Do that for rate limiting and it'll be super easy to DoS you - just show how fundamentally you can't brute force your way out of algorithmic questions despite the article suggestion (or how interviews are fundamentally flawed, but this is another debate ;)
> The function should have expected O(1) performance.
> Do that for rate limiting and it'll be super easy to DoS you
How so? The rate limiter has the same performance as, for example, a hash table. Operations are usually O(1), but are periodically O(n). It's not like every service that uses a hash-table is DoS-able.
Geniusly curious: does "expected" in English necessarily means average? My understanding was that expected is dependent of the application domain, so it can mean best or worst or average.
If you have an implementation that is O(N) in worst case it's (theoretically) DoSable since an attacker would always hit that case - so the expected complexity in case of an attack is O(N).
A trivial solution in O(60)=O(1) for worst case is to store the number of call everything second in a fixed size array and loop over it. With some arithmetic you can even avoid looping over it.
Ethereum is, what, 6 years old. Metamask has been in development for 5 years. Bitcoin is 12 years old.
Bitcoin is older than React.js. Ethereum has been around for as long as TikTok. Uber was founded in the same year as Bitcoin and has essentially destroyed a worldwide industry.
At some point these things aren't young or early, they're just stupid.
Technologies mature at different rates. ARPAnet was created in the 1960s. www was created in 1989. Yahoo & Netscape were started in 1994. Foundational infrastructure is rarely explosive in growth.
It's also unclear how you're measuring success. By market cap, Bitcoin beats out all three of your examples (React, TikTok, & Uber). But it's also a bit weird to compare Bitcoin to two of the fastest growing consumer companies in recent memory. It's apples & oranges.
They haven't 'found' a single practical use case other than for some speculators who think they have a 'store of value'.
Reading this thread it's clear Web3 doesn't really have a use case either, it's more like a concept.
These have many parallels in industry - there are tons of products that never got made because they didn't make a whole lot of sense even though they were cool. The difference being, people can chose to spend their own time on these things now if they so choose and a lot of people do.
It's like a distributed technical artistic counter-cultural social movement except the artists believe they're doing something more practical than they probably are.
I don't know about America, but when comparing payment infrastructure in Europe vs. Asia, I'm always amazed at how bad the EU is.
Hoping that this will work but I highly doubt it - most European banks were created a very long time ago and like all legacy systems it's really hard to change their habit.
Even if I'm using this "immediate payment system", I'm pretty sure my local bank will still delay my payment by a few days "because they are used to do it that way".
I moved from Finland to UK to USA, so I have personal experience with three rather different banking ecosystems.
The payment systems in America are literally 30+ years behind Finland and UK. It's absurdly bad. People still send paper checks. There's no national infrastructure for bank transfers. You shouldn't give out your bank account number to anyone (unlike EU/UK where it's perfectly safe to post account numbers). Direct debit seems crazy unregulated.
Credit cards and bank-specific transfer systems are used to patch the most glaring holes in this mess, which I'm sure pleases Visa/Mastercard and the banks themselves, but leaves everyone else worse off.
The US Federal Reserve is implementing Instant Payments in 2023 [1]. The system is already in beta testing [2], and its development is ahead of schedule [3], going live a full year earlier than first projected. Fintech sees the writing on the wall with Paypal moving into crypto and brokerage services, and Visa attempting to acquire Plaid to move away from payments. Payment revenue is going to (rightfully so) plummet as the Fed fixes antiquated plumbing and drags the US into the 21st century (54 other countries already have instant payment systems [4]).
One would expect banks and the Fed to eventually adopt similar infra that Europe is (per this submission), where card infra can use these Instant Payment ("FedNow") rails for C2C, C2B, and B2B payments (although, eventually, everyone will move to QR codes a la China; Zelle is beta testing QR code support for instant payments on their network [5]).
US payments currently suck, but I wanted to share that progress is being.
This is a good update, than you for the resources.
One only point to add to your last one: Revolut, already very popular in Europe, is also present in USA now. QR codes are already supported, as well as instant phone to phone payments with either phone number, name alias (uniqueID).
But that's only within Revolut, which is a very small fintech compared to the aggregate of commercial US banks. Why would I use Revolut when I can use a US bank that supports Zelle today, or any US bank that will support Instant Payments in 18 months?
Also, Wise today supports cross border P2P payments and are a more reputable firm than Revolut. I would recommend Wise over Revolut if someone was looking for such a feature.
From my perspective none of the things you list are really problems in my life.
* I don’t even own checks and if I get one I take a photo from my banking app and have it deposited.
