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Cold storage setup

We recommend this method for advanced users holding a large amount of Minima.

Minima transactions require recent coin proofs of your funds and up-to-date data from the chain. This requires a node to be online as much as possible.

However, to create a truly secure solution it is imperative that the private keys are NEVER online EVER. This can be achieved by using an offline device to sign your transactions.

This setup involves:

  1. Creating your node for the first time on an offline device,
  2. wiping your private keys from the node,
  3. backing up and restoring the keyless backup to an online device,
  4. restoring the private keys to the offline device
  5. locking the node with a password - this prevents you needing to input the seed phrase to unlock and sign your transactions.

You will be able to see your wallet addresses and receive funds as normal on the online device.

To transact:

  1. Create your transactions on your online device
  2. Export the transaction and transfer it to the offline device
  3. Sign the transaction on your offline device, providing the password used to lock the node
  4. Export the signed transaction and transfer it to the online device
  5. Post your transaction on your online device

Setup​

You will need a USB key and 2 devices:

Device 1: Offline node
No internet connection/bluetooth/nearby sharing should be enabled. This device will hold your private keys and will be used to sign your transactions offline.

Device 2: Online node
Connected to the internet, this node will not hold any private keys and will only be able to send a transaction that has been signed by the offline device. This device will keep track of your coins and can be used to receive funds as usual.

On Device 1 - The offline node​

  1. Set up device 1 so that it can start a Minima node.
  • Android: download the latest app
  • Docker: ensure you have docker installed
  • Manual on desktop: ensure you have java installed and the minima.jar downloaded

  1. Turn off the internet connection/bluetooth/nearby sharing and disable the WiFi, this device should never be connected to the internet again.

  2. Start a new Minima node. Your private keys will be generated but as it is not connected to the internet, it will NOT connect to the chain.

  3. Using the command line interface where the Minima logs are running or the Docker Terminal, run the vault command to view your 24-word seed phrase and the seed itself. If using a phone as your offline device, you can also go to the Vault page and view your seed from the menu there.

Example:

vault
{
  "command": "vault",
  "status": true,
  "pending": false,
  "response": {
    "phrase": "PENALTY MEAN FEDERAL SENSE AGREE SCALE EXHAUST ARROW HUB DAY VELVET AISLE LATIN NATURE CHEF GAUGE DARING REFUSE TINY REMIND MOMENT VINTAGE POLE ELEGANT",
    "seed": "0x64D1F2256C1C810A0AE273A397AC14C92335A234BFFBE259D9297CCF4F559F4B",
    "locked": false
  }
}
24 word seed phrase

It is essential to keep your 24 word seed phrase safe. You can recover your node with just those words. Anyone with access to your words can steal your coins!

  1. Write down the 24 word seed phrase and store it somewhere secure. You do not need to write down the 0x seed but you will need this in the next step.

  2. Wipe the private keys from the node by running the following command:

vault action:wipekeys seed:0x..

Example:

vault action:wipekeys seed:0x64D1F2256C1C810A0AE273A397AC14C92335A234BFFBE259D9297CCF4F559F4B
{
  "command": "vault",
  "params": {
    "action": "lock",
    "seed": "0x64D1F2256C1C810A0AE273A397AC14C92335A234BFFBE259D9297CCF4F559F4B"
  },
  "status": true,
  "pending": false,
  "response": "All private keys wiped!"
}

Your node no longer has the keys, not even encrypted in your UserDB. They are fully wiped.

You can only restore your keys with your 24 words using 

vault action:restorekeys phrase:"24 WORD SEED PHRASE HERE"
  1. Backup the wiped node. You will restore to your online node later.
    Optionally also set a password for the backup using A-Z, a-z and 0-9 characters only, no symbols
backup file:nokeysbackup.bak password:...
  1. Restore your private keys to the offline node
vault action:restorekeys phrase:"YOUR 24 WORDS HERE"
  1. Password lock your keys with a long, secure password - this will encrypt your private keys which can be decrypted for the purpose of signing transactions when required. This ensures you do not have to use the 24 words again, which can be kept somewhere safe and not touched again.
warning

The only time you should access your 24 words is if you lose your offline device! In this situation you can restore your wiped backup to a new offline device.

vault action:passwordlock password:setvaultpassword confirm:setvaultpassword

On Device 2 - The online node​

  1. Start a new node on an online device - your device 2

  2. Restore the wiped backup to this online node, entering the password from the backup if you set one:

restore file:nokeysbackup.bak password:...
  1. The node will shutdown, restart it to access your restored node.

