At best, they send you money..
MD5: 128bit. 2^128. 3.40282366920938463463374607431768211456 Ã-- 10^38 combinations
SHA1: 160 bits. 2^160. 1.461501637330902918203684832716283019655932542976 Ã-- 10^48 combinations
SHA-256: 256 bits. 2^256. 1.1579208923731619542357098500868790785326998466564056403... Ã-- 10^77 combinations.
SHA-512: 512 bits. 2^512. 1.340780792994259709957402499820584612747936582059239337... Ã-- 10^154 combinations.
Big numbers. Comparison numbers:
estimated number of atoms in the Earth: 1Ã--10^50 atoms
estimated number of atoms in the Milky Way galaxy: 2.9Ã--10^76 atoms
estimated number of atoms in the universe: 1Ã--10^80 atoms
The chance of a random hash collision, even factoring in birthday attack, is extremely small. It's also not a problem, even if it happens. As it is paired with a login name, you don't suddenly have person A logging in as person B.
And as noted, the length of a hash is fixed for the algorithm.
As someone who hasn't written such a scalable app, but have been interested in the issues around it, this was more or less my first thought too.
App part is usually just "throw hardware at it", but DB part can be really hairy. You can get far on a one machine DB, but once you need to go past that, you got trouble. Unless you've already taken that into consideration.
Also, it's good to be familiar with the common problems and workarounds for scaling. Caching is one such thing. Often you got several possible ways to do things, and some of them lends themselves better to scaling than others. Often with little or no extra work. Or it's just a small tweak to functionality, hardly noticeable that's needed. But something that will be a royal PITA to change later on.
So my advice: Get familiar with scaling problems and solutions, keep them at the back of your mind when creating the site, but don't go out of your way. Not yet, at least. Maybe take time to make easy "hook" areas in the code where you can insert scalability later (f.x design things so it's easy to move parts of it to RPC later on, and make it easy to later add caching to areas).
I'd just like to point out that gold have had the same characteristic, in the beginning it's easy to mine/wash/find, but as time goes it's getting harder and harder as all the easy spots are cleared out. And it's only economical to mine those harder spots out because the value of gold have risen.
Would you say gold is a pyramid scheme, because it was easier in the beginning? Bitcoin is in many ways digital gold, where the rarity comes from the resources it takes to "extract" bitcoins. Gold itself is not currency, but can be bought and sold. And also have fluctuations in value.
Personally I think bitcoin will be doomed in the long run, since there's a max limit to amount of coins, and coins will slowly fall out of the system (if the cryptographic wallet key is lost, all coins in that walled will be unable to be moved to a new address - and with time and Murphy's law, more and more coins will be rendered inactive).
but for now there is no scarcity at all.
Then why don't you just drum up a few hundred thousand bitcoins and sell them? You'll be bloody rich, AND you will have the pleasure of crashing BitCoin market and show everyone how right you are and how wrong they were.
Currently, 25 bitcoins are generated every 10 minutes. This will be halved to 12.5 BTC within the year 2017 and halved continuously every 4 years after until a hard-limit of 21 million bitcoins is reached within the year 2140.
To compensate for increasing hardware speed and varying interest in running nodes over time, the proof-of-work difficulty is determined by a moving average targeting an average number of blocks per hour. If they're generated too fast, the difficulty increases.
So the supply is rather fixed globally. If the demand is higher than the supply, there will be scarcity, and prices will rise. They might bounce up and down while the market adjusts, but as long as the demand is higher the average price will rise, until it's high enough that the demand is at the same level as the supply.
But it does hold more data than your "It's so unsafe it will fall down and break horribly any moment now" statement
Anyway, it's a habit, and my personal experience tells me it's far less of a problem than your guessing says it should be.
You shouldn't hold your breath, I've had this phone since November, and I still haven't lost it while holding it that way.
Maybe I'm just not as clumsy as other people, but hey, no one is judging.
I got the Note 2 and I can use it one handed just fine.
But, your test is actually invalid, because it makes wrong assumptions.
with the tips of your fingers holding the far edge
That's not needed, finger tips just needs to be beyond the balance point at the middle of the back. Combine that with resting the phone edge to theflat of the hand, and you actually got a pretty decent grip.
That's funny. You know why? Because here in Norway you can't use USD to pay for anything except amongst a tiny group of people.
Not unless you convert them into real money first. I guess this shows that USD is just a toy currency and will never amount to anything in it's life.
No no no.
Step 1: Connect it to an old computer
Step 2: Install squid
Step 3: Time to stock up on certain
There's the same rules in Norway. And providers almost never allow repeaters / boosters.
There was a case some years ago where someone set up such a repeater illegally, managed to cause a feedback loop with some cell towers, thus knocking half the town off the grid.
It starts, with a killer asteroid hurling towards the earth.
Our hero is summoned, and immediately springs into action.
He sets out with his trusty weapon to save the world from the danger of the week.
Finally there, he slowly takes aim, breathes, and fire at The Killer Meteor. The meteor, alerted to his presence, fights back. What follows is a long action sequence only slowing down now and then so our hero can do manly poses.
After a long battle, and lots of shooting and fishing was done, there was only a small fragment left, just enough to spend the CGI budget, and show everyone how dangerous The Killer Meteor could have been.
No one was killed, and the world was again saved thanks to our hero.
Linux-Friendly* Mini** PC Fast Enough*** For Steam Games****
* Just like every other PC
*** Slow as heck
**** Completely unusable for Steam games
Could anyone break the Crackberry monopoly? Well yes, iPhone could, and quite spectacularly too.
Could anyone break the Symbian phone system, with all its apps? Yep, iPhone again.
Could anyone break the iPhone monopoly? Yes, Android did that.
You can't judge the future just by what is now, folks. People have tried that before:
"This 'telephone' has too many shortcomings to be seriously considered as a means of communication."
-- William Orton, president of Western Union, in 1876, when Alexander Graham Bell tried to sell the company his invention.
"There is no reason anyone would want a computer in their home."
-- Ken Olsen, founder of Digital Equipment, in 1977.