The AES-GCM mode of operation turns the AES block cipher into a stream cipher. Doing this makes it possible to add authentication on top for relatively cheap. T

The AES-GCM mode of operation turns the AES block cipher into a stream cipher. Doing this makes it possible to add authentication on top for relatively cheap. The ChaCha20-poly1305 has a similar construction. These are the two most secure and efficient ciphers available in TLS, so they get a lot of use. If you are sending documents over HTTPS, you definitely want them encrypted with one of these two.