Configure KMIP encryption

Set up encryption using keys from a Key Management Interoperability Protocol (KMIP) host to protect sensitive configuration file properties, system resources, and tables.

DataStax recommends using KMIP key server security policies to limit the number of nodes in the cluster that can remotely manage keys, due to the risks associated with expiring, revoking, and destroying keys.

Add a KMIP Host

Hyper-Converged Database (HCD) supports using encryption keys from one or more remote Key Management Interoperability Protocol (KMIP) hosts to encrypt or decrypt table data or sensitive properties, or both, in the hcd.yaml and cassandra.yaml configuration files.

The location of each configuration file depends on the type of installation:

Configuration file location
Filename Package installations Tarball installations

cassandra.yaml

/etc/hcd/cassandra/cassandra.yaml

<installation_location>/resources/cassandra/conf/cassandra.yaml

hcd.yaml

/etc/hcd/hcd.yaml

<installation_location>/resources/hcd/conf/hcd.yaml

Follow these steps to add a KMIP server information to the list of available hosts.

DataStax recommends limiting the number of nodes that can remotely manage KMIP keys using a security policy on the KMIP host.

Set up a KMIP host

Perform all steps on every node in the cluster.

  1. Set up KMIP agents and registered DSE with the KMIP service:

    Refer to the KMIP key provider documentation for detailed steps.

    1. Download and install the KMIP agent.

    2. Connect to the KMIP host.

    3. Register the HCD node.

    4. Locate the SSL key pair generated by the KMIP agent.

  2. Convert the key pair from PEM to an HCD compatible JKS format:

    1. Secure the KMIP agent private key files by removing read access for all users. For example, the Vormetric DSM agents creates two files named kmip-key.pem and kmip-<host_name>.pem.

    2. Copy both keys to another directory, such as your home directory.

    3. Generate a PKCS12 format file from the PEM files:

      openssl pkcs12 -export -out <kmip_keystore>.p12 -inkey <kmip-key.pem> -in <kmip-host_name.pem>

      Where <kmip_keystore>.p12 is the output file name and <kmip-host_name.pem> is part of the key pair created by the KMIP agent.

Due to an OpenSSL issue, you cannot use a PKCS12 truststore that was generated via OpenSSL. For example, a truststore generated via the following command will not work with DSE:

openssl pkcs12 -export -nokeys -out truststore.pfx -in <intermediate.chain.pem>

However, truststores generated via Java’s keytool and then converted to PKCS12 work with DSE. Example:

keytool -importcert -alias <rootca> -file <rootca.pem> -keystore <truststore.jks>
keytool -importcert -alias <intermediate> -file <intermediate.pem> -keystore <truststore.jks>
keytool -importkeystore -srckeystore <truststore.jks> -destkeystore <truststore.pfx> -deststoretype pkcs12

  1. Create a JKS keystore:

    keytool -importkeystore -destkeystore <kmip_keystore.jks> -srcstoretype PKCS12 -srckeystore <kmip_keystore.p12>

    Where

    • <kmip_keystore.jks> is the keystore file name that is created

    • <kmip_keystore.p12> is the PKC12 file generated in the previous step

      Enter a password for the keystore at the prompt and fill out the host information.

  2. Install the KMIP root certificate into the JKS truststore:

    keytool -import -alias <kmipCA> -file <kmip-host_CA.pem> -keystore <kmip_truststore.jks>

    Enter a password for the truststore at the prompt and fill out the host information.

  3. Move the keystore and truststore to a directory accessible by HCD and change the file to allow the HCD account read/write access.

  4. Delete or secure the files used to create the keystore and truststore.

    1. Add the host details to the kmip_hosts section of the hcd.yaml:

      kmip_hosts:
  <kmip_group_name>:
    hosts: <FQDN>[, <FQDN> , ...]
    keystore_path: </etc/hcd/conf/kmip_keystore.jks>
    keystore_type: jks
    keystore_password: <password>
    truststore_path: </etc/hcd/conf/kmip_truststore.jks>
    truststore_type: jks
    truststore_password: <password>
    key_cache_millis: <N>
    timeout: <N>
    protocol: <protocol>
    cipher_suites: <supported_cipher>

      • Required settings:

        • <kmip_group_name>: User-defined group name that identifies the KMIP host in HCD related commands.

