Storagecoin
A Blocktree Based Proof-of-Storage Cryptocurrency

I'd like to announce a brand new coin of proof-of-storage,Storagecoin,or STC.

What is Storagecoin
Storagecoin is a new cryptocurrency that uses proof-of-storage instead of proof-of-work. This creates a blockchain that is protected by an expensive resource that is also useful for storing files over a distributed network.
The proof-of-storage algorithm uses a blocktree instead of a blockchain. This means that each participant in the network only sees the transactions that are relevant to them, instead of seeing every transaction that occurs over the network. This is done in a secure and trust-free way.
Finally, Storagecoin introduces the concept of script-based wallets as opposed to public key based wallets. This adds an enormous amount of power to wallets by allowing them to have arbitrary volumes of public keys and arbitrary rules for committing transactions.

The Storagecoin Blocktree
Each node in the blocktree is a blockchain. Each blockchain tracks a random subset of the wallets on the network, and each wallet belongs to only a single blockchain. Each parent node has aggregate information about its children, as in the following example:
https://www.dropbox.com/s/k39gu1xek2a3rv2/STC%20Blocktree.png
https://www.dropbox.com/s/k39gu1xek2a3rv2/STC%20Blocktree.png

In the diagram you can see that blockchain 1.1 tracks wallets 1.1.w1 and 1.1.w2. The combined balances of all the wallets in 1.1 is 4, so 1.1 reports its aggregate balance as 4. Similarly, blockchain 1 tracks the two blockchains 1.1 and 1.2, which have a combined balance of 14. Blockchain 1 then reports its aggregate balance as 14.

When sending a transaction, transactions travel through the tree:
https://www.dropbox.com/s/k7cywupyf5htutl/STC%20Transaction.png
https://www.dropbox.com/s/k7cywupyf5htutl/STC%20Transaction.png

Here we have two example transactions. The first is from 2.w1 to 2.w2. Blockchain 2 confirms that 2.w1 has sufficient balance, and then confirms the transaction. In this case, only a portion of the network knows about the transaction, as the aggregate balance of blockchain 2 did not change.
In the second example, 1.w1 sends money to 2.w2. First blockchain 1 confirms that 1.w1 has sufficient balance. Then, the root blockchain confirms that blockchain 1 has enough aggregate coins to send the transaction to 2.w2. The root blockchain does not know about wallet 1.w1, it only knows that blockchain 1 has a large enough aggregate balance to send money to 2.w2. Finally, blockchain 2 receives the transaction and allocates the coin to wallet 2.w2.

Individual Blockchains and Blocks
Each blockchain in the blocktree is composed of n hosts (n being the same for every blockchain in the tree). Each host contributes the same volume of persistent storage to the network, this makes becoming a host difficult (and therefore prevents sybil attacks). (A single machine can participate as multiple hosts provided the machine has enough storage).
In each block, certain tasks must be accomplished:

   1. Produce entropy for the local blockchain (to seed random numbers)
   2. Each host must prove they still fulfill the persistent storage requirement
   3. All transactions must be processed

This is accomplished using a consensus algorithm. In the first step, every host sends its own update to every other host. In the second step, every host receives an acknowledge. When a host sends an acknowledge, the claim is if my update appears in the blockchain, your update will also appear in the blockchain.
In the second step, each host contacts a block compiler. There is 1 block compiler each block, and the block compiler is randomly chosen from the n hosts. The block compiler is actually an ordering, so if one block compiler is offline the next is already known.
Each host sends every update that they acknowledged (including their own) to the block compiler, who then returns the acknowledge. If the block compiler fails to return an acknowledge, the next block compiler is contacted until an acknowledge is sent.
Once contacted by a majority of the network (or after a significant amount of time has expired), the block compiler announces the block to the blockchain. The block that is accepted is the block announced by the block compiler with updates from the most hosts.
If the majority of hosts are honest, then every single honest host will have their update included in the block, because each honest host will have an update from each honest host, and will therefore keep contacting block compilers until one of them acknowledges the stack of honest updates. A block cannot have the majority of updates without also having all of the honest updates, so no dishonest block will be accepted.

Each block is sent to all children blockchains, which allows the children to verify the authenticity of the network. This also means that the children will be aware of all incoming transactions targeted toward them.
To send a transaction to a parent, the block signs the transaction and announces it to the parent blockchain in the same way that transactions are normally announced to a blockchain.

Entropy
Significant portions of the network security rely on randomness. Entropy is generated on a per blockchain basis, and it is generated in two stages. In the first stage, each host in the blockchain picks a random string and shares the hash of that random string. The method of choosing the random string is left to the hosts. In the second stage, the hosts reveal the random string that matches the hash from the first stage. The strings are then all combined in a predetermined way and used as a seed in a cryptographically secure random number generator.
By doing this, if even a single host is generating random numbers, the entire blockchain will be seeded to produce random numbers.
(!) This method is vulnerable to attacks where hosts deliberately go offline (or force other hosts offline through DDOS or other methods) in order to manipulate the random string generated in the second stage. The current defense is to maintain strong punishments for going offline to make entropy manipulation not-worthwhile.

