Just wondering...am I wrong in assuming -
Yubikey 4 - secure and dope as fuck
Trezor - secure
Stamps.com... - probably a honeypot or at the very least extremey risky
HD Wallets - Cool but probably a chance someone can extrapolate all of your wallet address from one single address, possibly a need to scrap them after (each?) multiple uses?
Bonus : If you have a regular wallet, lets say a cold storage wallet you printed out with entropy or something like that, can you take the long ass key and convert it to the 12 words? Are the 12 words a "one way" thing?
Bonus YES its like a seed for electrum