        • hosts: Comma separated list of Fully-Qualified Domain Names (FQDN) of KMIP hosts. HCD tries the hosts in the order listed.

        • keystore_path: Location of the keystore created in 2.

        • keystore_type: jks Keystore format. Must be set to jks.

        • keystore_password: Password of the keystore file created in 2.

        • truststore_path: Location of the truststore file created in 2.

        • truststore_type: jks Truststore format. Must be set to jks.

        • truststore_password: Password of the truststore file created in 2.

      • Optional settings:

        • key_cache_millis: <N> where N is the interval at which HCD refreshes the key cache on the node in milliseconds. The default is 300000 (five minutes).

        • timeout: <N> where N is the socket timeout in milliseconds. The default is 1000.

        • protocol: <protocol> for communicating between the node and KMIP key server. When not specified, JVM default is used.

        • cipher_suites: supported_cipher for communicating between the node and KMIP key server. When not specified, JVM default is used.

    2. Verify that the node can connect to the KMIP host by testing the connection:

      HCD does not include a built-in tool for listing KMIP keys directly. You must use your KMIP server’s native management interface or API to verify the connection and list keys.

      • Using your KMIP server’s management interface or API, verify the connection and list available keys.

      • Using your KMIP server’s command-line tools (if available):

        # Example using a generic KMIP client (actual command depends on your KMIP server)
kmip-client list-keys --server <kmip_server_host> --port <kmip_port>

        HCD picks up hcd.yaml changes without requiring a restart.

        If problems connecting to the KMIP server occur, see Troubleshoot KMIP connections.

    3. Repeat these steps on all nodes in the cluster.

Encrypt KMIP system resources

Use a KMIP key to encrypt the system.batchlog and system.paxos tables, hint files and commit logs.

Prerequisites

Complete the steps in Adding a KMIP host.

If any of the defined KMIP groups are not available, HCD startup fails.

Procedure

  1. Locate the hcd.yaml configuration file. The location of this file depends on the type of installation:

    • Package installations: /etc/hcd/hcd.yaml

    • Tarball installations: <installation_location>/resources/hcd/conf/hcd.yaml

  2. In the hcd.yaml file, configure encryption settings for system tables, the commit log, and the hints files.

    system_info_encryption:
  enabled: ( true | false )
  cipher_algorithm: <cipher_name>
  secret_key_strength: <length>
  key_provider: KmipKeyProviderFactory
  kmip_host: <kmip_group_name>
  chunk_length_kb: 64

    • Required properties:

      • enabled: Set to true. On the next startup, system resources are encrypted. If the system tables have existing data, use nodetool upgradesstables to apply encryption.

      • key_provider: Set to KmipKeyProviderFactory.

      • kmip_host: Use the group name from the kmip_hosts section.

    • Optional: To ensure that KMIP generates a compatible key, configure the type of encryption key to use:

      • cipher_algorithm: Set the name of a supported JCE cipher algorithm to use. HCD supports the following algorithms:

        Supported cipher algorithm names
        cipher_algorithm secret_key_strength

        AES

        128, 192, or 256

        DES

        56

        DESede

        112 or 168

        Blowfish

        32-448

        RC2

        40-128

      • secret_key_strength: Specify the key length.

      • chunk_length_kb: Configures chuck size for SSTables. The default 64 is used if the option is excluded. When these properties are set, HCD only uses a key that matches; if no matching key exists, start up fails.

  3. Perform a rolling restart.

  4. To encrypt existing data, run nodetool upgradesstables -a system batchlog paxos on all nodes in the cluster.

Encrypt table data with KMIP keys

Encrypt data stored in a table using a Key Management Interoperability Protocol (KMIP) key.

Prerequisites

Complete the steps in Adding a KMIP host.

If any of the defined KMIP groups are not available, HCD startup fails.

Use the hcd.yaml file to encrypt table data

  1. Locate the hcd.yaml configuration file. The location of this file depends on the type of installation:

    • Package installations: /etc/hcd/hcd.yaml

    • Tarball installations: <installation_location>/resources/hcd/conf/hcd.yaml

  2. To create a new encrypted table using a key from a KMIP server:

    • Encryption without compression:

      CREATE TABLE customers
  ...
  WITH COMPRESSION =
  { 'class': 'Encryptor',
  'key_provider': 'KmipKeyProviderFactory',
  'kmip_host': 'kmip_group_name'
    ['key_keyspace': 'kmip_keyspace'],
  'cipher_algorithm': 'AES/ECB/PKCS5Padding',
  'secret_key_strength': 128 };

      • 'key_provider': 'KmipKeyProviderFactory' tells the encryptor to use a KMIP key server to manage its encryption keys. Include the 'key provider' entry only to specify to use a KMIP key server, otherwise omit this entry.

