U asked for critique so here it is: the coins makes no sense what so ever. Whats the point of low confirmation if block can be invalidates later? There is so much more that is so wrong. Please study definition of money before deciding on protocol. I like the name though.
From your statement it sounds like you're thinking that this is an alt chain somehow based on the same principles as bitcoin, with minor tweaking.
It's not.
To address your statement that I should learn the definition of money. I have studied the definition of money, in fact I have a degree in it. Not to get into with you, but I have a masters degree in finance and a bachelors in computer science and over a decade working in IT primarily with banks and finance companies. I only mention this fact so that you can see where I'm coming from is a perspective of experience, not just something someone once told me.
I realize you've probably read Satoshi's papers and probably a lot of other things off the internet.
You should be aware that there is a lot of errant information out there, mostly due to misunderstandings about how money works vs what money is.
The average person knows what a car is. They see a car and probably know how to operate one. But few people actually know how a car works.
The same thing can be said of money. You look at the cash and cards in your wallet and you assume they are money. You assume you know where they came from, how to use them and hopefully how to get more when you need them. However it is doubtful that you really understand how money works at a fundamental level. What units are being moved around in what quantities and why. Do you know exactly where that 5 spot in your wallet originated from, and who handled it for what reasons up until the time you placed it in your wallet? Probably not. Neither do I, but the point is money is only part of an economic system, however it is a vital part of one and as I said before it is part of a living, breathing, chaotic, dynamic system. Expresscoin is designed to enable commerce by being able to enable the same types of transactions where you would use other currencies and financial instruments. At the same time it is designed to allow people of limited means to support themselves while preventing the types of dynastic wealth accumulation that have ruined other financial systems.
Even though your post is a bit terse, I can see that you are looking at it from too narrow of a view point.
You appear to see ExpressCoin as another altchain built on bitcoin rules with minor modifications. You would be wrong.
The reason for this coin is that I believe bitcoin and other altcoins have certain things right and other things wrong.
Before you can understand all of that, you need to look at what money actually is.
Money is anything that is commonly accepted in an exchange of goods or services.
Currency is just a type of money that is specialized to a particular market.
All currency is money, not all money is currency.
Everyone will accept money, but not everyone will accept any particular currency.
Just try spending a Euro at a place that takes dollars or vice versa for an example of what I'm talking about.
The value of a currency is nothing more than a reflection of the confidence of the people who accept it, have in the originator of the currency.
This is why you can't go into a grocery store and buy a gallon of milk with a silver ingot. The merchant doesn't know if the ingot is real and wouldn't know the exchange rate of silver to gallons of milk even if they could prove it's real, i.e. the merchant has no confidence in your silver ingot.
But if you go into the store with an actual silver dollar, you can use two or three of them to buy your milk.
Now a silver dollar weighing 1 once with 99% purity has a melt value of $24 in todays prices.
A silver eagle dollar bought from the US mint would cost you $48 today.
You just traded 2 or 3 of them for a gallon of milk, that's about $150 for a gallon.
Nevertheless, the merchant isn't actually accepting your silver.
They are accepting the marks on the coin.
These marks say that the full faith and credit of the US government in that ounce of silver amounts to exactly $1.
This is why your dollar can be made of silver, paper, base metal, or 1's and 0's in bank account somewhere.
The merchant's faith and your faith have now amounted to saying that this gallon of milk has cost you $3 regardless of how much money those dollars cost you to obtain.
Bitcoin's design exhibits a lack of faith and trust.
This is an intentional design feature.
It doesn't need trust or faith because everyone has full access to the complete history of any bitcoin and can verify that the coin has 3 properties.
First that the coin actually existed prior to being spent, second that it's "not stolen" (not stolen being defined as a signature signing it over), third that it's not counterfeit (double spent).
This comes at a cost. Some of the cost is imposed by the network and some of it is imposed by the design of the currency.
The primary cost is in the size of the block chain.
It will continue to grow forever because it will need to be readily available for each and every transaction to be fully verified.
The second cost is in the time it takes to confirm a transaction.
Bitcoin uses artificial scarcity to enforce a very slow block generation rate. It does this through it's difficulty level which is adjusted every few weeks.
On it's surface this is ok, because ensures that there is a specific, planned amount of money in the system.
However it's bad for the kinds of commerce that require instantaneous confirmation.
