# Setting up the keyring
This document describes how to configure and use the keyring and its various backends for an application.
The keyring holds the private/public keypairs used to interact with a node. For instance, a validator key needs to be set up before running the blockchain node, so that blocks can be correctly signed. The private key can be stored in different locations, called "backends", such as a file or the operating system's own key storage.
# Available backends for the keyring
Starting with the v0.38.0 release, Cosmos SDK comes with a new keyring implementation that provides a set of commands to manage cryptographic keys in a secure fashion. The new keyring supports multiple storage backends, some of which may not be available on all operating systems.
# The os backend
The os backend relies on operating system-specific defaults to handle key storage
securely. Typically, an operating system's credential sub-system handles password prompts,
private keys storage, and user sessions according to the user's password policies. Here
is a list of the most popular operating systems and their respective passwords manager:
- macOS (since Mac OS 8.6): Keychain (opens new window)
- Windows: Credentials Management API (opens new window)
- GNU/Linux:
GNU/Linux distributions that use GNOME as default desktop environment typically come with
Seahorse (opens new window). Users of KDE based distributions are
commonly provided with KDE Wallet Manager (opens new window).
Whilst the former is in fact a libsecret convenient frontend, the latter is a kwallet
client.
os is the default option since operating system's default credentials managers are
designed to meet users' most common needs and provide them with a comfortable
experience without compromising on security.
The recommended backends for headless environments are file and pass.
# The file backend
The file backend more closely resembles the keybase implementation used prior to
v0.38.1. It stores the keyring encrypted within the app's configuration directory. This
keyring will request a password each time it is accessed, which may occur multiple
times in a single command resulting in repeated password prompts. If using bash scripts
to execute commands using the file option you may want to utilize the following format
for multiple prompts:
The first time you add a key to an empty keyring, you will be prompted to type the password twice.
# The pass backend
The pass backend uses the pass (opens new window) utility to manage on-disk
encryption of keys' sensitive data and metadata. Keys are stored inside gpg encrypted files
within app-specific directories. pass is available for the most popular UNIX
operating systems as well as GNU/Linux distributions. Please refer to its manual page for
information on how to download and install it.
pass uses GnuPG (opens new window) for encryption. gpg automatically invokes the gpg-agent
daemon upon execution, which handles the caching of GnuPG credentials. Please refer to gpg-agent
man page for more information on how to configure cache parameters such as credentials TTL and
passphrase expiration.
The password store must be set up prior to first use:
Replace <GPG_KEY_ID> with your GPG key ID. You can use your personal GPG key or an alternative
one you may want to use specifically to encrypt the password store.
# The kwallet backend
The kwallet backend uses KDE Wallet Manager, which comes installed by default on the
GNU/Linux distributions that ships KDE as default desktop environment. Please refer to
KWallet Handbook (opens new window) for more
information.
# The test backend
The test backend is a password-less variation of the file backend. Keys are stored
unencrypted on disk.
Provided for testing purposes only. The test backend is not recommended for use in production environments.
# The memory backend
The memory backend stores keys in memory. The keys are immediately deleted after the program has exited.
Provided for testing purposes only. The memory backend is not recommended for use in production environments.
# Adding keys to the keyring
Make sure you can build your own binary, and replace simd with the name of your binary in the snippets.
Applications developed using the Cosmos SDK come with the keys subcommand. For the purpose of this tutorial, we're running the simd CLI, which is an application built using the Cosmos SDK for testing and educational purposes. For more information, see simapp (opens new window).
You can use simd keys for help about the keys command and simd keys [command] --help for more information about a particular subcommand.
You can also enable auto-completion with the simd completion command. For example, at the start of a bash session, run . <(simd completion), and all simd subcommands will be auto-completed.
To create a new key in the keyring, run the add subcommand with a <key_name> argument. For the purpose of this tutorial, we will solely use the test backend, and call our new key my_validator. This key will be used in the next section.
This command generates a new 24-word mnemonic phrase, persists it to the relevant backend, and outputs information about the keypair. If this keypair will be used to hold value-bearing tokens, be sure to write down the mnemonic phrase somewhere safe!
By default, the keyring generates a secp256k1 keypair. The keyring also supports ed25519 keys, which may be created by passing the --algo ed25519 flag. A keyring can of course hold both types of keys simultaneously, and the Cosmos SDK's x/auth module (in particular its middlewares) supports natively these two public key algorithms.
# Next
Read about running a node