MAP Protocol
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MAP Protocol

Technology Overview (1)-Characteristics and Three Core Sub-modules

MarcoPolo Protocol Overall

MarcoPolo Protocol is an open, fully decentralized, chain-to-chain interoperation protocol that enables the interoperability of multiple independently verifiable consensus blockchains without a relay chain. MarcoPolo Protocol expects to construct a future inter-chain-net, which is interoperable and chain-to-chain based. The ecosystem built on MarcoPolo Protocol can provide a solid infrastructure for finance, AI, IoT, traceability, and governance filed by cross-chain communication, privacy computation, shared storage, etc…

Interoperable Protocol’s Characteristics

Unlike other cross-chain platforms with many restrictions, MAP is committed to creating a free inter-chain protocol. The goal of MAP is to build a large-scale open collaboration infrastructure with a large number of interoperable blockchains, which can serve various DAPPs. By building a free interchain protocol that ensures interoperability between chains, each future blockchain can interoperate with other blockchains through this protocol, and each DAPP can be freely selected according to the usage scenario and configure the underlying features required by it, you can choose the one with the higher degree of decentralization, or with higher scalability or privacy computing.

In order to support such functions, MarcoPolo Protocol has three key characteristics:

MarcoPolo protocol Three Key Characteristics
  1. Succinctness: This protocol will not occupy too many network resources and storage resources.
  2. Reliability: This protocol will ensure the security of interoperation, that is to say, the data obtained by any node must be consistent with that obtained by all nodes of the corresponding chain.
  3. Universality: This protocol only regulates interoperable modules and does not add any other requirements, constraints, or restrictions to other blockchains in the ecosystem.

While meeting all those characteristics, MarcoPolo Protocol includes three core sub-modules.

(1) Ultra-light local chain verification protocol

(2) Ultra-light cross-chain verification protocol

(3) Smart script with combinable trigger conditions

Three Core Sub-modules:

Ultra-light Local Chain Verification Protocol

Lightweight local chain verification protocol is not only a prerequisite for MAP but also a way for most users to use and participate in the blockchain world in the future. If the blockchain is considered as a distributed database, then the database’s writing power is determined by the consensus algorithm, which is only available to a few full nodes that have historical data. For a larger group of users, the need for reading data from the shared database is required. However, the existing blockchain technology does require users to download the entire blockchain and related state information and save it locally, or at least download a block header chain and save it locally, meanwhile they need to update the header chain frequently. Most Bitcoin holders do not yet know how to maintain a full node and send transactions. They usually proxy their own Bitcoin through cryptocurrency exchanges. Such use will cause serious security risks and also bound the blockchain usage.

The purpose of MAP is to create a prosperous blockchain ecological system. Therefore, ensuring users to benefit from blockchain technology like using traditional Internet products while maintaining a good user experience is the priority. In order to meet this demand, we need an ultra-lightweight local chain verification protocol to ensure that any node on the local chain can verify the status of transactions with low bandwidth and low storage.

The ultra-light verification technology can ensure that the network communication cost and local storage cost required by users when acquiring data on the chain are sublinearly related to the length of the chain.

For example, if the block height is 1,000,000, the user needs to store 1,000,000 block header data to their local storage in SPV circumstance. However, using ultra-light node verification technology, the data required for the same verification is roughly proportional to the logarithm of 1,000,000, which is about 1,000 block-size data. This amount of data can be obtained through instant transmission without the need for local storage. Therefore, many existing terminals can directly access the P2P network of the blockchain to obtain information on the chain, rather than through the proxy server. This design not only improves security but also ensures simplicity and satisfies the user’s good experience.

Ultra-light Local Chain Verification Protocol will meet two goals:

  1. Security: The protocol must ensure that the state information that the ultra-light verification node gets is consistent with the information the full node hold. It should be noted here that the security we are talking about is the security of the verification protocol itself, not the security of the chain itself. For example, the full nodes of the POW chain cannot resist 51% attacks, and the ultra-light verification nodes can not resist the same attacks either. However, the protocol can guarantee consistent information for each node cryptographically.
  2. Succinctness: The protocol must ensure that the network resources and local storage resources consumed by the verification node when acquiring the status information on the chain are sub-linear growth, that is, they do not increase significantly with the height of the chain. The succinctness will allow MAP to be used on large-scale scenarios; if succinctness cannot be guaranteed, the protocol cannot be used on a large-scale even if it is safe, which is why most blockchains have not been popularized so far.

