The proposition is that the NSA has a large black budget, and it could plausibly have done the math to unwind DH with the most popular 1024-bit DH primes, and certainly would be able to do this for 512-bit DH.
Nobody does this in 2021. Your browser is using X25519 which is the same concept but with Elliptic curves instead of modular exponentiation of integers.
If Steam were concerned about certain TLS parameters, they could just ensure they never agree the worrying parameters. It wouldn't make any sense to instead bake some other mechanism for login and then trust TLS for everything else.
https://weakdh.org/
The proposition is that the NSA has a large black budget, and it could plausibly have done the math to unwind DH with the most popular 1024-bit DH primes, and certainly would be able to do this for 512-bit DH.
Nobody does this in 2021. Your browser is using X25519 which is the same concept but with Elliptic curves instead of modular exponentiation of integers.
If Steam were concerned about certain TLS parameters, they could just ensure they never agree the worrying parameters. It wouldn't make any sense to instead bake some other mechanism for login and then trust TLS for everything else.