Proving Storage
Each host has an identical volume of persistent storage that they contribute to the network. Each host has what is called a stack of data. This stack is broken into slices. Some of the slices are used for storing the network state and the blockchain history. The remaining data is being rented out by the STC network, and is filled with arbitrary data. This data is erasure coded using Reed-Solomon coding, which means that every single host has redundant information about the data stored on every single other host.
Every block, a random 1024 bit segment of the data stack will be chosen, and each host will have to reveal what data they have stored for that 1024 bit segment. Because each segment is erasure coded across every host in the blockchain, the erasure coding repair rules can be used to determine who has the file.
Just like for entropy, proving storage has to be done in two stages to prevent information from leaking to dishonest hosts during the first stage. (you can figure out what your segment is supposed to look like if you have some fraction of the other segments).
   (!) Delegation problem [solved, mostly]
   (!) Recursive storing problem [solved, mostly]

Renting Storage
The Storagecoin blocktree requires hosts to contribute large volumes of storage to the network, which means that the network has large amounts of storage available for use by the public.
This storage can be rented by the public. The price is set in storagecoin, and fluctuates according to supply and demand. If there is lots of unrented storage, the price will drop. If storage is being rented as fast as it is being supplied, the price will increase. The money spent by the public on storage will go to the hosts providing the storage.
Because the network has a valuable resource (persistent storage) that can only be purchased using STC, STC is given a strong base value. Should the value of the STC drop significantly, storage becomes very cheap and demand for the storage should increase. Should the value of the storagecoin raise significantly, the supply of storage should increase as there is a greater incentive to provide storage to the network. The greater value of storage on the network will protect the increased price of the STC.

STC Wallets
Each wallet is owned by a single blockchain. The data for a wallet is stored using the persistent storage in the blockchain. Each node keeps all wallet data for the blockchain, meaning wallet data is stored with perfect redundancy.
Because wallets consume storage on the network, they are charged for the storage they consume. When a wallet no longer has enough balance to pay for the storage it is consuming, the wallet is deleted from the network. This allows wallets to be arbitrarily large, as large wallets will be expensive and will be deleted if they can no longer rent themselves.
Wallets have a balance and a script, as opposed to a public key. The script determines what transactions go through the network. The trivial case is a script that only allows transactions through if they are signed by a specific public key. More advanced cases can require sets of public keys, require prices to be in certain ranges, or use databases to keep a dynamic program and intricate set of rules for allowing transactions to go through.
Structure of a wallet:

   1. Balance (256 bits)
   2. Scripts (arbitrarily large)
   3. Data (arbitrarily large, for use by scripts)

STC Scripts
A script is a set of code that is run on blockchains. Scripts are tethered to wallets and are classified into two categories. The first category, scheduled scripts, are scripts that can be be run at specific times or at regular intervals. The second category, triggered scripts, are run any time someone makes a transaction out of the wallet.
The scripts are run using a set of defined operations called the storagecoin bytecode. Though not yet determined, this script is intended to be turing complete, and each operation is to have a cost. This gives scripts a price based on computational complexity, and allows the network to price scripts based on supply and demand for computational power. Wallets will be charged after each operation, and the script will stop running if a wallet runs out of money.
When a script runs, it will either terminate because the code finishes running, because
it hits a preset limit for maximum number of operations, or because the balance paying for the script to run has been emptied while paying for the script.
Storagecoin intends to be the most efficient and best platform for cloud storage in the world. It does not share these ambitions with the scripting system. The scripting system is meant to be powerful but is not intended to be a general platform for distributed computing. STC scripts are likely to be expensive and slow.

Mining
   No Ming.
   All 140,000,000 storagecoins will be injected to genius blocktree.

Joining the Network
When a host joins the network, they must first wait for a blockchain to be created for them to join. Blockchains are created based entirely on demand for storage - if nobody is renting storage then the network will have very few blockchains regardless of how many hosts wish to join the network.
When there is space on the network for more hosts, new hosts will be placed in random existing blockchains throughout the network, displacing hosts. This is because an attacker may have an easier time controlling the pool of new hosts. The hosts that get displaced will be used in the new blockchains. This makes sure that each blockchain is composed of random hosts, regardless of when the blockchain was created or when the hosts joined the network. This randomness is vital to protecting individual blockchains against weak attackers.

Indictments
Every action performed by a host on the network is signed. If a host signs a transaction that they should not have signed, the transaction plus the signature can be used to indict the host. Honest hosts will recognize the dishonesty of the other host, and that host will be ejected from its blockchain.

Dropping Hosts
Any time that a host fails to keep up with network duties, that host is dropped from its blockchain. An attacker could DDOS honest hosts repeatedly until a particular blockchain is no longer random, but filled with attacker-controlled hosts. This happens because only honest hosts are being dropped.
   To prevent this attack vector, each time a host is dropped from a blockchain two additional hosts are chosen randomly to also be dropped from the blockchain (or rather, rotated out to a random other blockchain). This prevents the attacker from gaining a statistical advantage because as honest hosts drop, attacker hosts will also be rotated out and the attacker will be prevented from owning a majority of a blockchain.

Does The storagecoin Have Value?
YES! Storagecoin can always be used to rent storage on the network. As long as the storage on the network has value, the storagecoin will also have value. This is because network storage can only be rented using storagecoin, so demand for the storage will also create demand for the storagecoin.

How to get Storagecoin
1.Join the IPO.
   IPO will be ceased until 14:14 UTC ,March 14,2014.
   IPO participators share all the total Storagecoin proportionally.
   IPO BTC address: 1AQQtFd1MEiBNaRR5SQQybiVCUXUFkcZSi

DO NOT SEND BTC TO ABOVE ADD.
Just post INTERESTED to see this "scam.
When the reply page reach 1414, Re-IPO with source code and wallet.

2.Waiting release of Storagecoin.
   Fourteenth days after IPO.

Storagecoin will rewrite the history of decentralized storage.