Research on digital copyright protection based on the hyperledger fabric blockchain network technology

Digital watermarking technology

Digital watermarking technology can be used in digital copyright protection (Sheppard, Safavi-Naini & Ogunbona, 2002; Deepa Merin Jose, Karuppathal & Vincent Antony Kumar, 2012; Woo, 2007). Digital watermarking technology is used to embed different iconic information as fingerprint information into digital media, and then distribute it to users. Digital fingerprint information can contain information such as the creator of digital media, the date of generation, and so on. Digital watermarking technology is generally having the characteristics of invisibility and robustness. The purpose of using watermarking technology is to prevent the copy and secondary distribution of illegal users by tracing them.

Although digital watermarking technology can solve many important problems in digital copyright protection, it still possesses some major problems:

1. The technology is cumbersome. There are many technical problems and loopholes. It is difficult to guarantee the unauthorized use of digital copyright works. Work registration, anti-counterfeiting recognition, customer authentication, and authorization, copyright management, and other technical methods of this technology are very complex.

2. Digital watermarking is not mature enough in technology. The extraction effect and the security of watermark information are not guaranteed.

3. Robustness is not strong enough. To ensure the robustness of digital watermarking technology, it is necessary to ensure that watermarking information must be difficult to erase. But in practice, any watermark can be removed, even for some complex watermark information that cannot be completely removed, part of the information can be removed.

Blockchain technology

One of the most auspicious technologies in the new economy is distributed ledger technology, also known as “blockchain”. The World Economic Forum has estimated that more than 25 countries have invested in blockchain technology, applied for more than 2,500 patents, and invested 1.3 billion US dollars (Blockchain, 2020). Klaus Schwab, Founder and Executive Chairman of the World Economic Forum, gives the following definition of this technology: “The blockchain is a shared, programmable, cryptographically secure and therefore trusted ledger which no single user controls and which can be inspected by anyone (Shapiro & Varian, 1999).”

In addition to digital currency, blockchain technology has begun to expand in other areas in recent years, including digital copyright protection (Savelyev, 2017; Fujimura et al., 2015; Xu et al., 2017). Blockchain is a distributed account book with multi-node participation where the data cannot tamper. The scheme allows the node to link and record the transaction data through the Merkle tree for some time. Each block contains not only the transaction data, but also the timestamp identification and the parent block hash Blockchain. Blockchain development goes through the following three stages:

1. 1.0 era. Bitcoin is represented by digital currency applications. As a decentralized payment system, Bitcoin does not rely on any third-party organization, using cryptography technology and the whole network consensus to ensure the security of currency circulation.

2. 2.0 era. Ethereum represents the combination of digital money and intelligent contracts for decentralized applications. Besides serving as a circulation platform for digital money, smart contracts running on Ethernet Square can achieve more business (Christidis & Devetsikiotis, 2016).

3. 3.0 era. Hyperledger Fabric (Androulaki et al., 2018) is represented by permission control and authentication de-central application.

From the point of view of storage architecture, blockchain technology is a chain structure in which each block is connected in the order of timestamp, which involves techniques such as Hash function, Merkle tree, timestamp, and point to point (P2P) network (Wang et al., 2018; Di & Zhusong, 2018; Yang et al., 2018; Lee et al., 2008), etc.

As shown in Fig. 1, the block structure can be divided into two parts: block header and block body. The block header contains the block version number representing the current block version, the hash value of the previous block header, the hash value of the Merkle tree root node generated from the transaction list, the timestamp generated by the block that can be accurate to seconds, the difficulty target representing the mining difficulty value, and the random value used in the mining process. The block body contains the number of transactions in the current block and hash values specific to each transaction, which are connected through a data structure called a Merkle tree.

The hash function also called a hash algorithm, is a method for creating small digital “fingerprints” for any kind of data. A hash function compresses a message or data into a summary that makes the amount of data smaller. This function creates a new hash value called (hash values, hash codes, hash sums, or hashes) fingerprints for the data. Mostly a hash value is a string of short random letters and numbers. Two hash codes rarely have hash conflicts in the input domain. It is very hard to temper or sniff the hash codes for particular data. Furthermore, if two hash values are different than the original input of the two hash values is also different. On the other hand, the input and output of a hash function are not uniquely related. Message-digest algorithm (MD5) (De Guzman, Sison & Medina, 2018), Secure Hash Algorithm 1 (SHA-1) (Ren et al., 2019) and RACE Integrity Primitives Evaluation Message Digest (RIPEMD) (Giechaskiel, Cremers & Rasmussen, 2018), are some common hash functions. The specific hash function used in the blockchain field is the Secure Hash Algorithm 256 (SHA256) function. A blockchain calculates a specific hash value by a hash function, and each block has a hash value of the previous block so that a chain-like data structure is formed between the blocks. The hash function has an important feature that when a hash value is generated for input and the input is modified even if it is only a very small part of it, the new hash value for the same input is completely changed.

