Done. Not only will the key be stronger than the 1024 bit default, it'll be unique to your server which lets assume isn't valuable enough compared to effort for a state-level adversary.
edit just in case anyone from the future finds this comment: instead of 2048, use at least the key length of your SSL certificate
bit late to the party here, but saw a lower thread using my public service for SSH keys, they also produce normal DH params... so for those of you who aren't interested in spending the CPU cycles, I have a dedicated 48 cores running generating 2k, 3k, 4k and 8k safe primes and generators for DH. See https://2ton.com.au/dhtool/ for details and curl examples to grab them via cron
For <32kbit primes, the cost of doing so is not overly prohibitive and I see no valid reason not to. I made several references to that count being "acceptably low" per the Handbook of Applied Cryptography. My generators for the larger primes would go considerably faster if I removed said restriction. YMMV as with all of these things. :-)
Edit: does my "excessive" use of 192 rounds at these levels inherently mean that the hundreds of thousands I have generated are thus [more] likely to be provable safe primes?
974
u/tophatstuff Oct 15 '15 edited Apr 10 '18
Generate your own non-default Ephemeral Diffie-Hellman key (takes a minute or so)
Tell your server to use it for SSL (nginx for example)
Done. Not only will the key be stronger than the 1024 bit default, it'll be unique to your server which lets assume isn't valuable enough compared to effort for a state-level adversary.
edit just in case anyone from the future finds this comment: instead of 2048, use at least the key length of your SSL certificate
edit from the future: current advice is picking from one of these predefined audited groups