Satodime

Satodime Overview

Satodime is a bearer crypto card made by Satochip S.R.L., a company based in Belgium. It is described by the manufacturer as a giftable cold storage solution, designed to transfer cryptocurrency hand-to-hand in the same way a paper bill changes hands.

The card uses an EAL6+ certified secure element chip to generate and store private keys. The chip includes a co-processor and tamper-proof memory. There is no PIN code and no seed phrase. The physical holder of the card is the owner of the private keys at any given time.

A single card can hold up to three separate vaults, referred to as keyslots, allowing up to three different cryptocurrencies to be stored independently on one card at the same time. Each vault has three possible states: sealed, unsealed, or empty. While sealed, the private key remains hidden inside the chip. Unsealing a vault reveals the private key so it can be exported and used in another wallet, for example to sweep the funds elsewhere.

A Satodime card is paired with a specific device on its first use. Only the legitimate owner can perform sensitive operations such as unsealing a vault and revealing a private key. A separate person can scan the card to check its balance without being able to access the funds. Each card includes a cryptographic authenticity mechanism, verified through a digital certificate checked against a trusted PKI, to confirm the card is genuine.

The card supports Bitcoin, Ethereum, ERC-20 tokens, Litecoin, Bitcoin Cash, and Polygon, and can also store NFTs. Both MainNet and TestNet are supported.

The card connects to a computer through a smart card reader or to a phone via NFC. The Satodime mobile and desktop applications are available for iOS, Android, Windows, Linux, and macOS.

All firmware and software, including the mobile application, are released as open source under the AGPLv3 license. The source code is published on the manufacturer’s GitHub repository.