The third is in what a transaction confirmation actually means.
In bitcoin it means the 3 things I've stated above.
First that the coins existed prior to being spent, second that it's not stolen and third that it's not counterfeit.
The fourth problem is one of the actual money supply or more accurately the currency supply.
Bitcoin states that only 21M bitcoins will EVER be mined. After which transaction fees will account for most of the income of miners.
Unfortunately 21M anything is not enough currency to support any economy. Even if you infinitely divide it, if you have to know the complete history of a coin it will take longer and longer to verify.
This means that as time goes on, the power behind the currency will consolidate into fewer and fewer hands.
This is because the computing power needed to verify a trasaction grows with the total number of transactions in the system.
Just as with mining now, hashing power is being consolidated and it will become only a few large players that make the majority of the bitcoins.
That is not a desirable feature of a democratic currency.
In addition, because there are so few bitcoins ever and because coins once lost can never be replaced, the overall economy will rarely be deflationary, only hyper deflationary.
This "coin attrition" also means that there is no way to distinguish what is being hoarded vs what is being lost.
This lack of information in the system makes it very speculative and is one reason that prices will continue to fluctuate outside the realm of what anyone other than speculators feel comfortable with.
Some people will say that these are all good things for a currency and for the right type of person this is probably correct.
Other's will say that the underlaying problem here, "price instability" is a good thing because it is the result of a free market.
These people are conflating a free market with an ignorant market.
Both free and ignorant markets lack any sort of significant price controls.
A free market can only exists when everyone has access to the same information (this is why insider trading is considered a crime btw).
If a major portion of the market cannot access information about it but still participates in it then you no longer have a free market, just an ignorant one.
ExpressCoin doesn't style itself as something for investors or speculators. Speculators aren't needed because it's intended to be highly liquid by design.
ExpressCoin is designed for the needs of daily commerce, or in otherwords it is designed to fuel an actual economy.
For instance the act of waiting on confirmations. This drastically slows down commerce. The only practical purpose it serves is to avoid doublespends.
Statistically speaking, even now with bitcoin, for a transaction to be considered final , it just needs to be included in a block by a miner.
That means on average it is 10 minutes before you "know for sure" it went through and even then it could be a day.
The problem is that even though most people are not criminals or out to defraud anyone, the bitcoin network treats every transaction with suspicion.
With ExpressCoin, ALL tranactions are assumed to be valid unless PROVEN otherwise. When a transaction IS proven as invalid, the risk passes solely to the miner.
The merchant bears no risk. The merchant will always get his money, thus he has confidence in the system.
Another key difference is how far back we go to validate a transaction.
With bitcoin you have to go back to the genesis block.
With ExpressCoin we only go back a max of 1 year.
Under ExpressCoin we state that a valid transaction consists of
#1 A list of input transactions.
#2 That all inputs have the requisite m of n signatures.
#3 That no inputs are already spent.
However what it really does is transfer the risk of a bad transaction occuring off from the merchant and onto the miner.
Because the miner is accepting this risk, and is in effect "backing the transaction", the turn around time on a transaction can be measured in milliseconds on average and a few seconds at most.
In accepting this limited risk, the miner is rewarded far in excess of what the risk actually would be.
Since the primary people who might attack the currency would be miners themselves (trying to get invalid blocks to be accepted), it makes the most sense to transfer the risk to them.
This risk transference is done by way of the bond system I mentioned earlier, but here is a shorter version.
A miner recieves a transaction and adds it to a block. He computes the hashes and declares a block.
When he declares a block, he must place an amount in escrow equal to the amount of coins that the block contains.
If after 24 hours the network still views the block as valid then those funds now belong to the miner.
If there is a problem with the block, it is unwound, the errant portion removed and the block is rehashed.
This must happen for all blocks which derive from that block and of course it is disruptive to the network.
Because of the disruption caused by a teardown and rebuild, the miner must pay a penalty.
However there is no reason why the merchant should have to wait, nor the consumer.
As long as the miner is performing the minimal verification we've mentioned above though, this should never happen. it would only be invoked against a misbehaving miner.
In fact the estimate is that if we are creating a billion transactions per day, that this would happen less than once a week and should disrupt the network for no more than 5 minutes.
That's all really heady stuff so let's say that ExpressCoin's motto is...
Money should enable commerce, not get in the way of it.
