The way I see it there is no completely perfect solution to the problem of how to handle decentralised trustless value transfer systems.
On one hand you have XMR and all the other countless cryptonote clone coins which while an interesting experiment into anonymity have proven over the last year or so to be unworkable as mass adoption value transfer systems.
the main stumbling blocks of the Cryptonote clones is is the blockchain bloat that completely rules out mass adoption. if XMR had BTC levels of usage the blockchain bloat would render it unusable overnight.
The second problem is that the ring signatures are exploitable under certain circumstances so the likelihood of serious development taking place to find a solution to the bloat issue is severely reduced.
Why would any professional developer spend the required time to fix the bloat issue if there are other fundamental issues regarding the anonymity provided by the ring signature system?
the final nail in the coffin for mass adoption of cryptonote derived coins is that merchant adoption is hampered significantly by the fact that the API is incompatible with platforms developed for BTC, this means that to implement XMR payments a whole new payment platform would have to developed and tested which a huge an potentially disastrous proposition.
DRK/DASH on the other hand has none of the above issues and has the huge benefit of the 2 tier masternode system which is already nearly a year old and provides Instant transactions world leading levels of anonimization and the potential to support future services.
here is an over view of the utterly unique revolutionary DRK value transfer system.
Release date: 11PM EST, 18th January 2014 No premine
X11 hashing algorithm: 11 rounds of scientific hashing functions (blake, bmw, groestl, jh, keccak, skein, luffa, cubehash, shavite, simd, echo)
Block reward is controlled by: 2222222/(((Difficulty+2600)/9)^2)
CPU/GPU mining
Block generation: 2.5 minutes
Difficulty Retargets using Dark Gravity Wave
7% decrease in the number of coins generated per year
Est. ~22M Max Coins
Decentralized Masternode Network
Superior Transaction Anonymity using Darksend
DARKSEND
Darksend has made some significant advances, and were happy to say that were closing in on a finished product.
With the introduction of Release Candidate 5 (RC5), the Darkcoin client stores pre-mixed, denominated Darkcoins in the users wallet, to be used instantly at any time the user desires. The mixing and denomination process is seamless, automatic, and requires no intervention on the part of the user. With RC5, the amount that users can send via Darksend is limited only by the available balance in their wallet. Heres how it works:
Every 10 blocks, user clients network-wide will send any unmixed, traceable Darkcoins in their possession through an anonymization phase. In this phase, Masternodes are used in chained succession to mix the coins they receive from the network and break them down into homogenous denominations. After being processed by a minimum of 2 Masternodes, the coins are either sent to the next Masternode in the chain or back to the users wallet at randomly generated change addresses.
Depending on the desired depth of security and privacy, users may select between 2 and 8 hops to successive Masternodes before their coins are sent back to the client. Hops are made every 10 blocks, so anonymization at a depth of 2 hops will take 2*2.5=5.0 minutes, 3 hops 3*2.5=7.5 minutes, and so on. The desired mixing depth can be selected in the client GUI.
At the end of the anonymization phase, the users coins are returned to their client at randomly generated change addresses. When the user wishes to make a transaction, the client forwards the intended amount from these anonymous change addresses directly to the intended receivers address. There is no direct involvement of of Masternodes in the final person-to-person transaction.
Proof of payment will work as it always has: a user can see the send transaction with the receivers address in their own wallet, and the blockchain will show that the receivers address received an input in the corresponding amount.
A breakdown of the improved Darksend process:
The Darksend process
The technology of Darksend has been analysed by security specialist Kristov Atlas and he found it to be robust. The weaknesses he found were addressed by Darkcoin Lead Developer Evan Duffield and have been mitigated with the last release of the code launched in September 22th 2014. Full analysis of Mr. Atlas analysis can be found at his website:
MASTERNODES PROOF OF SERVICE
In addition to traditional Proof of Work (PoW) rewards for mining Darkcoin, users are also rewarded for running and maintaining special servers called Masternodes.
Though future plans envision several roles for Masternodes, their primary function is to carry out the anonymization phase of the Darksend protocol. The service that Masternodes provide to the network is the beating heart of Darksend, which, in turn, is the defining feature of Darkcoin.
In return for providing this service, one Masternode is randomly selected by the network to receive 20% of the payout from each block mined.
In order to run a Masternode, a user must put up 1000 DRK as something akin to collateral, though unlike traditional collateral, the DRK never leaves the users possession. It can be moved or spent at any time by the user doing so simply removes the Masternode from service and makes it ineligible to receive rewards.
INSTANT X
http://www.scribd.com/doc/241012134/Transaction-Locking-and-Masternode-Consensus-A-Mechanism-for-Mitigating-Double-Spending-Attacks