http/2.0 sslciphersuites with 256 bit alias crypto wars part eight TLSv1.3

Now with the release of Apache 2.4.37 it supports TLSv1.3 (with OpenSSL 1.1.1). Before is was possible to compile Apache against OpenSSL 1.1.1 but it had no effect compared to OpenSSL 1.1.0

There are some advantages using TLS 1.3. it comes with Zero Round Trip Time (0-RTT). Explained simply, with TLS 1.2, two round-trips had been needed to complete the TLS handshake. With TLSv1.3, it requires only one round-trip, which in turn cuts the encryption latency in half. It feels faster.

At the moment only Chrome and Firefox support TLS 1.3. But I think other browser will follow soon.

This requires Apache 2.4.37 or better and OpenSSL 1.1.1 or better. Note that there are now two different directives for SSLCipherSuite. Also new is that the names for the Ciphers for TLS 1.3 areĀ  directly taken from the OpenSSL internal naming. This is different compared to the old way in apache. Only two ciphers that are allowed for TLSv1.3 support 256 bit encryption that is why I chose those.

Listen 443
<If "%{SERVER_PORT} == '443'">
<IfModule mod_headers.c>
Header always set Strict-Transport-Security "max-age=15553000; preload"
</IfModule>
</If>

ProtocolsHonorOrder On
Protocols h2c h2 http/1.1

TraceEnable Off

SSLUseStapling On
SSLSessionCache shmcb:/opt/apache2/logs/ssl_gcache_data(512000)
SSLStaplingCache shmcb:/opt/apache2/logs/ssl_stapling_data(512000)
SSLOptions +StrictRequire +StdEnvVars -ExportCertData
SSLProtocol -all +TLSv1.2 +TLSv1.3
SSLCompression Off
SSLHonorCipherOrder On
SSLCipherSuite SSL ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA
SSLCipherSuite TLSv1.3 TLS_CHACHA20_POLY1305_SHA256:TLS_AES_256_GCM_SHA384

SSLOpenSSLConfCmd DHParameters "/opt/apache2/conf/dh4096.pem"
SSLOpenSSLConfCmd ECDHParameters secp384r1
SSLOpenSSLConfCmd Curves sect571r1:sect571k1:secp521r1:sect409k1:sect409r1:secp384r1:sect283k1:sect283r1:secp256k1:prime256v1

H2Direct On

Sadly not OS Distributions support the last OpenSSL version or that TLv1.3 version has been backported or it has been patched, but apache shows still an older version number.

One thought on “http/2.0 sslciphersuites with 256 bit alias crypto wars part eight TLSv1.3

  1. I don’t think 0 RTT is so secure, since the same PSK is used over and over again. So in the future that might be disabled in OpenSSL. For apache at this moment (2.4.37) there is no harm, since it doesn’t support 0-RTT.

Leave a Reply

Your email address will not be published. Required fields are marked *