Key Management

Ledger support

It is possible and advised to use a hardware wallet to manage your keys, Tezos’ client supports Ledger Nano devices provided that you have a Tezos app installed. The apps were developed by Obsidian Systems and they provide a comprehensive tutorial on how to install it.

Ledger Manager

The preferred way to set up your Ledger is to install Ledger Live. On Linux make sure you correctly set up your udev rules as explained here. Connect your ledger, unlock it and go the dashboard. In Ledger Live install Tezos Wallet from the applications list and open it on the device.

Tezos Wallet app

Now on the client we can import the keys (make sure the device is in the Tezos Wallet app):

./tezos-client list connected ledgers

You can follow the instructions to import the ledger private key and you can choose between the root or a derived address. We can confirm the addition by listing known addresses:

./tezos-client import secret key my_ledger ledger://tz1XXXXXXXXXX
./tezos-client list known addresses

Optional: we can check that our ledger signs correctly using the following command and confirming on the device:

tezos-client show ledger path ledger://tz1XXXXXXXXXX

The address can now be used as any other with the exception that during an operation the device will prompt you to confirm when it’s time to sign an operation.

Tezos Baking app

In Ledger Live (with Developer Mode enabled), there is also a Tezos Baking app which allows a delegate to sign non-interactively e.g. there is no need to manually sign every block or endorsement. The application however is restricted to sign exclusively blocks and endorsement operations; it is not possible to sign for example a transfer. Furthermore the application keeps track of the last level baked and allows only to bake for increasing levels. This prevents signing blocks at levels below the latest block signed.

If you have tried the app on some network and want to use it on another network you might need to reset this level with the command:

tezos-client setup ledger to bake for my_ledger

More details can be found on the Tezos Ledger app.

Signer

Another solution to decouple the node from the signing process is to use the remote signer. Among the signing scheme supported by the client, that we can list with tezos-client list signing schemes, there are unix, tcp, http and https. These schemes send signing requests over their respective communication channel towards the tezos-signer, which can run on a different machine that stores the secret key.

Signer requests

The tezos-signer handles signing requests with the following format:

<magic_byte><data>

In the case of blocks or consensus operations for example, this format is instantiated as follows:

<magic_byte><chain_id><block|consensus_operation>

Starting with Octez v12 (supporting the Ithaca protocol), consensus operations also include preendorsements. The magic byte distinguishes pre-Ithaca messages from (post-)Ithaca messages, as follows:

Message type

Magic byte

Legacy block

0x01

Legacy endorsement

0x02

Transfer

0x03

Authenticated signing request

0x04

Michelson data

0x05

Block

0x11

Pre-endorsement

0x12

Endorsement

0x13

The magic byte values to be used by the signer can be restricted using its option --magic-bytes, as explained in the signer’s manual.

Signer configuration

In our home server we can generate a new key pair (or import one from a Ledger) and launch a signer that signs operations using these keys. The new keys are store in $HOME/.tezos-signer in the same format as tezos-client. On our internet facing vps we can then import a key with the address of the signer.

home~$ tezos-signer gen keys alice
home~$ cat ~/.tezos-signer/public_key_hashs
[ { "name": "alice", "value": "tz1abc..." } ]
home~$ tezos-signer launch socket signer -a home

vps~$ tezos-client import secret key alice tcp://home:7732/tz1abc...
vps~$ tezos-client sign bytes 0x00 for alice

Every time the client on vps needs to sign an operation for alice, it sends a signature request to the remote signer on home.

However, with the above method, the address of the signer is hard-coded into the remote key value. Consequently, if we ever have to move the signer to another machine or access it using another protocol, we will have to change all the remote keys. A more flexible method is to only register a key as being remote, and separately supply the address of the signer uisng the -R option:

vps~$ tezos-client -R 'tcp://home:7732' import secret key alice remote:tz1abc...
vps~$ tezos-client -R 'tcp://home:7732' sign bytes 0x00 for alice

Alternatively, the address of the signer can be recorded in environment variables:

vps~$ export TEZOS_SIGNER_TCP_HOST=home
vps~$ export TEZOS_SIGNER_TCP_PORT=7732
vps~$ tezos-client import secret key alice remote:tz1abc...
vps~$ tezos-client sign bytes 0x00 for alice

All the above methods can be retargeted to the other signing schemes, for instance, http:

home~$ tezos-signer launch http signer -a home

vps~$ tezos-client import secret key alice http://home:7732/tz1abc...
vps~$ tezos-client sign bytes 0x00 for alice

vps~$ tezos-client -R 'http://home:7732' import secret key alice remote:tz1abc...
vps~$ tezos-client -R 'http://home:7732' sign bytes 0x00 for alice

vps~$ export TEZOS_SIGNER_HTTP_HOST=home
vps~$ export TEZOS_SIGNER_HTTP_PORT=7732
vps~$ tezos-client import secret key alice remote:tz1abc...
vps~$ tezos-client sign bytes 0x00 for alice

The complete list of environment variables for connecting to the remote signer is:

  • TEZOS_SIGNER_TCP_HOST

  • TEZOS_SIGNER_TCP_PORT (default: 7732)

  • TEZOS_SIGNER_HTTP_HOST

  • TEZOS_SIGNER_HTTP_PORT (default: 6732)

  • TEZOS_SIGNER_HTTPS_HOST

  • TEZOS_SIGNER_HTTPS_PORT (default: 443)

  • TEZOS_SIGNER_UNIX_PATH

  • TEZOS_SIGNER_HTTP_HEADERS

Secure the connection

Note that this setup alone is not secure, the signer accepts requests from anybody and happily signs any transaction!

Improving the security of the communication channel can be done at the system level, setting up a tunnel with ssh or wireguard between home and vps, otherwise the signer already provides an additional protection.

With the option --require-authentication the signer requires the client to authenticate before signing any operation. First we create a new key on the vps and then import it as an authorized key on home where it is stored under .tezos-signer/authorized_keys (similarly to ssh). Note that this key is only used to authenticate the client to the signer and it is not used as a Tezos account.

vps~$ tezos-client gen keys vps
vps~$ cat ~/.tezos-client/public_keys
[ { "name": "vps",
    "value":
       "unencrypted:edpk123456789" } ]

home~$ tezos-signer add authorized key edpk123456789 --name vps
home~$ tezos-signer --require-authentication launch socket signer -a home-ip

All request are now signed with the vps key thus you are guaranteed authenticity and integrity. This set up does not guarantee confidentiality, an eavesdropper can see the transactions that you sign but on a public blockchain this is less of a concern. You can still use the https scheme or the tunnel to encrypt your traffic.

Activate fundraiser account - Mainnet

If you took part in the fundraiser you can activate your account for the Mainnet on https://check.tezos.com/. This feature is also included in some wallets. If you have any questions or issues, refer to that page or to the Tezos foundation for support.

You may also use tezos-client to activate your account, be warned that you should have a very good understanding of key management in Tezos and be familiar with the command-line. The first step is to recover your private key using the following command which will ask for:

  • the email address used during the fundraiser

  • the 14 words mnemonic of your paper wallet

  • the password used to protect the paper wallet

tezos-client import fundraiser key alice

Once you insert all the required information, the client computes your secret key and it asks to create a new password to store your secret key on disk encrypted.

If you haven’t already activated your account on the website, you can use this command with the activation code obtained from the Tezos foundation.

tezos-client activate fundraiser account alice with <code>

Like explained above, your keys are stored under ~/.tezos-client. We strongly advice you to first make a backup and then transfer your tokens to a new pair of keys imported from a ledger (see Ledger support).

Check the balance with:

tezos-client get balance for alice