Ripple's 128 bit master seed, how long can the "root master key" stay secure ?

[alexkravets]

Ripple wiki specifies that each key family originates with (presumably) 128 bit master seed https://ripple.com/wiki/Account_Family

How much energy and time must be expended before ASICs custom hardware can brute force attack a 128 bit key ?

Good overview is given here: http://en.wikipedia.org/wiki/Brute-force_attack

TL;DR version is that it would require at least 30 gigawatts of power for one year. perhaps too much to attack your Grandma's ripple key pair, but what about ripple network's own master root key or the master root key of OpenCoin, Inc. in say 10 - 20 years ?

Having read the above two articles, I would prefer the master key to be at least 160 bit of good entropy, although it would make for a longer base-58 encoded sXXXXX representation, but Bitcoins secret keys carry close to 256 bits of entropy and that hasn't proven to be too cumbersome.

So, can ripple network survive another 50 years of ASICs custom hardware evolution ?

[Ente]

hmm.. what would it effectively mean, if the key or a collusion was found?
No "user"-keys can be retrieved from this. So *my* stuff is safe.
What would be the implications?

And nah, 128 bit isn't that bad anyway ;-)

Ente

[markm]

They would have to move their hoard of XRP to a new account every decode or few years or even just make moving it a regular yearly ritual. No big deal.

-MarkM-