According to whether the nodes of the blockchain need to be authenticated to participate in the recording of the block, the blockchain can be generally divided into three types, namely public chain, private chain, and alliance chain. The node of the public chain can be added to the blockchain system without any certification, and the private chain is only open to very limited internal individuals or entities. The nodes of the alliance chain are only open to members and limited third-party members of a particular group. Hyperledger Fabric is a very important alliance chain technology, and the paper use Hyperledger Fabric technology to implement copyright protection systems. The paper will introduce Hyperledger Fabric technology in the next section.

Hyperledger fabric

In December 2015, the Linux Foundation announced the launch of the Hyperledger project, which aims to build an open platform to enable project members to work together, simplify business processes and promote the cross-industry application of blockchains. Unlike Bitcoin and Ethernet Square, which do not have any licensed public chains, the Hyperledger project only allows licensed members to join to have a certain trust base. Therefore, Hyperledger is not completely decentralized but can be considered as an alliance chain.

The fabric uses a modular architectural design. Its core features include the following six aspects:

1. Managing membership certificates using separate Fabric CA projects to facilitate the management of system members;

2. Classify nodes according to the functions of nodes in the system, such as endorsement nodes, consensus nodes, and submission nodes. It decouples the transaction-processing nodes functionally, and also decides the number of different nodes according to the needs of the business;

3. The consensus function is decoupled from other transaction processing links to improve scalability;

4. Setting up multiple channels to completely isolate the data in different channels;

5. Provide pluggable module design, consensus module, user rights management module, accounting mechanism, and so on. Developers can choose different modules according to the different needs of the business;

6. Provides intelligent contracts that support Go, Java, and Node.js languages, which are called system chain codes in the Fabric framework and can handle blockchain systems.

The system architecture of Hyperledger Fabric (Klaokliang et al., 2018) is shown in Fig. 2, which can be divided into four layers from bottom to top:

1. Web application layer, facing the upper business application developer, mainly realizing the front-end module, directly facing the user through the front-end.

2. Smart contract business layer, for smart contract business developers, responsible for the implementation of chain code transactions and other related business code. As a core part of the blockchain, a smart contract is a computer protocol that is designed to spread, verify, or execute contracts in an information-based way. It allows trusted transactions without any third party. These transactions can be traceable and irreversible (Christidis & Devetsikiotis, 2016).

3. Consensus mechanism and authority management, for alliance and organization managers to achieve certificate management and consensus mechanism configuration.

4. The network layer, oriented to system administrators, implements P2P networks and provides the underlying capabilities for building blockchain networks, including nodes and services representing different roles.

Several basic concepts involved in the Hyperledger Fabric are described below:

1. Peer Node: the concept of node originated from P2P distributed network, represents a service or software that undertakes certain functions in the network. In the Hyperledger Fabric network, by functional role, the Peer node (Park, Hwang & Kim, 2018) can be divided into five types. The certificate node is responsible for issuing registration certificates to nodes and users; a submission node (submitter) is responsible for generating proposals and distributing them to the relevant endorsement node; endorsement node (the endorser) is responsible for the execution of the contract and endorsement response; a sort node (orderer) is responsible for sorting proposals, block packing; Confirm node (committer) is responsible for verifying the validity of the contract execution results, maintaining the blockchain and ledger structure. These roles are logically divided, not mutually exclusive. Usually, most nodes in the network have validation functions, while some nodes have an endorsement or sorting functions.

2. Chain code: the chain code in the Hyperledger Fabric (Linux Foundation, 2019), that is the intelligent contract mentioned above, is the medium for the upper application to interact with the underlying blockchain platform. Currently, Hyperledger Fabric support Go, Java, and other programming languages chain code. All chain codes inherit Init and Invoke interfaces. Init interface for initializing contracts, the interface is executed only once throughout the chain code life cycle. Invoke interface is essentially used to add and delete the underlying database of Blockchain. Different business logic can be distinguished according to the function name passed.

