This paper basically explores a hypothetical scenario where scaling quantum memory ends up being cheaper than scaling computational qubits. The title (or abstract) unfortunately does not mention the quantum memory requirements at n=2048 explicitly.<p>For factoring 2048 RSA integers, the technique proposed in the paper would require ~430 million memory qubits (see the table at top of page 16).
I fear it is my obligation to point out this excellent screed by Scott Lockin: "Quantum computing as a field is obvious bullshit". A beautiful excerpt from the article:<p><i>When I say Quantum Computing is a bullshit field, I don’t mean everything in the field is bullshit, though to first order, this appears to be approximately true. I don’t have a mathematical proof that Quantum Computing isn’t at least theoretically possible. I also do not have a mathematical proof that we can or can’t make the artificial bacteria of K. Eric Drexler’s nanotech fantasies. Yet, I know both fields are bullshit. Both fields involve forming new kinds of matter that we haven’t the slightest idea how to construct. Neither field has a sane ‘first step’ to make their large claims true.<p>.....<p>“quantum computing” enthusiasts expect you to overlook the fact that they haven’t a clue as to how to build and manipulate quantum coherent forms of matter necessary to achieve quantum computation. A quantum computer capable of truly factoring the number 21 is missing in action. In fact, the factoring of the number 15 into 3 and 5 is a bit of a parlour trick, as they design the experiment while knowing the answer, thus leaving out the gates required if we didn’t know how to factor 15. The actual number of gates needed to factor a n-bit number is 72 x n^3; so for 15, it’s 4 bits, 4608 gates; not happening any time soon.</i><p>[1]: <a href="https://scottlocklin.wordpress.com/2019/01/15/quantum-computing-as-a-field-is-obvious-bullshit/" rel="nofollow">https://scottlocklin.wordpress.com/2019/01/15/quantum-comput...</a>
The authors hide the fact that this would require millions of memory qubits (which need to be as accurate as the normal qubits), so the title is a bit misleading IMHO.
One day you can start calculating private keys based on public keys.<p>This is the biggest crypto puzzle: find private key of Sathoshi Bitcoin wallet with 1 mln bitcoins. Over $50 Bln prize for one crypto puzzle.<p>This would be AlphaGo moment of quantum computing if you could make that one attack successful even while paying huge price (e.g. years of quantum datacenter work).
This reminds me to listen to MC Frontalot's Secrets from the Future again. If you haven't heard it yet, you're in for a treat! <a href="https://youtu.be/FUPstXCqyus" rel="nofollow">https://youtu.be/FUPstXCqyus</a>
layman here. i understand that if said theoretical computer did exist, encrypted stored data using today's standards is for the most part compromised, outside of further obfuscation, which the popular opinion seems to believe only helps so much.<p>that means the past is compromised, with some amount of implementation afterwards. i've always wondered just how much the future is compromised.<p>i've always thought about encryption this way:<p><pre><code> P = some degree of computational power
A = some small unit of P, like a laptop
B = the largest unit of P practically
possible under the same laws of physics as A
(data encrypted by A cannot be "cracked" by B in a reasonable amount of time)
</code></pre>
so in my head, so long as a normal civilian can access qubit technology (likely questionable), encryption still works by increasing the number of rounds. what am i missing?<p>edited for format, then again for clarity
Quantum computers of this scale are probably 5-15 years out. Basically this is a warning that if you have secrets that should still be kept secret over that timeframe, you should not be using RSA today.
It's an interesting theory but like most items in quantum computing it is purely theoretical. Not sure how much it would cost to build.<p>I hope someone gets a grant to work out the engineering difficulties in this.
Could anyone take a stab at the cost of such a computer, if it were possible to build today? Like, I know there are computers of <100 qubits, but how much does one cost?