Key Technologies:

  1. NIPOPOW (Non-Interactive Proofs of Proof-of-Work): this will provide ultra-light proof that can be applied to the POW type of public chain
  2. Flyclient technology: this technology was first mentioned in Benedikt Bunz’s article “FlyClient: Super-Light Clients for Cryptocurrencies”. The Flyclient technology will promote NIPOPOW to any Proof-of-X public chain (POW, POS, POET, etc.) and provide the implementation of this technology in the Grin project.

Ultra-light Cross-chain Verification Protocol

The ultra-light local chain verification protocol we mentioned in the previous section is designated for the single-chain system. We can extend this protocol to a multi-chain system, making it a normative verification standard, providing a basic protocol that can mutually verify information between two blockchains and make them interoperable.

In order to make two blockchains interoperable, we will need all the nodes of the blockchain to carry out data transmission under the unified underlying communication protocol and establish a unified on-chain information verification specification.

Ultra-light Cross-chain Verification Protocol will meet four goals:

  1. Security: Like the local chain verification protocol, the cross-chain verification protocol needs to ensure that the protocol itself has sufficient security.
  2. Simplicity: Like the local chain verification protocol, the cross-chain verification protocol must ensure that the network resources and storage resources consumed are very low.
  3. Non-interactive: The cross-chain verification protocol must ensure that the verification process is non-interactive, that is, the final result cannot be obtained through multiple rounds of question and answer communication.
  4. Transferability: The cross-chain verification protocol should ensure that the verification results are transferable, which means that the verification results can be broadcast to any node through any node without additional calculation.

Key Technologies:

  1. Probability Sampling: Using probability sampling to obtain a small block header set with O(log n) length from a blockchain with the height of n, so that the total difficulty of the set and the total difficulty of the blockchain have a similar order of magnitude.
  2. Merkle Mountain Range (MMR) Verification with Variable Difficulty: Using Merkel Mountain Range verification, an efficient and difficult variable commitments mechanism, allows provers to provide a logarithm length proof to prove the current length of the chain. At the same time, the difficulty information will be embedded in the MMR, so that the verifier can track the change of the difficulty.
  3. Non-interactive Transferable Proof: The evidence provided by the prover does not need to be interactive, which means that any node can independently verify the validity of the evidence locally. At the same time, the evidence can be directly passed to other nodes for validation.

Smart Script with Combinable Trigger Conditions

When the lightweight local chain and cross-chain verification can be achieved, it is necessary to consider the specific interoperability execution steps. Any operation on the chain is triggered by certain pre-events. Once these specified pre-events are triggered, subsequent events can be executed in sequence. For multi-chain systems, the triggering mechanism of the operations on the chain is more complicated. We can summarize them into three categories:

  1. The Status of the Chain: for example, the length of the chain, whether there is a transaction in a block, the balance in an account, the tokens in a smart contract, etc. This information can be obtained directly from all nodes of the chain through the chain verification protocol.
  2. Other Non-chain Verifiable Information: such as pre-image mapping of hash locks, transaction signatures, zero-knowledge proof functions, etc. This type of information can be independently verified locally by any node, generally some cryptographic evidence. This information can generally be obtained in webcasts.
  3. On-chain Status on Another Chain: for example, the length of another chain, the account status of another chain, etc. We need to obtain this kind of information through the cross-chain verification protocol mentioned above.

· MarcoPolo Protocol Twitter and Telegram Channel (For the latest news)

· MarcoPolo Protocol Telegram Community: English, Россия, Türkiye, Việt Nam, Brazil, and Indonesia; Korean Kakao Community: 코리아

· MarcoPolo Protocol Medium (For the latest articles)

· MarcoPolo Protocol WhitePaper, and Roadmap

· MarcoPolo Protocol GitHub (For the complete codes)

For more information, visit



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MAP Protocol

MAP Protocol

The Omnichain Network for An Interoperable Web3