Chrome currently supports encrypted push message payloads encrypted with the `aesgcm` content encoding (draft 03). A series of substantial changes were made to the encryption drafts, yielding a new content coding: `aes128gcm` (draft 08). We'll continue to accept `aesgcm` for received push messages as well.
Docs: https://tools.ietf.org/html/draft-ietf-webpush-encryption-03 https://tools.ietf.org/html/draft-ietf-webpush-encryption-08