Do you guys think SHA256 obsolete and is it enough to guarantee security?
It's too secure. The number 2
256 may not say much, but an example I had seen on a video might give you a taste.
2
256 is 2
32 multiplied with itself 8 times. To round things up, let's just use 4,000,000,000
8. A GPU can calculate a little less than 1 billion hashes, but let's assume that you've bought enough and have crammed your computer with them to achieve the 4 billion hashes per second.
So the first 4 billion will represent the
hashes per second per computer.
(4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion)
The next 4 Billion would be the total computers like the one above. Google owns some millions of servers that are much less powerful than that computer, but let's say that they replaced them all with a machine like this, referenced as
KiloGoogle. Four billion machines would mean about a thousand copies of Google's possession.
(4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion)
There are around 8 billion people one Earth. Picture
half of them owning a KiloGoogle.
(4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion)
Imagine that on our Milky Way, there were
4 billion copies of the Earth where half people on each Earth had their personal KiloGoogle.
(4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion)
Let's assume the existence of
4 billion Milky Ways with these characteristics. We've now reached 2
160 per second.
(4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion)
Four billion seconds are around
126 years and if you also
multiply that with 4 billion, you get 507 billion years, which is about 37 times the age of the universe.
(4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion) (4 Billion)
So even if 4 billion people used their KiloGoogle on 4 billion different Earths of 4 billion different Milky Ways, it'd take 507 billion years to cover the 1/4,000,000,000 of the total hashes. I think it's secure.
[Link for the video: How secure is 256 bit security?]