TSEC (Tegra Security Coprocessor) is a controller used in most Tegra devices, including the Switch. Like many other controllers found in Tegra devices, it is powered by a Falcon microprocessor, but with additional crypto capabilities (via the SCP).
What you probably don't know is that this specific exploit would only work under certain circumstances (which won't be detailed for obvious reasons). While the 7.0.0 keys could be extracted this way, the 6.2.0 ones, for example, couldn't (as bizarre as that may sound).
Due to this, it was uncertain if keys in future updates could be extracted or not... Until now.
Third time's the charm. I found a critical design flaw a few weeks ago and after a short brainstorm session with
@SciresM, we were able to obliterate the TSEC's crypto scheme forever.
It only affects Switch manufactured before july 2018, has Nintendo patched the flaw in new units. It seems Nintendo won’t be able to patch this flaw via software anymore, at least they figure out the way the new exploit is working.