Verifying TDE is enabled
You can find out whether TDE is present on a server by querying the data_encryption_version column of the pg_control_init table.
A value of 0 means TDE isn't enabled. Any nonzero value reflects the version of TDE in use. Currently, when TDE is enabled, this value is 1.
select data_encryption_version from pg_control_init();
Output
data_encryption_version
-------------------------
1
(1 row)