Yes, because they know the IPs your packets go to, but if there are multiple websites behind a single IP they won’t know which one (unless you use your ISP DNS server, which you should probably not)
That’s not true. Almost all TLS clients use SNI to send the server name in plaintext, so the server can present the right certificate. With QUIC/http3, this is no longer done in plaintext, but the packet is still being sent alongside the initial encryption key so anyone with access to the traffic can simply decrypt these packets.
There are trials out there for ESNI/ECH, which encrypts the SNI fields in a way the ISP can’t read, but those are far from stable, not implemented by most web servers, not enabled by default by web browsers, and require additional setup for website admins (read: won’t be widely implemented for another five to ten years).
The URL and Host header are encrypted of course. Your ISP can find out you’re going to youtube.com, but not what video you’re watching.
Oh, thanks for this precision, I wasn’t aware of this. And now that I think of it, it’s obvious that the first exchange with a server has to be unencrypted
That’s not true. Almost all TLS clients use SNI to send the server name in plaintext, so the server can present the right certificate. With QUIC/http3, this is no longer done in plaintext, but the packet is still being sent alongside the initial encryption key so anyone with access to the traffic can simply decrypt these packets.
There are trials out there for ESNI/ECH, which encrypts the SNI fields in a way the ISP can’t read, but those are far from stable, not implemented by most web servers, not enabled by default by web browsers, and require additional setup for website admins (read: won’t be widely implemented for another five to ten years).
The URL and Host header are encrypted of course. Your ISP can find out you’re going to youtube.com, but not what video you’re watching.
Oh, thanks for this precision, I wasn’t aware of this. And now that I think of it, it’s obvious that the first exchange with a server has to be unencrypted