{"id":6090,"date":"2026-09-16T07:00:00","date_gmt":"2026-09-16T04:00:00","guid":{"rendered":"https:\/\/www.dataplatform.gr\/?p=6090"},"modified":"2026-09-16T13:56:28","modified_gmt":"2026-09-16T10:56:28","slug":"pos-energopoioyme-to-data-masking-se-postgresql","status":"publish","type":"post","link":"https:\/\/www.dataplatform.gr\/en\/pos-energopoioyme-to-data-masking-se-postgresql\/","title":{"rendered":"How to enable Data Masking in PostgreSQL"},"content":{"rendered":"

In this article we will see how we can implement data anonymization and masking in a PostgreSQL 14 database using the extension PostgreSQL Anonymizer<\/strong>We will cover the installation process, setting up masking rules, as well as the specifics we encounter in this version regarding Transparent Dynamic Masking and the use of Views.<\/p>\n\n\n\n

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The installation<\/h2>\n\n\n\n

To install the extension on RHEL Unix, run the following:<\/p>\n\n\n\n

sudo yum install -y postgresql_anonymizer_14<\/pre>\n\n\n\n
In order for PostgreSQL to load the extension into its core, we need to declare it in the shared_preload_libraries<\/code> in the postgresql.conf<\/code>:<\/p>\n\n\n\n
su postgres\nvi $PGDATA\/postgresql.conf<\/pre>\n\n\n\n
Add or modify the line:<\/p>\n\n\n\n
shared_preload_libraries = 'anon'<\/code><\/pre>\n\n\n\n
Then, we restart the PostgreSQL service for the changes to take effect:<\/p>\n\n\n\n
sudo systemctl restart postgresql-14<\/pre>\n\n\n\n
Now we connect to our database and activate the extension:<\/p>\n\n\n\n
CREATE EXTENSION anon CASCADE;\n<\/pre>\n\n\n\n
(Optionally, if the architecture and version allow it, we enable transparent masking at the base level)<\/em>:<\/p>\n\n\n\n
ALTER DATABASE db_test SET anon.transparent_dynamic_masking TO true;\n<\/pre>\n\n\n\n
(Note: After this command you may need to re-enter sudo systemctl restart postgresql-14<\/code>)<\/em>.<\/p>\n\n\n\n
To check that it is activated, run the following:<\/p>\n\n\n\n
SELECT name, setting \nFROM pg_settings \nWHERE name = 'anon.transparent_dynamic_masking';<\/pre>\n\n\n\n
<\/p>\n\n\n\n
How do we define Masking rules?<\/h2>\n\n\n\n
We can define masking at the column level using SECURITY LABEL<\/code>For example, in the table customers<\/code> We apply masking to emails, countries and partial hiding to surnames:<\/p>\n\n\n\n
SECURITY LABEL FOR anon ON COLUMN public.customers.email \nIS 'MASKED WITH FUNCTION anon.fake_email()';\n\nSECURITY LABEL FOR anon ON COLUMN public.customers.country \nIS 'MASKED WITH FUNCTION anon.fake_country()';\n\nSECURITY LABEL FOR anon ON COLUMN public.customers.last_name \nIS 'MASKED WITH FUNCTION anon.partial(last_name, 1, $$***$$, 1)';<\/pre>\n\n\n\n
The function partial()<\/code> is extremely useful as it allows us to keep a certain number of characters visible at the beginning and end, filling the spaces in between with a symbol (such as ***<\/code>).<\/p>\n\n\n\n
Its syntax is:<\/p>\n\n\n\n