The Keyois Capsule is a type of ‘physical bitcoin’

A physical bitcoin is a cryptographic key pair (or often just the secret key and address) put onto a physical medium. Before the Keyois Capsule a physical bitcoin was mostly a  secret key printed on plastic and affixed to what has always before been a physical coin. The first physical-bitcoin-coin was the Casascius coin, since then the world of physical bitcoin coins has blossomed as a fun part of the Bitcoin world.

Early physical bitcoins were made and assembled by the creator, which included them generating and affixing the secret key. In these cases the buyer has to trust the maker and their practices. To avoid the security risks inherent in this, BIP38 was created as a way to encrypt the secret key with a pass phrase.

Wallets can be made with BIP38 encryption and already existing wallets can be converted to BIP38. Here is a video explaining how to do it. But in essence use a secure computer and strong pass phrase with a site like or to create a BIP38 wallet. Dice and diceware can help you make a strong and random pass phrase.

Original postings:

The motivation to build the Keyois Capsule:
What’s wrong with my current cold storage method?

The original sales post about Keyois Capsule on

Who would want this?

Those with limited abilities for proper backup procedures. Good backups should always be in multiple locations and renters, those without trustworthy family, or those that live in a city might not have that option. Backups should be in multiple formats however if they are all in the same spot when disaster strikes then they may all be ruined.

Someone who doesn’t trust others or have places to leave their cryptocurrencies might have to keep their all stored data nearby.  These people might also want their funds to be able to survive a housefire or flood.

About the creation of the Keyois Capsule

For pictures please see this imgur album.

Inspired by other physical bitcoins but unsatisfied with their designs we reached out to others to make something new but didn’t hear back. So we decided to do it ourselves.  The project was started with only a vague idea and no experience in what would be needed to complete it.

The basic concept was centered around: being tamper evident, being fireproof, and the desire to use a tritium vial that was lying around. Tritium vials glow for years, even in total darkness, but fade away eventually. They still make an excellent decoration for the Keyois Capsule though.
The capsules were designed to last many decades but the tritium lasts two decades at most. Lab-created corundum was chosen as a second option. Chemically identical to the rubies and sapphires found in the ground, these gem centerpieces are a 9 on the Mohs hardness scale, almost as hard as diamond, and will keep their beauty forever.

It also remains that within the USA it’s illegal to repackage tritium into toys etc and sell them without rigorous and expensive testing.

The creator of the Keyois Capsule has created some amount of bad art previously but is not a professional artist. Subjects researched or encountered during the planning and execution of this project were mostly new and included:

CAD programs; 3D printing; metals & minerals; melting temperatures; hardnesses; metal plating; corrosion including galvanic corrosion (don’t keep the capsule in saltwater {or almost anything really} for long periods of time); powder coating; reflective coatings; temperature/liquid/gas indicating paint; Lichtenberg figures; RFID tags; glow in the dark paint; working with glass/concrete/clay; btctalkorg; laser cutting and engraving; sheet metal stamping; gimp photo-editing software; vector graphics; bad photography; fabrication; machine shops; screws; glues; customs and tritium rules in the usa; O-ring materials; X-rays; building a website ‘store’; and even some trigonometry.

Hope you enjoyed learning about the creation of the Keyois capsule, have a great day!