Satodime — Why and how to use your bearer crypto card

This article is the starting point of the Satodime series which will show you how to use the Satodime bearer crypto card as well as the Satodime tool. Today, we will explain you what Satodime is and how to store your favorite cryptocurrency within.

Table of content

  1. Introduction
  2. Usecases
  3. Prerequisites
  4. Create a new vault == SEAL
  5. Store your cryptocurrency == LOAD
  6. Check the balance and the state == VERIFY
  7. Retrieve the private key == UNSEAL
  8. Wipe out the vault == RESET
  9. Conclusion

Introduction

According to the website, Satodime is a bearer chip card that allows you to exchange crypto assets like any banknote. Safely pass it along multiple times thanks the secure chip, unseal anytime with ease. Trustless, easy to verify and completly secure.

You can imagine a Satodime as a bank vault; you can deposit some valuable things within the vault and only the key holder can open it.

Satodime works like that with the only exception that the key to open the vault is not held by the holder of the card. It’s held by the card itself thanks to the secure chip.

With a Satodime card, you can physically transfer #Bitcoin, #Litecoin, #BitcoinCash, #Ethereum or any other #ERC20 tokens (including #NFTs) from one user to another (hand-to-hand), while still remaining secure, without the need to trust a third party.

Long story short, it’s basically a disposable hardware wallet that can be used like cash. Use it accordingly.

Usecases

To show you the potential of Satodime, let’s dive into some use cases:

  • Buy goods

You want to buy the new Tesla using Bitcoin. You grab your Satodime, seal a new Bitcoin vault, write down the BTC address and load 1 BTC to it. Then, you go to the car dealer and begin negotiations. The dealer is asking for 1.25 BTC for this beautiful Ludicrous P100D. You accept the deal and send 0.25 more BTC to your Satodime vault using your favorite Bitcoin client. You grab your mobile phone, scan the Satodime using NFC and show the sealed vault to the car dealer. He can verify that the Bitcoin vault is sealed and full of 1.25 BTC. You shake hands and give him the card. You grab the car and leave the showroom peacefully and silently. SEAL — LOAD — VERIFY

Satodime allows you to buy goods.
  • Exchange art (NFTs)

You are an NFT (Non Fungible Token) artist and are ready to launch your new collection on OpenSea. You would like to promote your collection of Bored Punk Farmer in a new and fashion way. You grab your Satodime, seal a new Ethereum NFT (ERC-721) vault, write down the ETH address and load 1 NFT to it. You can now airdrop your Satodime through your social medias. Winners who will receive the card, physically, will be able to verify the NFT vault and optionaly unsealed it to recover the Etherem wallet’s private key. SEAL — LOAD — VERIFY

  • Cold storage for crypto-currencies

You want to “orange pill” your friends and let them discover Bitcoin and crypto-currencies, you can gift them a Satodime. You grab your Satodime, seal a new Bitcoin vault, write down the BTC address and load 0.0001 BTC to it. Gift the card to your friend and tell him/her, he/she can verify the balance of the wallet using his/her mobile phone. Awsome!

No PIN code required, no seed generation, no complexity. Just a chip card, loaded with some Bitcoin sats that you can pass along, multiple times, trustless. SEAL — LOAD — VERIFY

Stacking sats with your Satodime.

Prerequisites

Ok, how to do it?

  1. Grab a Satodime bearer crypto card 💳 on the official Satochip webshop.
  2. Optionally: grab a chip card reader to be able to setup your Satodime on your computer.
  3. Download and install the Satodime-Tool, the all-in-one application that will allow you to create and manage wallets/vaults within your card:

Create a new vault = SEAL

In this example, we will create a Bitcoin vault in our Satodime. While running the Satodime-Tool, you will see that you can create up to 3 vaults using a single card. Meaning you can store up to 3 different cryptocurrencies.

So far, Satodime supports:

  • Bitcoin ($BTC)
  • Litecoin ($LTC)
  • Bitcoin Cash ($BCH)
  • Ethereum ($ETH)
  • The ERC-20 and ERC-721 tokens (NFT).
Satodime-Tool — Interface.

To create a new vault, simply click on “Seal key!”.

Seal key! will open a new menu.

The “Seal key!” menu will pop up. Private/public keypairs stored on the Satodime are always generated randomly inside the secure chip. As long as the keyslot is sealed, nobody has access to the private key. To prove that the private keys were not pre-generated during manufacturing and that no backdoor was inserted in the firmware, the user is prompted for a 64-hex random value during the sealing process. This random input is used to provide entropy during the key generation process. When the keyslot is unsealed and the private key is revealed, the entropy data (including user input) is provided and allows to ensure that the key generation process was indeed random.

Let’s generate a random entropy by clicking on the “Generate” button.

Satodime’s entropy is co-generated by the user and the chip card.

Then you can select the “Asset” and “Coin” type. Here we choose to create a vault (wallet) to store our Bitcoin.

Note: Satodime does also support TestNet network.

Specify the asset and coin type.
Satodime — Seal a new vault. A new wallet will be generated.

Below the ‘Card info’ tab, the status and info of each keyslot is provided. Remember that a Satodime can have up to 3 available keyslots, and each keyslot can be in the ‘Uninitialized’, ‘Sealed’ or ‘Unsealed’ state.

