I am writing a program in which I am using NumericQ. I am trying to allow symbols to also be considered Numeric, so I have been using NumericQ[a]=True for all of the symbols that I want to be numeric. However, this messes with the functionality of Solve so that I have to write NumericQ[a]=False for all of the symbols before using Solve. Going back and forth repeatedly, even using a map function, is annoying. To solve the issue, I created a new function defined by numeric[x_Symbol]=True; numeric[x_?NumericQ]=True; numeric[___]=False;. The issue with this method is that I want numeric[b+5] to evaluate as True. For example, when you type NumericQ[c]=True; NumericQ[c + 7]; evaluates to True. Initially, I added a line for every operation between symbols that I wanted to be True —Plus[x_?numeric,y_?numeric]=True. Even just adding Plus made the code significantly slower, but adding it for all of the operations – Times, Conjugate, Exponent – made it too slow to evaluate. My code makes extensive use of NumericQ, so I need whatever I use to not be much slower than it if I want it to run in a reasonable time. Thank you for the help.
Assuming SHA256 isn’t broken, this isn’t possible in Bitcoin, as the only way to find data that hashes to the same thing is when the data is the same. Since every Bitcoin block contains a hash of its parent, and thus indirectly commits to its entire ancestry, blocks with distinct history will always have distinct contents.
This is probably the case for many similar and not too similar systems as well, but it’s hard to answer generically as the term blockchain tends to be very loosely defined only. It’s also off topic here.
I know it’s almost impossible to do, SHA256 is a one way function that can’t be easily reversed, just like there are operations that have no reverse, take:
f(x) = x+5 , it’s easy to see that if you want to revert that you just take the output and substract 5, you’ll get the original input, the reverse would then be f(y) = y-5
For f(x) = 7, there’s nothing you can do about it, no matter what X is, you always get 7, you can easily input any X, get the output, and get 7, but to gt the original input, there are infinite possibilities.
Similarly, sha256 can’t be unhashed because of this, mod operator has no inverse, for example, yet, there are ways around that, what I mean is, 22%7 is 1, 7 ? 1 = 22, no operator for that, but I can take a set of numbers that when moded with 7, x%7 = 1, this is still infinite, but this infinite is smaller than all N numbers.
So, would it be possible to try to unhash a sha256 making a list of “candidates” or finding some rules about the seed that lead to that hash?
When I was thinking about this, I found this really interesting research on github
I’m a newcomer in this world, but now I feel very interested on ways to unhash a sha256 other than brute forcing which is not unhashing, is just hashing everything until a match.
What other ways are known that are not brute-forcing? Is really that the only approach there is?
We’re looking to host our documentation, UI library and possibly code in one place and need something like InVision DSM, but don’t want to be locked into the Sketch/ InVision ecosystem in case we switch to Figma/ XD in the future.
Right now we have our UI kit in Sketch, our documentation in OneNote, and our code on Vercel. Any thoughts on a low cost/ low maintenance solution?
I was wondering if you know any software that I can install in my CPanel server
for making upload speed tests in a similar fashion … | Read the rest of https://www.webhostingtalk.com/showthread.php?t=1847656&goto=newpost