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The Trustchain Consensus

COTI: An end-to-end platform that offers a full solution to create the payment networks of the future.

The newest version of COTI’s whitepaper is now available on our website, and it’s the perfect time to get an explanation from COTI CTO Dr. Nir Haloani about the innovative Trustchain consensus algorithm and Arbitration System.

For cryptocurrencies to change the face of the payments landscape and replace fiat money, they need to be highly usable and convenient. One of the most important shortcomings of all existent cryptocurrencies is lack of volume, speed and scalability. Several blockchain based technologies have been created to tackle the challenges posed by attempting to provide high transaction throughput while remaining inexpensive, but these have been met with little success. Another challenge faced is the lack of trust between unknown parties, which leads to countless chargebacks and transaction cancellations. Moreover, merchants are often classified as ‘high-risk’ or ‘low-risk’ based on their association with a particular industry, rather than on their actual behavior.

COTI, Currency Of The Internet, solves these challenges by using an innovative base-layer protocol in the form of a directed acyclic graph (DAG) ledger, built from transactions connected through time by harnessing trust-based algorithms. Trust is based on a combination of the network participants’ historical behavior data and objective information about them. COTI takes this into consideration when calculating Trust Scores using a unique machine-learning algorithm. Trust is used in the Trustchain Algorithm to validate and confirm transactions faster. Trustchains grow as new transactions attach to two prior transactions which have similar degrees of trust as themselves. This results in an innovative consensus-based confirmation mechanism, where every user is incentivised to engage in trust-building behavior due to the benefits associated with having a high level of trust (i.e. faster confirmation times).

COTI has built mechanisms to monitor, detect and defend against possible attacks to ensure network security. An example of such a mechanism is COTI’s Double Spend Prevention (DSP) Nodes. COTI has also introduced novel protocols to address disputes that may arise when sending transactions, a highly required feature which is not possible with other cryptocurrencies.

Dispute resolution is achieved through the use of an Arbitration Service. This service takes advantage of the principles of game theory to ensure a fair outcome in the case of a dispute and votes to determine which of the two disputing parties is right.

The Base Layer Protocol

DAG-based distributed ledger technologies show signs of being particularly adept at overcoming the scalability limitations inherent in blockchain-based payment networks. While in blockchain-based networks, greater scale has undesirable effects on network usability, in DAG-based networks the reverse is generally true: greater network usage results in improved network scalability. In other words, there is a positive correlation between the number of network users and the rate at which transactions are confirmed.

As a result of the positive correlation between network usage and network scalability, the DAG data structure is ideally suited for the COTI network’s base layer protocol, and will enable it to achieve full decentralisation without compromising COTI’s commitment to scalability, instantaneity and low (or zero) fees. Building on the foundations established by the above-mentioned initiatives, COTI is introducing an innovative DAG-based distributed ledger technology as its base layer protocol, which involves the use of Trust Scores as the key mechanism by which new, unconfirmed transactions select prior transactions to validate. Furthermore, COTI’s DAG-based distributed ledger technology, the Cluster, reaches faster consensus when confirming transactions by using COTI’s Trustchain Algorithm. Eventually, the Cluster will be able to validate and confirm a maximum of hundreds of thousands transactions per second (TPS).

Actors in the COTI network possess their own Trust Score metrics, including Nodes. A Node’s Trust Score, however, is not the same as a Node owner’s Trust Score.

All accounts in the payment network have a Trust Score, which is changed according to a user’s payment statistics and several event types. An account Trust Score is a real number within the range [0,100]. All transactions in the payment network also have a Trust Score. The Trust Score of a transaction is the sender’s Trust Score when the transaction is initiated. The Cumulative Trust Score of transaction A is the sum of all the Trust Scores of all transactions along the heaviest path approving transaction A, including transaction A itself.

The Trust Score Algorithm is designed to ensure the maximal performance of the Trust Score-based Source Selection Algorithm. For example, let the recommended level of trust (cumulative Trust Score) for the transaction be 1000. This means that transactions created by highly trusted network participants (TS~85) need at least 12 confirming transactions in the chain, while transactions from low trusted network participants (TS~12) need at least 84 confirming transactions in the chain.

Trust Score Nodes collect transaction and other statistics to continuously update participants’ Trust Scores as described in the Trust Score Update Algorithm subsection below.


The COTI network uses a transparent and equitable fee model . All fees are paid in COTI coins and are collected by Full Nodes which are decentralised servers run by ordinary users in the COTI network. The COTI network receives a portion of fees collected by Full Nodes to support infrastructural technology, such as the Double Spend Prevention Nodes and Trust Score Servers. When the network is first created, a portion of all generated COTIs will be set aside as a Reserve Fund to pay for all transactions until the network matures. Therefore, the network fee will be set to zero during the network’s infancy. Following this period, the fees will be minor due to the decentralised nature of the network. During the steady-state operation of the network, positive behaviour is incentivised by offering lower fees for network participants with higher trust scores.

Each Node charges a fee that is in part determined by the Node itself. Some Nodes may set a higher fee if they believe they provide a good service; other Nodes may charge less or possibly nothing. The price charged by a Node for its services should be equitable, publicly available and compliant with common network rules. Network rules will define a ceiling for fees, but there will be no minimum fee.

It is possible for merchants to run their own Full Node along with a customised wallet if they think it will provide a better experience for their customers.

Closing Remarks

Our vision at COTI is to empower users to freely exchange value as simply as information is exchanged on the Internet. Our Trustchain Protocol can be utilised by any industry that needs high throughput and trust to operate. As such, COTI is uniquely positioned to provide the infrastructure needed for industries requiring immense scalability, in addition to an arbitration mechanism to resolve disputes, fraud (e.g. double spending) and errors.

Check out our latest whitepaper to learn more about COTI.

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COTI is a DAG-based Layer 1, specifically designed for Enterprises. COTI’s Protocol is scalable, fast, private, inclusive, low cost and is optimized for finance