Splitting a Recovery Phrase Across Two Locations Safely
Naive splitting makes a phrase easier to break, not harder. Three approaches that work and one that does not.
Gabriel Mas ·
Storing a recovery phrase in one place risks loss. Splitting it badly risks both loss and theft. Here is the difference.
The approach that does not work
Writing words one to twelve in one place and thirteen to twenty four in another. This feels like splitting and is not.
Anyone finding half the words has reduced the search enormously. The remaining difficulty is far smaller than it appears, and the scheme also doubles the chance of losing access, because either half being destroyed loses everything.
Worse security and worse reliability at once.
Approach one: full copies in separate places
Two complete copies in two locations, each physically secure. Loss requires both to be destroyed; theft requires only one to be found.
This trades theft risk for loss protection, and for most people loss is the larger risk. It is the right default.
Approach two: a passphrase
Most wallets support an additional word of your own choosing on top of the recovery phrase. The written phrase alone opens an empty wallet; phrase plus passphrase opens the real one.
Store the phrase in two places and keep the passphrase elsewhere, including in your memory. Someone finding the written words gets nothing.
Forgetting the passphrase loses everything, so it must also be written somewhere, in a different place from the phrase.
Approach three: proper secret sharing
Schemes that split a secret into several shares, any two or three of which reconstruct it, while any single share reveals nothing.
This is mathematically sound and supported by some hardware wallets directly. It is more complex to operate and the complexity itself is a risk if nobody else understands the arrangement.
Choosing between them
One person, moderate amount: two full copies. One person, larger amount: two copies plus a passphrase. A company or an estate: a sharing scheme, documented.
The step everyone forgets
Testing the restore. A backup that has never been used is an assumption.
Do it once on a wallet holding very little. Exchanges that let you practise with a small amount first make that rehearsal cost almost nothing.
The honest alternative
For many people, a licensed custodian is a better answer than any of this. Collect & Exchange holding the keys is a different risk, not a larger one, and a platform where each step tells you what happens next is a reasonable place to keep the portion you are not ready to manage yourself.