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Keys Config

Tessera uses cryptographic keys to provide transaction privacy.

You can use existing private/public key pairs as well as use Tessera to generate new key pairs for you. See Generating & securing keys for more info.

"keys": {
    "passwords": [],
    "passwordFile": "Path",
    "azureKeyVaultConfig": {
        "url": "Url"
    },
    "hashicorpKeyVaultConfig": {
        "url": "Url",
        "approlePath": "String",
        "tlsKeyStorePath": "Path",
        "tlsTrustStorePath": "Path" 
    },
    "keyData": [
        {
            //The data for a private/public key pair
        }
    ]
}

KeyData

Key pairs can be provided in several ways:

1. Direct key pairs

Direct key pairs are convenient but are the least secure configuration option available, as you expose your private key in the configuration file. More secure options are available and preferable for production environments.

The key pair data is provided in plain text in the configfile:

"keys": {
    "keyData": [
        {
        "privateKey": "yAWAJjwPqUtNVlqGjSrBmr1/iIkghuOh1803Yzx9jLM=",
        "publicKey": "/+UuD63zItL1EbjxkKUljMgG8Z1w0AJ8pNOR4iq2yQc="
        }
    ]
}

2. Inline key pairs

The public key is provided in plain text. The private key is provided through additional config:

"keys": {
    "keyData": [
        {
            "config": {
                "data": {
                    "bytes": "yAWAJjwPqUtNVlqGjSrBmr1/iIkghuOh1803Yzx9jLM="
                },
                "type": "unlocked"
            },
            "publicKey": "/+UuD63zItL1EbjxkKUljMgG8Z1w0AJ8pNOR4iq2yQc="
        }
    ]
}     

This allows for the use of Argon2 password-secured private keys by including the corresponding Argon2 settings in the additional config:

"keys": {
    "passwords": ["password"],
    "keyData": [
        {
            "config": {
                "data": {
                    "aopts": {
                        "variant": "id",
                        "memory": 1048576,
                        "iterations": 10,
                        "parallelism": 4,
                    },
                    "snonce": "x3HUNXH6LQldKtEv3q0h0hR4S12Ur9pC",
                    "asalt": "7Sem2tc6fjEfW3yYUDN/kSslKEW0e1zqKnBCWbZu2Zw=",
                    "sbox": "d0CmRus0rP0bdc7P7d/wnOyEW14pwFJmcLbdu2W3HmDNRWVJtoNpHrauA/Sr5Vxc"
                },
                "type": "argon2sbox"
            },
            "publicKey": "/+UuD63zItL1EbjxkKUljMgG8Z1w0AJ8pNOR4iq2yQc="
        }
    ]
}

3. Azure Key Vault key pairs

The keys in the pair are stored as secrets in an Azure Key Vault. This requires providing the vault url and the secret IDs for both keys:

"keys": {
    "azureKeyVaultConfig": {
        "url": "https://my-vault.vault.azure.net"
    },
    "keyData": [
        {
            "azureVaultPrivateKeyId": "Key",
            "azureVaultPublicKeyId": "Pub",
            "azureVaultPublicKeyVersion": "bvfw05z4cbu11ra2g94e43v9xxewqdq7",
            "azureVaultPrivateKeyVersion": "0my1ora2dciijx5jq9gv07sauzs5wjo2"
        }
    ]
}

This example configuration will retrieve the specified versions of the secrets Key and Pub from the key vault with DNS name https://my-vault.vault.azure.net. If no version is specified then the latest version of the secret is retrieved.

Environment variables must be set if using an Azure Key Vault, for more information see Setting up an Azure Key Vault

4. Hashicorp Vault key pairs

The keys in the pair are stored as a secret in a Hashicorp Vault. Additional configuration can also be provided if the Vault is configured to use TLS and if the AppRole auth method is being used at a different path to the default (approle):

"hashicorpKeyVaultConfig": {
    "url": "https://localhost:8200",
    "tlsKeyStorePath": "/path/to/keystore.jks",
    "tlsTrustStorePath": "/path/to/truststore.jks",
    "approlePath": "not-default",
},
"keyData": [
    {
        "hashicorpVaultSecretEngineName": "engine",
        "hashicorpVaultSecretName": "secret",
        "hashicorpVaultSecretVersion": 1,
        "hashicorpVaultPrivateKeyId": "privateKey",
        "hashicorpVaultPublicKeyId": "publicKey",
    }
]

This example configuration will retrieve version 1 of the secret engine/secret from Vault and its corresponding values for privateKey and publicKey.

If no hashicorpVaultSecretVersion is provided then the latest version for the secret will be retrieved by default.

Tessera requires TLS certificates and keys to be stored in .jks Java keystore format. If the .jks files are password protected then the following environment variables must be set: * HASHICORP_CLIENT_KEYSTORE_PWD * HASHICORP_CLIENT_TRUSTSTORE_PWD

If using a Hashicorp Vault additional environment variables must be set and a version 2 K/V secret engine must be enabled. For more information see Setting up a Hashicorp Vault.

5. Filesystem key pairs

The keys in the pair are stored in files:

"keys": {
    "passwordFile": "/path/to/passwords",
    "keyData": [
        {
            "privateKeyPath": "/path/to/privateKey.key",
            "publicKeyPath": "/path/to/publicKey.pub"
        }
    ]
}

The contents of the public key file must contain the public key only, e.g.:

/+UuD63zItL1EbjxkKUljMgG8Z1w0AJ8pNOR4iq2yQc=

The contents of the private key file must contain the private key in the config format, e.g.:

{
    "type" : "unlocked",
    "data" : {
        "bytes" : "DK0HDgMWJKtZVaP31mPhk6TJNACfVzz7VZv2PsQZeKM="
    }
}

Multiple Keys

If wished, multiple key pairs can be specified for a Tessera node. In this case, any one of the public keys can be used to address a private transaction to that node. Tessera will sequentially try each key to find one that can decrypt the payload. This can be used, for example, to simplify key rotation.

Note that multiple key pairs can only be set up within the configuration file, not via separate filesystem key files.

Viewing the keys registered for a node

An ADMIN API endpoint /config/keypairs exists to allow you to view the public keys of the key pairs currently in use by your Tessera node. This requires configuring an ADMIN server in the node’s configuration file, as described in Configuration Overview.

A sample response for the request adminhost:port/config/keypairs is:

[
   {
      "publicKey" : "oNspPPgszVUFw0qmGFfWwh1uxVUXgvBxleXORHj07g8="
   },
   {
      "publicKey" : "ABn6zhBth2qpdrJXp98IvjExV212ALl3j4U//nj4FAI="
   }
]