss. It's an advanced strategy for those seeking the utmost security for their digital assets.

Naming your Hodlrs and adding their multi-shares parameters

To easily identify which Hodlr holds which seed, we designed a dedicated seed name area on all our products. This ID zone is made to engrave the name of your seed deep into the metal so it can never be inverted with another share. It is important to note that for any multi-shares setup all Hodlrs holding shares of the same seed must have the same name.

All Hodlrs are optimised for use with 24 words seed split or Shamir Secret Sharing. In addition to the seed name, crucial identification information about the recovery scheme setup can be engraved onto the metal. A dedicated "SOT" parameters area on all Hodlrs is reserved for engraving seed parameters such as the total number of shares, share number, threshold and, of course, the seed name. 

What are SOT Parameters

Share = number of the share, Of = total number of shares, Threshold = minimal number of shares required to recover the full seed.

Advice: Remember, the security of your digital assets is not just about preventing theft, but also ensuring you can recover your assets if a share is lost or damaged. Make sure to store your Hodlrs in separate, secure locations.

The responsibility of becoming your own bank

The freedom that comes with self-custody of your digital assets is liberating yet comes with significant responsibility. Your digital assets' security should be as resilient as possible. To achieve this, your seed phrase backup should be non-custodial, kept secret and under your control, kept in 100% offline cold storage, stored in a solid tangible object, resistant to physical damages, permanently engraved, safe to recover, and of course, distributed in multiple shares across different storage locations.

The power of 3-pack bundles offers

Our Hodlr One and Hodlr Disks 3-pack bundles allow you to split a 24-word seed into three shares, adding an extra layer of security to your seed security. Both are compatible with Shamir Secret Sharing, with Hodlr One prepared for up to 5 shares and Hodlr Disks ready for up to 16.
If freedom comes with great responsibility, we made sure that now, it also comes with great tools to achieve it securely. Our multi-packs are precisely designed to be the security foundation of your crypto, bringing you peace of mind on your self-custody journey.



The world of digital assets comes with significant responsibility. Ensuring their security isn't just about preventing theft; it's also about having a reliable recovery mechanism in case a share is lost or damaged. Both 24-words Seed Split and Shamir Secret Sharing offer layers of resilience to allow you to embrace the freedom of self-custody with the security and peace of mind that your digital assets require.

Ensure the longevity and resilience of your crypto, making sure no-one except you and those you choose can access them. Remember, with great power comes great responsibility - and with Hodlr, great tools to handle it.

Note that if you need any help choosing or understanding more about the anti-theft potential of our products, our premium tech support at Hodlr is always ready to assist. Reach out to us for guidance and support. We're committed to making your journey towards self-sovereignty as smooth as possible.



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