Dash (crypto currency)
Dash (formerly known as Darkcoin and XCoin) is an open decentralized payment system in the form of a block-based crypto currency, using the mechanism of anonymous transactions .
Like most crypto-currencies, DASH does not have centralized control - the issue occurs when mining. From the reward received by the miners, 90% are distributed between the miners and the operators of master classes. The remaining 10% are used to finance approved projects  .
As of the end of 2017, Dash for capitalization is among the top ten popular currencies .
The main differences between Dash and Bitcoin are as follows:
Transactions in Dash are anonymous 
Dash uses not one, but a combination of several cryptographic algorithms 
Mining Dash requires less energy 
Decisions on the further development of the system are made not by individual programmers, but by all members of the Dash network through the mechanism of decentralized governance (Decentralized Governance)   
In addition to the mining mechanism, Dash uses master codes , which provides both faster transaction confirmation and anonymization procedure.
"PrivateSend" is a payment-mixing service based on CoinJoin. Subsequently, the pre-mixing method was improved and built into the client program.
The current implementation of the system allows you to increase the anonymity of transactions by combining multiple inputs from different users in a single transaction with multiple outputs. This hides the flow of funds and limits the ability to directly track transactions. To monitor such transactions, a mechanism was proposed for a hierarchical list (based on entrances and exits), however, there was no practical evidence for the possibility of such an analysis. 
The PrivateSend mechanism includes a number of procedures:
Preliminary denomination - payments are split into equal parts: 100, 10, 1, 0.1, which prevents tracking by individual amounts.
Each part goes through its own stages of anonymization, while
not the entire amount is anonymized, but parts
Mix exclusively coinciding parts of the volume
at each stage a new mixing master is selected.
Stirring takes place in advance. After mixing, the amount is returned to the owner for new anonymous addresses and can be used when required (no need to expect mixing).
As the number of users increases, DASH becomes more difficult to get rid of the uncertainty in the blending structures.
Masternodes (Masternodes) are special nodes (servers) of the network that provide the work of the "PrivateSend" mixing mechanism. Masternodes are managed by a community of volunteers without a single centralized governing body. Every time the user intends to use "PrivateSend", he indicates the number of rounds of stirring (usually two to eight, but can be more), which significantly increases the degree of anonymity. Next, the randomly selected Masternodes intermix coins. The combination of several random independent master programs increases the confidence that no one has complete information about all inputs and outputs in the transaction process.
To avoid a scenario in which a number of Master-Dods on the network are managed by an attacker who wants to uncover anonymous transactions, a deterrent is applied: for each Masterdnode connected to the network, a pledge of 1000 Dash is required.  In order to encourage volunteers to create and manage master crafts, they are entitled to a reward of 50% of the reward of the miner for the block found. 
"InstantSend" is a service for instant transactions. In this system, the inputs are blocked only for a particular transaction that is verified by the consensus mechanism in the Masterdn network. Conflicting transactions are blocked and rejected. If a consensus can not be reached, the confirmation of the transaction occurs using the standard block confirmation mechanism. InstantX allows you to solve the problem of double spending without long waiting for confirmation, as is the case with other crypto-currencies such as Bitcoin. 
Instead of using the SHA-256 algorithm (from the Secure Hash Algorithm family) or scrypt, in Dash 11 different hashing functions are consistently applied to prove the work performance. 
X11 is a system of hashing algorithms that uses a chain of 11 algorithms such as a cryptographic hash function to prove the performance of the work. Algorithm X11 was proposed by the main developer of the Dash system Evan Duffield (Evan Duffield) in order to complicate the use of specialized equipment for mining.
For sequential hashing, last generation CPUs on average produce the same performance as the GPU. When running such an algorithm on GPUs, approximately 30% less electrical power is required, compared to the
scrypt algorithm and 30% to 50% less heat removal resources. This can significantly reduce the costs of the miners and extend the resources of computer equipment. 
Dark Gravity Wave (DGW)
Dark Gravity Wave (DGW) - an algorithm for adjusting the complexity of mining, created to circumvent the shortcomings in the algorithm Kimoto's Gravity Well. In this case, a multiple and simple moving average is used to smoothly adjust complexity, which is recalculated for each block. The reward for the block does not change strictly with the block number, but instead uses a formula based on Moore's law: 2222222 / ((Difficulty + 2600) / 9) 2.