Re: The case for moving from a 160 bit to a 256 bit Bitcoin address
Yes, 2^80 is still a lot of work-- which is why I didn't just do it to make an example in a response. 
But it is not an infeasible amount of work: 2^80 work by Bitcoin is paid for by less than three days of mining income-- $14,580,000-ish.
But who are you to decide that the maximum value of of a Bitcoin exchange should be limited to under (say) $15M? Personally, I'm gunning for the day where a single Bitcoin is worth that much.
(otherwise, I dunno how I'm going to finance both a space elevator and the invention of human immortality)-- and what about next year? With 2^80 work perfectly achievable though expensive now where will that cost be next year and the year after? We saw with P2SH that it takes _years_ to adopt a new address type in Bitcoin. "By 2025 a children's speak and spell could crack it" (perhaps not, but the point remains)
Being weak in this way is just fodder for conspiracy theories and arguments that Bitcoin will lose its value in the future. This sort of weakness makes life harder for application developers since there are more corner cases which they cannot dismiss as categorically infeasible. Between these, security against near future decreases in computational costs, and security for large values-- 12 bytes of additional public key size is a pretty low price to pay.
But it is not an infeasible amount of work: 2^80 work by Bitcoin is paid for by less than three days of mining income-- $14,580,000-ish.
But who are you to decide that the maximum value of of a Bitcoin exchange should be limited to under (say) $15M? Personally, I'm gunning for the day where a single Bitcoin is worth that much.
(otherwise, I dunno how I'm going to finance both a space elevator and the invention of human immortality)-- and what about next year? With 2^80 work perfectly achievable though expensive now where will that cost be next year and the year after? We saw with P2SH that it takes _years_ to adopt a new address type in Bitcoin. "By 2025 a children's speak and spell could crack it" (perhaps not, but the point remains)Being weak in this way is just fodder for conspiracy theories and arguments that Bitcoin will lose its value in the future. This sort of weakness makes life harder for application developers since there are more corner cases which they cannot dismiss as categorically infeasible. Between these, security against near future decreases in computational costs, and security for large values-- 12 bytes of additional public key size is a pretty low price to pay.