If a keyslot is sealed or unsealed, more details are provided by clicking on the ‘More details’ button for the corresponding slot. Available info includes the asset type, the blockchain used and the balance available for the associated address.

Store your cryptocurrency == LOAD

You have now created a Bitcoin wallet. The Satodime-Tool allows you to get the public information of this freshly generated wallet.

In this example, the wallet’s public address is 18LbwEtgYvT8uwi6iZGX31eEe7yQPmvUzJ.

The vault #0 aka “Key #0” is in a “Sealed” mode meaning nobody has never had access to the private key of this wallet. You can safely load your Bitcoin onto this address.

Satodime — The vault #0 aka “Key #0” is in a “Sealed” mode.

If you want to get more details about this sealed vault, simply click on the button “More details”.

The details tab will provide you the following informations:

  • The status of the keyslot : ‘Sealed’ => ‘Unsealed’ => ‘Uninitialized’;
  • The public key (PubKey) of the wallet;
  • The asset type : ‘Coin’, ‘Token’, ‘ERC20’, ‘NFT’, ‘ERC721’;
  • The blockchain used for such wallet;
  • And the addresses.
Satodime — Details tab for keyslot #0

For convinience use, you can show the QR code of the address. It’s very useful if you want to load some Bitcoin into this freshly generated wallet.

Satodime — QR code of the freshly generated Segwit Bitcoin address

Check the balance and the state == VERIFY

Each keypair is generated inside the secure chip and can be in any one of 3 states at any time:

  • Uninitialized: the keypair has not been generated yet;
  • Sealed: the keypair has been generated securely inside the chip;
  • Unsealed: the private key has been revealed.

In this example, you can see that the keyslot #0 is still “Sealed” and the keyslot #1 is “Unsealed” while the keyslot #2 is “Uninitialized”.

Satodime — An example of the different Keyslot status.

If a keyslot is in the “Sealed” status and the balance shown a positive amount of cryptocurrency, you can safely accept, share, buy, get the Satodime. It means this particular vault contains Bitcoin and the private key has never been redeemed.

Retrieve the private key == UNSEAL

If you want to retreive the private key of a specific keyslot, you can unseal the keyslot at anytime. This action is not reversible.

Unsealing a keyslot will ask the secure chip to expose the private key.

Satodime — Warning message that explains the private key exposure.

When a keyslot is unsealed, the private key is made available to the user and can be recovered by clicking on the ‘more details’ button of the corresponding slot.

An unsealed Bitcoin vault.

Once the private key is unsealed, it is no longer protected by the secure chip and any asset associated with the corresponding address should be transferred immediately to a new address. This is generally done by ‘sweeping’ the private key and many wallet provides this option (e.g. Electrum and Metamask).

YOU SHOULD NEVER ACCEPT A SATODIME FROM SOMEONE IF A KEYSLOT IS UNSEALED!

Details about an unsealed keyslot.

Wipe out the vault == RESET

One of the big advantage of your Satodime bearer crypto card is that you can reuse it indefinitely. For a given keyslot, the transition between status follows always the same cycle: ‘Uninitialized’ => ‘Sealed’ => ‘Unsealed’ => ‘Uninitialized’ => … This is huge, right ?

Once a keyslot is unsealed and any asset has been transferred, you can reset the slot to return it in its ‘Uninitialized’ state and start a new cycle again.

Be sure you have backed up :

  • The public key (pubkey) and the wallet address
  • The private key

Because this action will reset the corresponding private key. Once reset, all the corresponding data will be deleted.

And there you go, the keyslot #0 is now free of use. Slot’s state is “Uninitialized” and you can use it again.

Satodime main menu.

Conclusion

There is nothing like Satodime on the market!

Satodime allows you to physically store, verify and exchange cryptocurrencies and other tokens such NFT.

Satodime is:

  • Multi-crypto: your Satodime card supports many cryptocurrencies. You can generate private keys for Bitcoin, Litecoin, Bitcoin Cash, Ethereum and the ERC20 tokens. The card supports ERC20 and ERC721 based tokens and many more to come… You can even store your favorite #NFT.
  • Multi-vault: you can generate up to 3 different vaults. It allows you to manage multiple private keys at once. For example, you can safely store some Bitcoin, some Ethereum and your favorite shitcoin in one single Satodime bearer crypto card. The Satodime supports the MainNet and the TestNet coins and tokens.
  • Secure: your Satodime is not only a storage device. It embbeds an EAL6+ certified smart chip that acts as a secure element (SE) to handle your keys (public and private) with care. Thanks to cryptography, your privates keys and sensitive information are safely isolated within the secure chip and never leave it.
  • Trustless: private keys are stritcly sealed within the secure chip. You don’t know the keys until you redeem the key slot. The color of the key slot turns from green to red when it’s unsealed. Just like a fiat bill, it has never been so easy to safely transfer cryptocurrencies hand-to-hand.
  • Reusable: no need to break the device to use it again. You can redeem the private key and reset the vault again and again.
  • Customizable: just like the Satochip hardware wallet, your Satodime card can be customized to fit your need. You can, for example, print your favorite #NFT on your Satodime and load it. Amazing!

More information about Satodime

💮 Join us on Telegram
🐦 Join us on Twitter
👾 Check out our website
🔨 Take a look at our GitHub

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Satochip

Open source and affordable hardware wallet on smart card. More information on https://satochip.io — Follow us on Twitter : @SatochipWallet