This article describes the concept of chained signature for object history in Smart ID Identity Manager.
To allow deletion of older entries, the verification of object history can be limited to a window of the previous N months, with N being >= 12. Smaller values will be overridden by 12.
In the object history, all changes on each object (employees, cards, certificates, requests etc.) are tracked. This can, for example, be that data is changed, status (like deactivate card) is changed, or if a process is executed (start Smart ID Mobile App provisioning) etc. This history is signed, so that it is recognized if someone modifies the records in the database. Chained signature means that each entry of the object history is signed. The signature is based on the signature of the previous entry, so it is not possible to add, remove or change an entry without breaking the chain. Thus every manipulation of the object history can be detected as long as the head of the chain is protected. The chained signature spans over all history entries, regardless of tenant.
- The certificates used for signing and verification need to be valid for digital signatures. Otherwise Identity Manager will fail on writing to the database.
- The parameter
commonHistoryService.verificationIntervalMonthsin the system properties part of the docker-compose.yml file for Identity Manager Operator was renamed to
commonHistoryService.historyCutOffDurationin Smart ID 22.04. Make sure you rename it accordingly in your configuration. See also List of Identity Manager system properties.
- Add/update the following section and configure it as desired (explained further down in this document).
The default CRON expression for the history cleaning task has been added to be executed on Fridays only. This is a new property added for the history cleaning task:
Furthermore, the default CRON expression for the history verification task has changed, so it executes only on Sundays, not daily:
Configure chained signature
The keys and certificates used for signing and verification are configured in the encrypt and sign engine's configuration, typically found under engineSignEncryptConfig.xml.
Configure the key used for the chained signature via the property
descriptorNameof the bean
historyServiceSigner. Add the following in the system properties part of the docker-compose.yml file:
If the chained signature is not configured, Tomcat startup will fail with an error message like:
Verify chained signature
Verification consists of traversing over all entries of the object history, regardless of tenant, and verifying its signature.
Verify the chained signatures with a REST service call to this url:
where the tenantId is optional.
The login can be done via basic authentication. For example, if you log in as admin/admin the following header is added, where
YWRtaW46YWRtaW4=is the "admin:admin" Base64-encoded:
- Some REST service clients support convenient entry of basic authentication with fields. If preemptive authentication is offered, you should use that, since the REST service do not ask for authentication, but rather just fail if no authentication is offered.
- The result is either 'true' if everything is fine or 'false' if a verification failed. Details about verification errors are listed in a log file.
A successful verification is only possible if at least one entry is already signed.
A scheduled job regularly checks the signature chain of the object history. If an error is found, it will send an email to configurable recipients.
As the object history signature spans over all history entries, regardless of the tenant, the verification on a multi tenant system should be done by a dedicated user that belongs to no tenant (that is, it has a null tenantId), but who performs this task for the whole system. Use the Identity Manager Tenant application to create such a user:
In the system properties part of the docker-compose.yml file, set the following (also needed for "scheduled cleaning" below):
- Configure the SMTP server in Identity Manager. See Set up email template in Identity Manager.
Several attributes can be configured in the system properties part of the docker-compose.yml file. Note that a property may span over several lines by ending intermediate lines with a backslash. At the very least, you must configure a recipient.
This is an example:
- Also see "Define Cut-Off For Verification / Cleanup Window" below!
Delete old history entries
The periodically running
HistoryCleaningJob deletes history entries that are no longer needed for verification in the current verification window, as defined by the configured cut-off (see below).
A scheduled job regularly cleans the signature chain of the object history.
As the object history signature spans over all history entries, regardless of the tenant, the cleaning on a multi tenant system should be done by a dedicated user that belongs to no tenant (that is, it has a null tenantId), but who performs this task for the whole system. Use the Identity Manager Tenant application to create such a user:
In the docker-compose.yml file, set the following system property: (also needed "scheduled verification" above):
Several attributes can be configured with system properties. Note that a property may span over several lines by ending intermediate lines with a backslash.
This is an example of a configuration of the system property:
- Also see "Define Cut-Off For Verification / Cleanup Window" below.
To be able to delete history entries when deleting a core object, you must add the
objectHistoryRemovalStrategy.removeWhenDeletingCoreObject property to the system properties part of the docker-compose.yml file for Identity Manager Operator. This property is intentionally not provided by default.
If you delete any history entries, the signature chain will be broken. This is not reversible.
In the system properties part of the docker-compose.yml file, add the property below and set it to true:
Now the history entries will be deleted together with the core object itself.
This feature only works for datapools with internal data sources, that is, internal table and lookup table.
Define cut-off for verification/cleanup window
By default the verification windows spans the entire history. You can limit it to the last N >= 12 months. This will enable deletion of older entries outside the verification window. Smaller values will be overridden by 12.
This will enable cleanup of older entries outside the verification window to reduce the amount of stored data.
The cleanup process is irreversible, so be careful on how you configure the verification window before you run the deletion job for the first time!
If no cut-off is specified, the entire history is validated (default), and cleanup has no effect.
In the system properties part of the docker-compose.yml file, enter this to specify a window starting 12 months in the past and ending at the current time:
Note that if a verification window is set, the following applies:
- verification will fail if the oldest entry of any chain within the verification window points to a deleted predecessor
- if verification fails for entries outside the verification window, this will be logged
In a clustered environment there is a separate chain per cluster node. With the default configuration, the chain's name is derived from the cluster node, that is, the
jvmRoute attribute of the engine tag found in the server.xml. The implementation uses only the primary engine and does not support any special cases.
If there is a special cluster configuration, or if a cluster is not based on a unique
jvmRoute per node, the attribute
commonHistoryService.chainName needs to be provided. If this attribute is not found, like typically in single node environments,
PRIME1 is used as default name.
Each history entry corresponds to an action that was performed on a core object in Identity Manager. Thus it belongs to a single tenant. The chained signature of the history on the other hand is global: there's exactly one chain for each cluster node, that spans over all history entries, regardless of the tenant. The signature ensures that no history entry of a Identity Manager cluster node has been manipulated.
For this reason it is recommended that the signature verification is performed by an administrator that is not bound to a tenant, that is, with an tenantId of null. The scheduled task that performs history verification should, in case of an error, be configured to send an email to a global user that administers Identity Manager for all tenants. It is still possible to verify the signatures with a user belonging to a tenant, but this should only be done on single tenant systems.