3. Channel: Channel (Gupta et al., 2018) provides a private channel for data exchange for nodes in the network. The node of the same channel can share or manage all books in the channel. One node can be added to multiple channels, managing multiple books, but the books of each channel are isolated. Therefore, the channel is a logical structure, which consists of physical nodes. Super books provide access channels and management channels.

System architecture

As discussed earlier, the paper proposes the following system structure, as shown in Fig. 3.

The system includes the copyright owner, the copyright receiver, and the distributed deployment of smart contracts, which can achieve a variety of business functions.

The workflow of the whole system is shown in Fig. 4.

The detailed description of the whole process is as follows:

1. User registration: all users must register before using the system;

2. Copyright registration: the copyright owner registers the copyright of the digital works on the system. During the registration process, the fingerprint information of the digital works needs to be extracted and stored on the blockchain;

3. Copyright query: before purchasing the copyright, the copyright receiver needs to call the smart contract to verify and query whether the copyright to be purchased is owned by the copyright owner i.e., to confirm the right of digital copyright. If the right is not confirmed, the process will be terminated, otherwise, it will go to the next step;

4. Copyright transfer: after the copyright receiver purchases the copyright and pays the corresponding consideration, the copyright owner calls the smart contract to transfer the copyright to the copyright receiver, and the whole process ends.

According to the specific requirements of digital copyright protection, this research has implemented the following five modules as shown in Fig. 5: user registration module, digital copyright registration module, information query module (including digital copyright query module, user query module, and digital copyright transaction history query module), digital copyright transfer module and user cancellation module.

User management

User management is mainly divided into the following two modules:

(1) User registration module

The user registration module requires the user to fill in his name and Identity document (ID). The ID attribute cannot be repeated for the registered user. The user can also selectively enter basic information such as the mobile phone number and the work unit. The flow chart of the user registration module is shown in Fig. 6.

(2) User logout module

If the users need to cancel the accounts, they only have to enter the ID of the required cancellation account to cancel it. After account cancellation, the digital copyright also gets canceled. The flow chart of user logout is shown in Fig. 7.

Copyright management

Copyright management is mainly divided into the following three modules:

(1) Information query module

Users can choose three query modes to inquire information: digital copyright information query, user query, and digital copyright transfer record query. If the user enters the copyright number for the information query, it can query the relevant information of the copyright and the current owner of the copyright. When the user enters the user ID for the information query, he can query the user’s relevant information and all the copyrights currently owned. When the user makes a copyright transfer history query, he can view all transfer records from registration to date. The flow chart of the query module is shown in Fig. 8.

(2) Copyright registration module

Users need to enter the digital copyright number (the copyright number cannot be the same value as the registered copyright), the copyright name, and the copyright type, and upload the corresponding digital file. Another program converts the uploaded digital media files, and the transferred hash values are stored on the blockchain with copyright information. The flow chart of the copyright registration module is shown in Fig. 9.

(3) Copyright transfer module

The user is required to enter the copyright number, ID of the copyright owner, and the copyright granter ID for the copyright to be transferred. During this step, the copyright transfer will also get updated at the same time. Furthermore, the transferred copyright is removed from the transferor side and is added to the copyright information owned by the grantor. The flow chart of the copyright transfer module is shown in Fig. 10.

Data structure design

For the storage system of digital copyright protection, the required parameters of each module are designed according to the traceability requirements of each module. The system involves three entities: user, digital copyright, and copyright change history. The relationship is shown in Fig. 11.

All entity-specific parameters in the system are designed as shown in Tables S2–S4.

The user can query the user’s information by entering the user ID, user’s basic information, and the copyright number of the copyright owned by the user, which is the interactive object of this system. In the copyright transfer operation, the user also needs to enter the original owner of the copyright and the user ID of the grantor.

Digital copyright is the core entity in this system and almost all the user’s operations involve this entity. The Metadata parameter of digital copyright is the hash value of digital media files uploaded by users after digital fingerprint extraction. This prevents the files uploaded by users from being tampered with.

When the user performs a copyright transfer operation, the corresponding copyright change records get generated with the copyright ID, and then all the transfer records of particular copyright can be viewed in the subsequent copyright transfer query.

