Cryptography How easy is it to break my hash?

How easy is it to break my hash?
XTS-AES-128 w/256 bit key vs AES-256
ELI5: How would quantum computers defeat modern encryption?
How would you encrypt folder names? (Considering the name's length shouldn't increase because of OS restrictions)
Unique signature scheme to use as a basis for Verifiable Random Functions?
How can you sign things with a https key other than for point to point crypto?

Posted: 21 Feb 2018 11:02 PM PST

22/2/18: Made mistake, its actually a potential one-way function not a hash

So I decided to make a very simple one-way function which I could do without a computer. As far as I can see, the hash is collision less and somewhat hard to detect a pattern. The ~~hash~~ one-way function is particularly weak with small numbers and with ones ending with multiple zeros. You can also reduce the bruteforce length by counting the number of digits and estimating it's range but that's all I could find.

I was hoping r/crypto could find more vulnerabilities.

It'd be impressed if you could find the input of 73740945964519364892687222629632

Here's everything you need to know about the ~~hash~~ potentially one-way function:

You can test out the function and see it written in some popular languages here.
This might be useful if your looking for a pattern. (There's a very obvious one from about 1-170)
Here are the steps manually:

Cube the input number, e.g 5³ = 125
List each digit and identify the prime digits (except 1):
1st - 1
2nd - 2
3rd - 5
Move all prime digits to the top of the list (remember this new order):
3rd - 5
2nd - 2
1st - 1

New order: 3rd, 2nd, 1st
Multiply the cubed number by 3, e.g 125 x 3 = 375
List the digits from the multiplied number:
1st - 3
2nd - 7
3rd - 5
Reorder them in the order from step 3:
3rd - 5
2nd - 7
1st - 3
Turn the list back into a number and that's the output, e.g 573

submitted by /u/BoxDoggy
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XTS-AES-128 w/256 bit key vs AES-256

Posted: 21 Feb 2018 03:51 PM PST

Hey all. Simple question that I can't find the answer to. How does XTS-AES-128 w/ 256-bit key compare to AES-256 bit standard?

submitted by /u/Ludeth
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ELI5: How would quantum computers defeat modern encryption?

Posted: 21 Feb 2018 09:50 AM PST

How does the quantum computer decrypt compared to modern decryption? How can it be so much faster etc?

submitted by /u/Sergeant_Savage_
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How would you encrypt folder names? (Considering the name's length shouldn't increase because of OS restrictions)

Posted: 21 Feb 2018 07:16 AM PST

So, I'm creating this file encryption tool with Node. It's looking good, but I've realised that when I try to encrypt the folder names I get really long strings (IV:hex).
I'm thinking of creating my own word scrambling algorithm.
What would you do instead?

submitted by /u/Speckart
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Unique signature scheme to use as a basis for Verifiable Random Functions?

Posted: 21 Feb 2018 11:48 AM PST

In the cryptocurrency paper "Algorand", Micali builds on a primitive: verifiable random functions, which are in turn built upon unique digital signatures. He doesn't specify what particular unique signature scheme he intends us to use.

Now, I only know about two unique signature schemes: RSA-DSA, and BLS. Unfortunately, I've heard that BLS has had some vulnerabilities discovered recently. I've also recently asked on this subreddit about whether or not RSA is still a viable choice and the answer I got back was basically "it's really hard to get right, because there are so many attacks."

So my question is: are there any other unique signature schemes that are ... uh... more robust?

submitted by /u/joshyelon
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How can you sign things with a https key other than for point to point crypto?

Posted: 21 Feb 2018 04:32 PM PST

submitted by /u/BenRayfield
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