I like it - although pasting garbage in the field gets the same response as (presumably) a real private key. Doesn't specify what kind of private key either.
If you post your private key on this site it's not private anymore, so it should always answer it's not secure.
Thanks for pointing it out, all the fun and irony aside I bet someone might not get it, so I think we should be responsible and make it explicit that you should never, EVER post your private key anywhere. If you click "Check" it says:
"Why on earth would you post it here? Now it's surely not."
SERIOUSLY. THIS IS A JOKE.
DONT POST YOUR PRIVATE KEY ANYWHERE.
It was up until you clicked the Check button.
Thank you. Come again.
But if you asked for a public key, this would be safe and useful.
Bwa ha ha ha!
will be interesting to see how many have tried it actually. not the fake 9000 one .