A security researcher has predicted SHA 256 will be cracked this year. When that happens the algorithm may change.
Cite? There are not even any "academic attacks" against SHA-2 at this time. An academic attacking being a method which is faster than brute force but still computationally infeasible to exploit in the real world.
Er,
Let's all be clear that bitcoin utilizes DOUBLE SHA-2 before making bold statements.
Actually there are partial attacks that are very well documented against SHA 2 upto about 25 bits , but not so much against double SHA 2....
The other issue is that the research into SHA 2* attack vectors has a weakness.....(which you can figure out yourself if you think about it....)
Plus there is some VERY interesting shit if you can program up your own FPGA farm..... The big issue is getting the shit out fast enough...
It isn't a bold statement, it is merely a statement of fact. Lets ignore the potential added security of double SHA hash and just focus on single SHA-2 hashes.
SHA-2 uses 64 or 80 rounds. There are no known attacks against 64 or 80 round SHA-2. None. No first preimage attacks, no second preimage attacks, no random collisions.
This isn't for a lack of trying. SHA-2 is one of the most analyzed algorithms in the world. It is used for just about everything from banking to PGP to SSL. A lot of different entities in a lot of different places all around the world have a very vested interest in knowing if SHA-2 is secure. Cryptography can never be mathematically proven secure, the best we can do is (collectively) look for flaws and if enough people look hard enough for long enough the probability that an unknown flaw will appear suddenly and without warning is reduced, never eliminated but reduced.
An academic attack on a theoretical variant of SHA-2 which uses 41 instead of 64 rounds isn't an attack vector unless Bitcoin happens to use this modified variant with 41 instead of 64 rounds. For the record it doesn't, nobody does, anywhere, for anything. Publishing a reduced round version of an attack is essentially saying "we looked for a flaw but couldn't find one however
if this algorithm only used x rounds instead of y rounds here is a flaw". It is a way for other researchers to potentially expand upon but often many of these reduced round attacks are simply dead ends. What works for 41 rounds may NEVER work for 64 rounds. It is possible that these known reduced round attacks are dead ends. That is to say that eventually SHA-2 is broken but it is broken in a completely unrelated manner and researchers who will try to expand on these known attack vectors will spend countless hours it what will ultimately prove to be "barking up the wrong tree".
I never predicted that SHA-2 won't eventually be broken but to claim it will be broken this year requires some significant supporting evidence and none was provided. When asked for a cite, link to tweets unrelated to the claim were provided. When confronted the person left saying he "doesn't need to prove anything to anyone". That isn't what I would call "significant supporting evidence".
Maybe SHA-2 will be broken this year, or maybe next year, or maybe it is never broken because over time most applications migrate to SHA-3 (after significant cryptoanalysis) because it has less theoretical flaws. If that happens a exploitable flaw in SHA-2 may never be found because the focus of global analysis will shift to SHA-3 as it will be the bigger target.
To make a long story long regardless of if/when SHA-2 is broken the statement that "it will be broken by the end of the year" is rubbish. Nobody credible said that, and nobody credible would.