      • 'kmip_host': 'kmip_group_name' ['key_keyspace': 'kmip_keyspace'] specify an optional KMIP keyspace. Use keyspaces to allow granular management of keys on a per table or keyspace basis.

    • Compression and encryption:

      CREATE TABLE customers
  ...
  WITH COMPRESSION =
  { 'class': 'EncryptingDeflateCompressor',
  'key_provider': 'KmipKeyProviderFactory',
  'kmip_host': 'kmip_group_name',
  'cipher_algorithm': 'AES/ECB/PKCS5Padding',
  'secret_key_strength': 128 };

  3. To encrypt a pre-existing table:

    1. Change the table compression settings:

      • Encryption without compression:

        ALTER TABLE customers
  ...
  WITH COMPRESSION =
  { 'class': 'Encryptor',
  'key_provider': 'KmipKeyProviderFactory',
  'kmip_host': 'kmip_group_name'
    ['key_keyspace': 'kmip_keyspace'],
  'cipher_algorithm': 'AES/ECB/PKCS5Padding',
  'secret_key_strength': 128 };

        • 'key_provider': 'KmipKeyProviderFactory' tells the encryptor to use a KMIP key server to manage its encryption keys. Include the 'key provider' entry only to specify to use a KMIP key server, otherwise omit this entry.

        • ['key_keyspace': 'kmip_keyspace'] specify an optional KMIP keyspace. Use keyspaces to allow granular management of keys on a per table or keyspace basis.

      • Compression and encryption:

        ALTER TABLE customers
  ...
  WITH COMPRESSION =
  { 'class': 'EncryptingDeflateCompressor',
  'key_provider': 'KmipKeyProviderFactory',
  'kmip_host': 'kmip_group_name',
  'cipher_algorithm': 'AES/ECB/PKCS5Padding',
  'secret_key_strength': 128 };

    2. Encrypt existing data on all nodes in the cluster:

    nodetool upgradesstables -a [keyspace_name [table_name[ tablename]...]

Rekey tables using a new key

Change the encryption key that is used for both encrypting new data and decrypting the existing data. Use these steps to secure the data after an event that potentially compromised an encryption key, such as a change in security administration staff. Before destroying the old key, revoke the compromised KMIP key, wait for the database key cache refresh, and then re-encrypt existing SSTables with the new key.

The database caches the encryption keys and refreshes the cache at an interval set by the key_cache_millis (default setting is 5 minutes). To get a new key, either wait for the key cache refresh interval or perform a rolling restart.

HCD supports KMIP key management through direct KMIP server interaction. The KMIP commands affect encryption keys as follows:

  • expirekey: Database stops using the key for encryption at the specified time and continues to use the expired key to decrypt existing data. Data re-keying is not required.

    Use this command to satisfy security policies that require periodic switching of the encryption key.

  • revoke: Permanently disables the key on the KMIP server. Database can no longer use the key for encryption, but continues to use the key for decryption of existing data. Re-encrypt existing data before completely removing the key from the KMIP server.

    Use this command as the first step when replacing a compromised key.

  • destroy: Completely removes the key from the KMIP server. Database can no longer use the key for encryption or decryption. Existing data that has not been re-encrypted becomes inaccessible.

    Use this command only after revoking a key and re-encrypting existing data.

Prerequisites

  1. Back up SSTables.

Procedure

  1. Revoke the compromised key.

You must manage KMIP keys directly through your KMIP server’s interface or API.

  1. Get the ID of the KMIP encryption key you want to revoke from the KMIP server:

    • Using your KMIP server’s management interface or API, list the available keys and their states.

