Understanding CESS: The First Decentralized Storage Network to Meet Commercial Storage Needs

Author: Jiang Haibo, PANews

The collective disconnection of internet giants once again tolls the "death knell" for centralized networks.

On June 21, 2022, a global network infrastructure service provider, Cloudflare, experienced a failure that caused hundreds of major websites to go offline, including giants like Discord, Medium, Coinbase, NordVPN, and Feedly. This widespread disconnection caused by a "single point of failure" has led more people to reconsider the necessity of decentralized storage networks.

Blockchain advocates for decentralization, but so far, storage has been a weak point in decentralization. On one hand, the front-end and middleware of blockchain projects are deployed on centralized servers, making them vulnerable to attacks; on the other hand, data from NFTs, GameFi, and other applications has not achieved decentralized storage. Therefore, providing an effective solution to these existing problems will create a new business model—how to achieve decentralized storage for blockchain network nodes, NFTs, and GameFi, and deploy streaming or social media on decentralized networks.

The Web3 Journey of CESS

The term Web 3 was interpreted by Gavin Wood in 2014 as a new generation of the internet brought by blockchain technology. At that time, Gavin was still the co-founder and CTO of Ethereum and had not yet established Parity and Polkadot. In 2016, Polkadot was launched to realize the multi-chain vision of Web3, addressing the "island" problem between blockchains, allowing applications and services on the chain to communicate securely across chains. CESS, short for Cumulus Encrypted Storage System, is a decentralized infrastructure developed based on the substrate framework. It not only provides a universal storage module for the entire Polkadot ecosystem (meaning that Polkadot ecosystem projects can integrate with CESS's storage module to store data in the CESS storage system and also call this data on-chain) but also offers decentralized data cloud storage solutions for the entire Web3 world and some Web2.0 enterprises.

Compared to other decentralized storage projects, CESS addresses issues such as high costs, slow retrieval, and slow upload/download in the decentralized storage application process through innovations like a randomly selected rotating consensus node mechanism, multi-replica recoverable storage proof, multi-type data rights confirmation mechanism, and proxy re-encryption technology, enabling decentralized storage to meet the commercial application needs of high concurrency and timely dissemination, such as streaming media. CESS can also support common applications similar to decentralized Baidu Cloud and decentralized Google Cloud, and even support new-generation applications like GameFi and the metaverse, which have high demands for on-chain data interaction.

In the Polkadot ecosystem, CESS is a "top student." At the 2021 Asia-Pacific Hackathon of Polkadot, CESS LAB won the first prize in "Build a Blockchain"; on January 25, 2022, CESS completed all deliverables required by the Web3 Foundation (W3F) Grant; on March 7, 2022, W3F approved CESS's grant proposal to provide storage modules for Substrate again. On June 29, 2022, it completed all deliverables regarding "CESS providing storage for Substrate" and passed the milestone 1 of the SBP (Substrate Builders Program).

During Polkadot's largest global event, Polkadot Decoded, CESS's China community manager, Andy Zou, pointed out the pain points of the current decentralized storage track in his presentation in Hangzhou and proposed CESS's solutions, such as using a multi-replica recoverable storage proof mechanism to address the single point of failure in traditional storage. CESS is the first decentralized storage network to provide space storage services. CESS's global market operations manager, John Humphreys-Ramos, introduced the randomly selected rotating consensus node (R²S) mechanism at the Buenos Aires venue, which addresses the "miner dilemma," ensuring that the storage of block history is more decentralized and preventing excessive centralization by large miners that could be detrimental to the overall development of the network.

Global business development director Louis Albuerne mentioned at the New York venue that CESS uses proxy re-encryption technology and a multi-type data rights confirmation mechanism (MDRC) in decentralized storage. The former is a key conversion algorithm that can convert ciphertext encrypted with the data owner's (authorizer's) public key into another ciphertext, which can be decrypted by the data user's (authorized person's) private key without revealing the data owner's private key and plaintext information, enabling free trading and sharing of data among CESS ecosystem users. The latter refers to the process where, when users upload data to the CESS storage system, the network extracts digital fingerprints from the data, puts the fingerprints on-chain, and compares the fingerprints to track and trace the data within the CESS network.