* I only use my debit card for the very rare times I withdraw cash and instead just use a credit card that auto-pays from my bank directly each month in full.
* If I want to transfer money between friends I just use Venmo.
* I’ve never had fraud issues but my sister had her card skimmed in Europe and calling to report was enough to reverse the charges.
Well, for an anecdote, the process of renting an apartment was considerably easier in UK when it came time to send in payments.
In London, once I'd signed a lease, the rental agency simply gave me account numbers for the deposit and other fees. I sent the payments to UK from my Finnish bank account at no extra cost (bank transfers within the EU/UK payment area are free).
In New York, once I'd signed a lease, the rental agency told me I need to bring them seven cashier's checks by Monday for the deposit and various fees going to different destinations (condo management corporation, etc.) At this time I was in London, so shuffling physical pieces of paper from a bank into an office in NYC wasn't going to happen! Kindly the agency agreed to allow me to wire them the total sum, and they would "cut" the checks for a mere $15 / check. For seven checks, that was an extra $105 fee — for nothing really except to work around a system still built on 19th century assumptions of money. (I also had to pay fees to send the wire transfer, because Americans somehow believe that bank transfers cost tens of dollars to process.)
Additional patchwork layers like Venmo don't solve these issues. Sending thousands of dollars to a landlord or management corporation isn't the same as sending $50 to a friend for dinner.
I had to pay a bill by typing numbers into an online bank along with an address that the physical check would then be mailed to.
I thought the banker who told me they would send a check was joking. Or just using it as an metaphor for making a payment to the account. But no, at one point the check actually got lost and and then reappeared later so my balance with PG&E went positive.
Oh, and it could only pay fixed amount at regular intervals.
I eventually learned that most vendors would accept check numbers, and then magically withdraw from my account. So long as a checked a box that effectively allowed them to withdraw whatever they deemed I owed them.
In Denmark I get an electronic statement of all the bills I have signed up for automatic payment. It just works.
Oh, not to mention: to rent an apartment in the US I had to get a cashier's check. I'll admit I didn't even know that was a thing...
I’m sorry that happened but that sounds like a problem with PG&E rather than a banking problem, surely they can accept other forms of payment —- For example, I just pay my utility bills on auto pay from a credit card each month.
For renting I directly had monthly deposits drawn from my bank account after providing a routing/account number to the landlord. I lived in four different apartments and all of them just directly withdrew from my bank account automatically each month. Even for an initial deposit it was directly transferred from the bank or put of a credit card.
I've lived in the US and UK and generally agree with you. But one thing that got me is that it seems fairly easy to defraud the system in the UK with everyone so freely giving out their bank account numbers.
What actually protects the bank account numbers in the UK/EU? Why do people seem totally unconcerned with giving out this information there?
What bad can you do with someone's IBAN account number? Nothing, unless a bank is somehow totally incompetent.
It's basically the same as an email address. You can't read someone's email inbox just by knowing their address. Similarly, you can't send money out of a bank account just by knowing the number. (You could spam them with money, but most people wouldn't mind.)
Banks by EU law have to comply
with SEPA / instant payments. Payments in Europe is very good compared to US and in most cases also better than Asia. After all, Europe invented open banking and PSD2.
Asia is very fragmented. Countries like China, HK and Singapore are very good on instant payments, in particular because card payments have very high MDR and fees. Other countries like Indonesia and Philippines are just now starting to implement fast payments and national clearing infrastructure. And, unlike Europe, cross-border payments are still highly fragmented and expensive.
> I don't know about America, but when comparing payment infrastructure in Europe vs. Asia, I'm always amazed at how bad the EU is.
Europe, Asia, EU... why make such meaningless generalizations?
Have you ever done banking in Japan?
> Even if I'm using this "immediate payment system", I'm pretty sure my local bank will still delay my payment by a few days "because they are used to do it that way".
You realize there are EU directives behind the standards implemented by banks? SCT Inst has to be operated 24/7, and transfers available at the receiving end within 10 seconds.
well it seems SEPA didnt take too long to implement, and frankly most banks have gotten used to frequent changes in EU banks regulation so, if this is real, it might not take too long
The proof of ownership system described above is a blockchain where every single block is produced at irregular timestamp and contain a single transaction.
That talk was inspirational, as was the follow up ~10 years in progress video that came up next. I'm going to give FreedomBox a try. It is sad that I've never heard of this until now.
Used to get Saharan dust in Puerto Rico (when I lived there). Thin layer of black dust throughout the apartment that had to be cleaned every 4 days or so.
I know Saharan dust does reach Puerto Rico but after looking up the soot theory, it seems more plausible. I even found two local articles in Spanish about it (soot).