    • Using your KMIP server’s command-line tools (if available):

      # Example using a generic KMIP client (actual command depends on your KMIP server)
kmip-client list-keys --server <kmip_server_host> --port <kmip_port>

      The following is an example of a KMIP server that has two keys, active and deactivated:

      ID                                     Name          Cipher         State                Activation Date   Creation Date              Protect Stop Date   Keyspace
02-449   82413ef3-4fa6-4d4d-9dc8-71370d731fe4_0   AES/CBC/PKCS5   Deactivated   Mon Apr 25 20:25:47 UTC 2016             n/a                            n/a         n/a
02-540   0eb2277e-0acc-4adb-9241-1dd84dde691c_0             AES        Active   Tue May 31 12:57:59 UTC 2016             n/a                            n/a         n/a

      HCD supports one or more KMIP hosts. Each KMIP host is defined under a user-defined <kmip_group_name> in the kmip_hosts section of the hcd.yaml configuration file.

      The location of the hcd.yaml file depends on the type of installation:

      • Package installations: /etc/hcd/hcd.yaml

      • Tarball installations: <installation_location>/resources/hcd/conf/hcd.yaml

  2. Revoke the key you want to replace using the ID:

    • Using your KMIP server’s management interface or API, revoke the key with the specified ID.

    • Using your KMIP server’s command-line tools (if available):

      # Example using a generic KMIP client (actual command depends on your KMIP server)
kmip-client revoke-key --server <kmip_server_host> --port <kmip_port> --key-id <key_id>

      Revoking permanently deactivates the key on the KMIP server. When the key cache refreshes, a new key for encryption or decryption is automatically created. Revoked keys are used to decrypt existing data. DO NOT destroy the revoked key until after re-encrypting the existing data.

  3. Verify that the key State is Deactivated:

    • Using your KMIP server’s management interface or API, verify the key state has changed to Deactivated.

    • Using your KMIP server’s command-line tools (if available):

      # Example using a generic KMIP client (actual command depends on your KMIP server)
kmip-client list-keys --server <kmip_server_host> --port <kmip_port>

      The following is an example of a KMIP server that has two keys:

      ID                                     Name               Cipher         State                Activation Date   Creation Date              Protect Stop Date   Keyspace
02-449   82413ef3-4fa6-4d4d-9dc8-71370d731fe4_0        AES/CBC/PKCS5   Deactivated   Mon Apr 25 20:25:47 UTC 2016             n/a                            n/a         n/a
02-540   0eb2277e-0acc-4adb-9241-1dd84dde691c_0                  AES   Deactivated   Tue May 31 12:57:59 UTC 2016             n/a   Thu Jul 27 17:16:38 UTC 2017

      1. Refresh the database key cache using one of the following methods:

    • Wait the amount of time specified in the key_cache_millis setting before continuing to the next step.

    • Perform a rolling restart.

      KMIP keys are cached on the HCD node. HCD refreshes the cache and a new key is automatically generated by the KMIP server after key_cache_millis lapses; the default setting is 5 minutes.

      1. Optional: Get a list of the affected tables to re-encrypt using the new key using the DESC keyspace command:

        For example to find all tables in the cycling keyspace that use the KMIP group:

        DESC KEYSPACE cycling

      2. Use nodetool upgradesstables to rewrite the encrypted SSTables using the new key. Run the following command on every node in the cluster:

    • Target only specific tables:

      nodetool upgradesstables --include-all-sstables keyspace_name table_name [table_name …]

    • Target specific keyspace:

      nodetool upgradesstables --include-all-sstables keyspace_name

    • All keyspaces and tables:

      nodetool upgradesstables --include-all-sstables

      1. Optional: Remove the encryption key so that it is no longer available for decryption:

    • Using your KMIP server’s management interface or API, destroy the key with the specified ID.

    • Using your KMIP server’s command-line tools (if available):

      # Example using a generic KMIP client (actual command depends on your KMIP server)
kmip-client destroy-key --server <kmip_server_host> --port <kmip_port> --key-id <key_id>

      The backed up SSTables are only accessible using the old key. Ensure that the data is accessible before removing the key.

Troubleshoot KMIP connections

The following error message may occur if the HCD SSL certificate is self-signed or from a CA that has not been added to the certificate chain on the KMIP server.

WARN 14:46:42,928 Unable to connect to KMIP host: 10.120.15.100:9005
com.cryptsoft.kmip.TTLVReadException: Error reading TTLV ResponseMessage. Got end-of-stream after reading 0 byte(s). Read bytes: (0) []

Ensure that trust between HCD and KMIP host has been properly configured, see Creating local SSL certificate and keystore files.

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