CESS's testnet was launched on July 5, and it will be rolled out in several phases, continuing to add new modules and features.

Technical Innovations of CESS

Randomly Selected Rotating Consensus Node Mechanism R²S

Although CESS is primarily used for storage, as a public chain, it also needs to reach consensus on how to package transactions. Its consensus layer must consider issues of network security, performance, and decentralization. In a blockchain network, there are many nodes, and CESS randomly selects a portion of these nodes to maintain consensus, a mechanism known as the randomly selected rotating consensus node mechanism (R²S).

The logic of R²S is to balance network security while achieving low gas fees and high TPS. The network randomly selects 11 formal rotating nodes from all eligible candidate nodes, which are the consensus nodes responsible for completing block production and other consensus maintenance tasks during a certain period. Candidate nodes must also maintain continuous contributions to the network, completing tasks such as data sharding, encryption, and redundancy, which determines whether they can participate in the next time window's rotating node competition. The network will also select rotating nodes for the next time window during this period.

To improve on-chain transaction processing efficiency while ensuring node decentralization, CESS employs the innovative randomly selected rotating consensus node mechanism (R²S) to achieve block packaging and other on-chain transactions. The key focus of this mechanism is on "randomness" and "consensus," meaning that a certain number of rotating nodes will be responsible for maintaining consensus within a time window, and the randomness of selection ensures complete decentralization. The consensus mechanism is core to the decentralized storage network, and the CESS team has made special considerations for storage public chains in designing this mechanism.

On one hand, the R²S mechanism separates consensus from storage, preventing the "miner dilemma" and monopoly. On the other hand, it uses Trusted Execution Environment (TEE) technology to periodically check the honesty and scheduling capabilities of consensus nodes, ensuring that nodes provide efficient services to the network through fair competition.

Multi-Replica Recoverable Storage Proof PoDR²

The multi-replica recoverable storage proof (PoDR²) mechanism ensures that the CESS storage network effectively stores the customized replicas of user-uploaded data. That is, once any piece of data is uploaded to the network, it will automatically be copied into several data replicas, generating the metadata required for auxiliary verification of recoverable proof for each data replica, which is then stored in the network.

As the core mechanism of the CESS storage network, the biggest advantage of the PoDR² storage mechanism is that CESS has implemented encryption, redundancy, and other protection strategies in its underlying design. Storage miners only need to store the processed data segments and ensure the validity of the storage. Even if some miners lose data, the network can restore the original data through other data segments. This mechanism will monitor and track all data segments that make up a single file as a whole. Once a data segment is identified as damaged, CESS will automatically generate a new data segment as a supplement and send it to new storage miners, ensuring the recoverability of replicas and enhancing the overall robustness of the storage network. This mechanism greatly reduces the possibility of single points of failure and improves the security of data within the overall CESS storage network.

Multi-Type Data Rights Confirmation Mechanism MDRC

Web3 allows data ownership to return to users, and decentralized storage has already seen cases of user "confirmation" of rights. CESS's multi-type data rights confirmation mechanism extracts data fingerprint files from each data to generate a data certificate ID. Any individual or enterprise can register their creative achievements, benefiting from the immutable nature of blockchain.

Proxy Re-Encryption Technology

Centralized storage inevitably carries the risk of data leakage, leading to a crisis of trust in the internet and cloud technology.

To ensure user data security, CESS has designed a decentralized proxy re-encryption mechanism that allows data owners to convert data between themselves without revealing the content of the data. That is, data uploaded to the CESS storage network is by default marked as either public or private. If a user chooses the private state, the network will encrypt each segment of data and then send it to global storage miner nodes for storage. If the user chooses to authorize the data to others, this mechanism will authorize encryption on the data stored on the storage miner nodes, allowing the designated object to use the data private key for decryption, achieving secure access to the data.

Multi-Layer Network Design

"Modularity" is a development trend for the future of blockchain. Modular blockchains only need to focus on a few functions of the blockchain rather than implementing all functionalities. For example, Rollups like Arbitrum and Optimism focus on scalability, while Celestia is used for consensus and data availability, all representing modular blockchains.

In fact, many public chain projects have also adopted a multi-layer modular design to achieve complete blockchain functionality, such as the execution layer and consensus layer of future Ethereum, and the relay chain and parachains of Polkadot.

