Your **super super secret key number** can only ever be "seen" through some "mask"

nsec is one kind of mask, the default for nostr keys.  hex is another.  binary, english, etc, other possibilities.  Humans in our heads default how we mask stuff to base 10, decimal, in our routine thinking & daily affairs, because of fingers I guess 😏.  For nostr, nsec makes more sense for a bunch of reasons

It doesn't matter which mask someone sees the ***I can't stress how secret it is*** number through;  they can always translate it once the secret is seen through any encoded form!  English to binary is how computers work today after all, they can do a lot more "mask switching" than that 😉

Keep the secret, secret!   

 What do you think is the best tool to use to keep it a secret secret? 

 It depends how you use your account.  I'd say browser extensions like #alby are fine for most.  #Amber on android serves the same purpose for android apps, but is more private (no 3rd party account).

The idea is to only paste your secret key into one trusted place, and let every other app ask that app to sign your events for broadcast.  

 one more question: what is the browser extensions giving to clients and apps....is it something even more difficult than a HEX? 

 Everything in computers is encoded in binary with 1s & 0s.

But to answer, the extension doesn't give your secret to apps at all.  The other way, apps will say to the extension "sarah wants to post this recipe, please 'sign' it so I can post it to the relays and they know its from the right account"

The secret never leaves the extension.  Once you paste the secret into the extension to store it, you really shouldn't paste it into anything else (except another trusted thing like amber). 

 I have been using KeePass for years. (now KeePassXC). 

its probably better then pasting it in a word file on your desktop... 

 tyty, i will look at!!