# Gavin Andresen
# 2010-10-28 18:48:09
# https://bitcointalk.org/index.php?topic=1514.msg19049#msg19049

I wonder if we have already passed the point where a user-typed-in-arbitrary-key can be both secure from brute-force attacks and convenient to use. @p{par}

If you make the key long enough to prevent brute-force try-every-possible-key attacks then typing it in gets really painful. @p{par}

You can add proof-of-work, but attackers tend to have lots of CPU power (think botnets) and lots of time, and if you make the proof-of-work take more than a few seconds per attempt on a low-CPU device it gets really painful again. @p{par}

I'm thinking some variation of wallet-on-a-USB-stick might be a more convenient and practical way of physically exchanging bitcoins. @p{par}

I wonder if Ebay would let you sell USB sticks pre-loaded with Bitcoin, a snapshot of the block chain, and a "starter wallet" with X bitcoins in it... @p{brk}