CESS decided to build a complete blockchain architecture rather than just designing it as a module because its blocks need to include not only transactions and storage proofs but also records of the entire network's storage space and storage content metadata. The network architecture of CESS can be divided into four layers: blockchain service layer, distributed storage resource layer, distributed content distribution layer, and application layer.

1. The blockchain service layer handles all transactions and contracts, including consensus algorithms, storage proofs, payments, and incentives. The specific consensus algorithm has been introduced above, and the nodes participating in consensus are also referred to as consensus miners.
2. The distributed storage resource layer is the network used to store user-uploaded files, data, and other information. Storage miners can submit storage proofs to earn rewards. When planning storage space, CESS's consensus miners use "pooling" technology to intelligently manage all storage space, forming a decentralized cloud storage pool, and then randomly distribute the sharded data segments to miners that meet the requirements, maximizing the effective use of dispersed storage space, avoiding monopolization by large miners, and achieving intelligent cloud space management.
3. The distributed content distribution layer acts as a decentralized content delivery network (CDN), collaboratively completing rapid content delivery in a distributed manner. CESS's content distribution layer includes retrieval miners and caching miners.
4. Above the application layer, various applications can be built. Compared to other decentralized storage service providers, CESS not only provides distributed storage services but also aims to build a truly cloud storage ecosystem. CESS is a public chain developed using Substrate, which supports WASM and will also be compatible with EVM, providing convenience for project migration and development.

The entire architecture design includes four types of miners: storage miners, consensus miners, retrieval miners, and caching miners, who operate independently yet collaborate to ensure the normal operation of the network. On this basis, developers can build various applications on CESS.

Because various miners can focus on their respective tasks, the threshold for storage hardware participation in CESS has been lowered, requiring only 1 TB of storage space to become a storage miner. Miners will randomly receive data segments, which does not depend on the scale of the miners themselves. The retrieval miners and caching miners in the content distribution layer also do not need to engage in storage-related tasks, allowing CESS's retrieval, upload, and download speeds to meet the needs of commercial applications.

Applications

In addition to the various technologies mentioned above, at the user level, the biggest difference between CESS and other decentralized storage projects is that it can provide dynamic data storage services.

This means that CESS has pioneered the provision of space storage services in the decentralized commercial storage track, allowing users to modify and delete data at any time, with rapid retrieval and data return that meets the high-frequency, low-cost demands of commercial storage.

Therefore, CESS can meet various application scenarios such as streaming media, social applications, NFTs, GameFi, and medical/research trading and sharing platforms. CESS also plans to use oracles to track the prices of other decentralized storage projects, ensuring that the storage costs for CESS customers do not exceed those of other projects.

Token Economy

CESS tokens can be used to purchase resource services, pay network gas fees, stake nodes for mining, incentivize DApp development, and reward miners for maintaining the normal operation of the CESS network. The total issuance of CESS tokens is 10 billion, with the specific token distribution as follows:

• 15% allocated to early contributors, totaling 1.5 billion, released linearly over 6 years;
• 55% allocated to miners, totaling 5.5 billion, released linearly, halving every 4 years;
• 10% allocated to the community and DAO, totaling 1 billion;
• 5% allocated to business partners, totaling 500 million;
• 5% reserved as a reserve fund, totaling 500 million, for emergencies and future ecological development;
• 10% allocated for financing, totaling 1 billion, for public investment and strategic investment.

Conclusion

As the first decentralized storage network dedicated to meeting commercial storage needs, CESS has made outstanding contributions to the innovation and progress of current decentralized storage projects and commercial storage service design concepts through technological innovations such as the multi-replica recoverable storage proof mechanism, which protects data privacy and security, and the pooling of data resources, maximizing storage resource utilization. In addition, CESS can meet decentralized storage applications in various scenarios.

Based on the Substrate framework and starting from the Polkadot ecosystem, the CESS network aims to create a grand vision for the CESS ecosystem, providing solutions for the infrastructure of various decentralized applications, supporting WASM, and also being compatible with EVM smart contracts. This provides global developers with an efficient decentralized application development model and paves the way for the rapid development of CESS.