[howdoibtc]

I found the key as well, also used Electrum, and also was (seemingly) unable to do anything with it.

Turns out, you have to prefix the private key with "p2wpkh:", or else it imports it as a legacy key, and generates a completely different public hash.

[redactsure]

What did you try to do? If you had the full key it should be relatively simple. Maybe I should post some instructions on claiming the key?

[howdoibtc]

Launch Electrum, create a new wallet, "Import Bitcoin addresses or private keys", paste in the recovered key.

If you just paste the raw key, Electrum uses a legacy format, and none of the transactions show up for that private key. Adding the "p2wpkh:" prefix to the key makes the transactions show up, but I realized that well after someone else claimed it.

I don't know if this is an Electrum thing, if this is considered general knowledge now for those who regularly use BTC, or if it's a quirk of how BTC has evolved.

[redactsure]

that was brutal! I knew you were holding out something. Oh man this is a brutal bug as well. That's an OS popup! That's gonna take me some time.

Actually even worse it's neither an OS level or dom level item custom chrome rendering layer.

[howdoibtc]

That explains why the validator error looked entirely different when I tried to reproduce it locally -- I was wondering about that.

And yeah, it's a CTF, gotta hold onto issues until the flag redemption is back up.

[redactsure]

bet you couldn't do it again. It's back up. Patch is a bit hacky but should work plus I blocked the signup page.

Real patch is a chromium update (like a week of work) so imma avoid that until needed.

[redactsure]

back up if you want another chance

[howdoibtc]

Got it :)

Pasted the private key into the email address field on the Wufoo signup page, and the validator helpfully told me my "email" was invalid, with the whole key included.