This online node is now the same node as the one on the offline device, however it will be able to connect to the blockchain.

The online node can be used as normal to receive funds but cannot send any funds, it is essentially read only.

To send funds from your wallet, you will need to use both devices.

Transacting​

To make a transaction when using the Cold Storage solution, there are 5 steps. You will need to use the Terminal MiniDapp,Docker Terminal, or your desktop Command Line where Minima is running:

  1. On the online node, use the sendnosign command to create a transaction file, sending the amount you wish to send to your chosen recipient's address
  2. Transfer the unsigned transaction file to the offline device
  3. On the offline node, use the sendsign command to sign the transaction with your private keys
  4. Transfer the signed transaction file to the online device
  5. On the online device, use the sendpost command to post the signed transaction

Walk-through​

  1. On your online node, create a transaction using sendnosign.
tip

sendnosign works exactly like the traditional send function but instead of sending, will export an unsigned transaction (.txn) file which needs to be transferred to your offline device for signing with your private keys.

For additional help, use help command:sendnosign or help command:send.

Example output: (sending 1 Minima to the chosen address)

sendnosign amount:1 address:MxG0843TSJZ6U35CZSSR2D17G4TE9M68JVT4KUNR4TBQ6H9TRBFZYH23D50TRSH
{
  "command":"sendnosign",
  "params":{
    "amount":"1",
    "address":"MxG0843TSJZ6U35CZSSR2D17G4TE9M68JVT4KUNR4TBQ6H9TRBFZYH23D50TRSH"
  },
  "status":true,
  "pending":false,
  "response":{
    "txpow":"/home/minima/data/unsignedtransaction-1672851796504.txn"
  }
}

  1. Find the file in your Minima base folder and transfer the transaction file to your offline node via a USB key.

  2. To sign the transaction file, use sendsign inserting the name of the .txn file and your Vault password that you used in step 9 above to encrypt (passwordlock) your keys. This will decrypt your keys, sign the transaction and automatically re-encrypt them with the same password.

sendsign file:... password:yourvaultpassword

This will export a .txn file containing your signed transaction.

Example output:

sendsign file:/home/minima/data/unsignedtransaction-1672851796504.txn password:yourvaultpassword
{
  "command":"sendsign",
  "params":{
    "file":"/home/minima/data/unsignedtransaction-1672851796504.txn"
    "password":"yourvaultpassword"
  },
  "status":true,
  "pending":false,
  "response":{
    "txpow":"/home/minima/data/signedtransaction-1672852113421.txn"
  }
}

Alternatively, you can unlock your node first using:

vault action:passwordunlock password:yourvaultpassword

then use

sendsign file:...

then, re-lock your node

vault action:passwordlock password:yourvaultpassword confirm:yourvaultpassword

  1. Transfer the signed transaction file back to your online node using a USB key, ensuring it is in your node's basefolder.

  2. Broadcast the transaction to the Minima network with sendpost file: function.

Example output:

sendpost file:/home/minima/data/signedtransaction-1672852113421.txn
{
  "command":"sendpost",
  "params":{
    "file":"/home/minima/data/signedtransaction-1672852113421.txn"
  },
  "status":true,
  "pending":false,
  "response":{
    "txpow":{
      "txpowid":"0xB41C5F1D68E33410337D0A98EFF5C937F1B9189C46F0BB3F82271B017BFF07F3",
…

That's it. You can also view the signed or unsigned transaction at any time using sendview file:

Example output:

sendview file:/home/minima/data/signedtransaction-1672852113421.txn
{
  "command":"sendview",
  "params":{
    "file":"/home/minima/data/signedtransaction-1672852113421.txn"
  },
  "status":true,
  "pending":false,
  "response":{
    "txpow":{
      "txpowid":"0xB41C5F1D68E33410337D0A98EFF5C937F1B9189C46F0BB3F82271B017BFF07F3",
      "isblock":false,
      "istransaction":false,
      "superblock":-1…