Cryoseed steel Bitcoin seed phrase backup review

With self-custody being the topic of the day, let’s talk about the Cryoseed steel backup that was just recently released. Cryoseed sent me a review unit for free but I didn’t receive anything else for this review. I am publishing the stamped steel here. As of this writing there are 4 million sats attached to this seedphrase… but there is a passphrase also that would have to be brute forced.

This is my first experience with a one of those automatic punch tools. I’ve used washers with a hammer and stamp kit in the past and the automatic punch tool is much easier and faster. I was worried that the divets made in the steel are too light, but my understanding from other similar steel backup systems is that this is normal. As you can see in my review unit above, I made a mistake on the 4th word – I put two divets in one of the places to stamp a letter. I was moving too fast – let this be a lesson to anyone paying money for a steel backup… Be extra cautious as a mistake like this could render the steel plate useless.

Cryoseed is using the 2000 plus BIP39 words for this backup method. Using the first 4 letters of each, and in alphabetical order, 1. Abandon, through 2048. Zoo. In this manner you can use the placement of the divets to unlock each word and restore a wallet.

Overall feels really well made and I think the design of the plates sliding into each other and the little hole in it for locking is really smart.

I can confirm that with a lock in place the plates will not slide out from each other. This seems like an easy, and slim way to secure a seed phrase. Obviously you would want to feel good about the lock you use. I cannot speak to how well this would do in a fire but you can check out their specs for what they claim.

Cryoseed provides the two sliding plates, an automatic punch tool, papers for writing down the seed phrase using their system before you stamp it, a few stickers, and an instruction manual.

Pros to this steel backup system:

  • Easy to use
  • Easy to decipher
  • Comes with everything you need for a steel backup, except the lock which is optional
  • The punch tool seems to be high quality and is very accurate when punching a divet
  • Small footprint but still locks


  • Anytime you are ordering something that is known to be used for storing Bitcoin you have to be cautious with which information you are sharing, such as a home address. The folks at Cryoseed told me they delete user info, but you would have to trust that.
  • I don’t know how the numbers and dots would do in a fire situation.