Hi Xuelei,
After reading over your descriptions and the supporting documentation
this certainly seems like it would be a nice addition to JSSE. It
definitely seems like a performance win for QUIC and also for
bandwidth-constrained devices. I'm all for seeing this JEP proceed.
I'll likely have more comments down the line and I have taken a look at
the proposed code changes and will go back and do a deeper dive on it.
I just don't want to jump any of the JEP process hoops by talking about
code changes before some of the important first steps for the JEP have
been cleared. But you've got my support on this one!
--Jamil
On 3/7/2022 11:46 AM, xueleifan(XueleiFan) wrote:
Hi,
The TLS Certificate Compression standard was described in RFC 8879,
and has been enabled in browser Chrome and Safari. What’s TLS
Certificate Compression and what’s the benefits of this feature?
For TLS connections, a client must authenticate the identity of the
server. This typically involves verification that the identity of the
server is included in a certificate and that the certificate is issued
by a trusted entity.
Where servers provide certificates for authentication, the size of the
certificate chain can consume a large number of bytes. Controlling the
size of certificate chains is critical to performance and security in
QUIC. TLS certificate compression has the potential to ameliorate the
attacks/problems by reducing the size of the handshakes to a size
compatible with the security restriction. The TLS Certificate
Compression feature is an essential part for QUIC-TLS protocols.
For more details, please refer to section 4.4 in RFC 9001 (Using TLS
to Secure QUIC):
-
Note: Where servers provide certificates for authentication, the size
of the certificate chain can consume a large number of bytes.
Controlling the size of certificate chains is critical to performance
in QUIC as servers are limited to sending 3 bytes for every byte
received prior to validating the client address; see Section 8.1 of
[QUIC-TRANSPORT]. The size of a certificate chain can be managed by
limiting the number of names or extensions; using keys with small
public key representations, like ECDSA; or by using certificate
compression [COMPRESS].
and a more detailed description in the blog “Does the QUIC handshake
require compression to be
fast?”(https://www.fastly.com/blog/quic-handshake-tls-compression-certificates-extension-study).
I just copy part of the conclusion section of the bog here for your
quick reference.
-
First, the TLS certificate compression extension has a very large
impact on QUIC performance. Even though the extension is new and being
introduced fairly late in the process when compared to overall QUIC
deployment schedules, it seems quite important for both clients and
servers to implement the new extension so that the QUIC handshake can
live up to its billing. Without some help, 40% of QUIC full handshakes
would be no better than TCP, but compression can repair most of that
issue. I have heard of other non-standardized approaches to reducing
the size of the certificate chain, and they seem reasonable, but this
is a problem worth addressing immediately with the existing
compression extension.
...
Lastly, data from the real world again proves to be more insightful
than intuition and is invaluable in making protocol design and
implementation decisions. When I started this work I expected the
impact of compression to be positive but marginally focused on a few
edge cases. The data shows this optimization lands right on the sweet
spot that ties configurations and the QUIC specification together and
impacts a large portion of QUIC handshakes. My thanks to the authors
of the compression extension.
-
Besides, reducing the amount of information exchanged during a TLS
handshake to a minimum helps to improve performance in environments,
for example Internet of Things, where devices are connected to a
network with a low bandwidth and lossy radio technology.
This feature is a part to improve the performance of TLS connections,
and it is also a part of the path towards QUIC standards.
Chrome support TLS certificate compression with Brotil compression
algorithm, and Safari support TLS certificate compression with Zlib
compression algorithm.
In a summary, JDK could benefits from supporting RFC 8879 in the
following areas:
Performance - Reduce latency and improve performance of TLS and QUIC
connections by support the TLS certificate compression standard in JDK.
Security - Mitigate the impact of amplification attacks threat by
reducing the size of the TLS handshakes with compressed certificates.
What do you think? Do you want it a part of OpenJDK? Please feel
free to share you comments.
Thanks,
Xuelei
