How to encrypt a column using aes-256-gcm encryption in PostgreSQL?

As a database point person, I am required to encrypt SSN numbers wherever they are in a table. We use PostgreSQL. My application counterparts require that we use the AES-256-GCM encryption algorithm. However, I am not too sure how to apply that in postgresql. After googling around, I am able to encrypt using either one of these two AES methods: 1\. UPDATE ssnTable SET encrypted_ssn = encrypt(encrypted_ssn::bytea, 'mykey', 'aes')` 2. UPDATE ssnTable SET encrypted_ssn = pgp_sym_encrypt(encrypted_ssn, 'mykey', 'compress-algo=1, cipher-algo=aes256') None of the above specifically uses the 'aes-256-gcm' algorithm, which is what I'm being asked to use. Any idea on how to use this algorithm on the column, in PostgreSQL?