Each ledger maintained by peer nodes in the Blockchain system consists of two parts: World state and Blockchain. The world state stores the latest values of all the transaction states, and the Blockchain system stores the data in the form of blocks.

System implementation

The Hyperledger Fabric network uses a single-machine multi-node network configuration with the start-up type solo. The network configuration of the system is networked with a sorting service node and peer nodes under two organizations, where each organization includes two peer nodes. In this implementation of the system, the listening port number of the orderer sorting service is set to 7050.

In the Hyperledger Fabric, the smart contracts are called chain codes. The smart contract will be installed and instantiated on a peer node service by an authorized member. Then, some business personnel can use a client that can execute the Fabric-Software Development Kit (Fabric-SDK) to interact with the peer node service to obtain the smart contract call.

The following is the structure defined in the smart contract, and the specific parameters are as follows:

  type Digitalright struct {

      Name string `json: “name”`

      Id string `json: “id”`

      Type string `json: “type”`

      Metadata string `json: “metadata”`

    }

  type DigitalrightHistory struct {

      DigitalrightId string `json: “digitalright_id”`

    OriginOwnerId string `json: “origin_owner_id”`

      CurrentOwnerId string `json: “current_owner_id”`

    }

  type User struct {

    Name string `json: “name”`

    Id string `json: “id”`

  Tel string `json: “tel”`

      Gender string `json: “gender”`

    Address string `json: “address”`

      Password string `json: “password”`

  Digitalrights []string `json: “digitalrights”`

  }

In this work, chain-code is used to implement complex business logic. In the proposed methodology, the Go programming language is used to develop the chain code. All functional interfaces that are included in the smart contract are shown in Table S4.

The Smart contracts will run on public channels and all the users can write their identity and copyright information into the blockchain to complete the copyright transactions. After the data is written into the blockchain network, it cannot tamper and it is added to the public channel. All peer nodes of the channel can also query all transaction information in the channel. The following steps briefly introduce the five main algorithms involved in the smart contract:

• 1. Algorithm 1 User registration

• Input: username, userId, tel, address, password, gender

• Output: if success, return transaction data else throw an exception

• Description: Before writing the user information to the blockchain, the user information is authenticated. If all the steps are passed normally, the user Register function will call the JSON.Marshal interface for the data sequence and then stub.PutState will be called to store the data on the blockchain.

• 2. Algorithm 2 Registration of copyright information

• Input: digitalrightName, digitalrightId, digitalrightType, metadata, ownerId

• Output: if success, return transaction data else throw exception

• Description: Before writing the copyright information into the blockchain, it will first verify the legality of the copyright information and checks whether the copyright (digitalrightId) number already exists or not. If the copyright information is legal and valid, it will verify whether the copyright owner (ownerId) has been registered already. If so, the registered user will first serialize and then deserialize the user’s copyright information to update user information. After completing the update process, a record will be created and added to the copyright transaction history.

• 3. Algorithm 3 Copyright transfer

• Input: digitalrightId, ownerId, currentownerId

• Output: if success, return transaction data else throw an exception

• Description: While performing the copyright transfer, it will first check whether the copyright number (digitalrightId) of the copyright to be transferred exists. If it exists, it will match whether the current owner is currently entered (ownerId) and whether the transaction user (currentownerId) is a registered user. After completing the verification, the acquired user information gets serialized and then deserialized to update the copyright information. Finally, a copyright change record of the transaction will be inserted.

• 4. Algorithm 4 Information query

• Input: digitalrightId, ownerId, queryType

• Output: if success, return query result else throw an exception

• Description: The query function is divided into three parts: user query, copyright query, and copyright transaction record query. When the user performs a user query or copyright query, the query ID (ownerId) or copyright number (digitalrightId) entered by the user is verified. Registered users or registered copyrights will get the corresponding query information. During the copyright transaction record query, the operations will be performed according to the type of query requested by the user (queryType).

• 5. Algorithm 5 User Delete

• Input: userId

• Output: if success, return transaction data else throw an exception

• Description: The user logout module will first verify the entered user ID (userId) to get it logged out from the system. The stub.DelState interface is called to delete user information and at the same time, it will reverse the sequence of the user information and then again the stub.DelState is called. Finally, the interface deletes the copyright owned by the user.

