We have now hardened our TLS to the highest level of security possible using available options, without resorting to extreme measures such as forking the code.
Server components: Debian Stable, Nginx, Let’s Encrypt TLS.
The security enhancements include:
- Removal of RSA ciphers, with a shift to ECC-only.
- Modifying the TLS certificate key and signature to ECC (instead of RSA):
- Key: EC 384 bits (the best available since P-521 is not supported by Let’s Encrypt).
- Signature: SHA384withECDSA.
- Disabling AES 128 in TLS 1.3 and 1.2, permitting only AES 256 (Note: there is no AES 512).
Additionally:
- OCSP Stapling
- HSTS
Questions you may ask:
-
Why didn’t you activate the OCSP Must-Staple certificate feature?
- Answered here.
-
Why you didnt activate DANE TLSA?
- Answered here.
-
Which TLS scanners do you usually use to check your TLS?
-
Why aren’t you achieving a 100% score on SSL Labs?
- Check discussion here.
If you know any websites that have implemented similar measures, please share them here.
Note: Please refrain from asking how to do it here; instead, use a search engine.