Experimental environment

This paper used the following testing environment in Tables S5 and S6:

The system was built using Hyperledger Fabric version 1.0. The paper used the “docker-compose -f docker-orderer.yaml up –d” and “docker-compose -f docker-peer.yaml up –d” to start the ordering service node and peer node. “docker ps” command was used to check whether the container is successfully started. The container query result is shown in Fig. S1, where the ordering service and peer node both started successfully.

After all the containers were started successfully, the next step was to create a channel (channel) and join the operation. Since there is no third-party SDK to make the join, the joining of the channel only needs to enter the started client (CLI) to operate. The channel was created using the command “Peer channel create -o orderer.example.com:7050 -c mychannel -t 50 –f ./channel-artifacts/mychannel.tx”. This command defines the channel ID to be created as mychannel. After the channel is created, the file is blocked after joining, and the start of the fabric network is completed.

Test case

When designing the test data, all functions of the system should be tested. At the same time, possible events should be taken into consideration so that the system can be fully tested, to judge whether the system meets the design requirements. Tables S7–S9 shows system construction data (the construction data is only for testing the functions implemented by the smart contract).

Test results

During the user registration function test, the “peer chaincode invoke -C mychannel -n mychannel -c‘{“Args”: [“userRegister”, “Piff”, “522003”]}”’ format commands are used for network interaction. When the user's input parameters meet the requirements, the system will prompt success, else the system will report the corresponding error. The test results are shown in Figs. S2–S4.

When testing the copyright registration function, use peer chain code invoke -C mychannel -n mychannel -c‘{“Args”: [“assetEnroll”, “Manta”, “20191101”, “213214123123”, “522001”]}’ format The command interacts with the system. Similarly, when the user inputs parameters that meet the requirements, the system will prompt success. When the user enters an existing copyright number, a non-existent user ID, or does not enter enough parameters, the system will report a corresponding error. The test results are shown in Figs. S5–S8.

During the test of copyright transfer functions, the command of peer chain code invokes -C mychannel -n mychannel –c‘{“Args”: [“assetExchange”, “user1”, “522001”, “522002”]}’ are used where the user Sean The “Blooming” owned is transferred to the user Lexie. After the operation is successful, the target copyright and the information of both users get updated. When the user enters a non-existent copyright number, a non-existent user ID or it does not enter enough parameters, the system will report the error. The test results are shown in Figs. S9–S12.

The query function involves three parts: user, copyright, and copyright transaction record query. The logic of the query function is similar, that’s why only the results of successful queries are displayed. As shown in Fig. S13, the query for the user with ID “522002” has returned the user’s basic information and all the copyright number information. Figure S14 shows the result of querying the copyright number “19980722”, which correctly returns the copyright name, ID, and hash value of it. Figure S15 shows the results of querying the copyright number for which the results are returned including all transaction records of “19980722” (including copyright registration).

Result analysis

We have presented a comparative analysis in which we have compared our proposed methods with already developed similar methods to prove the efficiency. Table S10 shows a comparison of the proposed model with other similar models. The comparative analysis is performed based on five aspects.

1. Whether it supports the whole life cycle management of copyright;

2. Whether a lot of calculation is needed;

3. Whether it supports the digital copyright protection of different types of files;

4. Whether the data storage on the link needs to pay a fee;

5. Whether it supports smart contracts or not.

It can be seen from the above tables that, only the proposed scheme supports the whole life cycle management. Other schemes need a lot of calculation for using public blockchain (Zhao & O’Mahony, 2018) or using homomorphic encryption (Liang et al., 2020) or using watermarks technology (Ambili, Sindhu & Sethumadhavan, 2017). Only this scheme support protection of different types of files. The scheme is needed to pay the fee by using Ethereum (Zhao & O’Mahony, 2018). The other compared schemes do not support smart contracts (Liang et al., 2020; Ambili, Sindhu & Sethumadhavan, 2017; Tsai et al., 2017).

According to the previous comparative analysis, the system can realize the automatic management of the whole life cycle of digital rights on the blockchain by using fabric’s smart contract technology. The whole life cycle of digital rights includes the registration, transfer, and query of digital rights and so on.

Because the data on the blockchain has the function of distributed storage and tamper proof, all the data about the whole life cycle of digital rights are stored on the blockchain. In this way, the data stored in the system has authority and credibility, preventing the theft of digital rights, and realizing the effective protection of digital rights.