In this paper, we present a blokchain solution, based on Hyperledger Fabric, for issuing and validating documents from Higher Education Institutions (HEIs), such as diplomas and diploma supplements. By utilizing Hyperledger Fabric, the most popular distributed ledger technology for private blockchains, we propose a lightweight and secure credentialing three layer blockchain system - the smart contract layer, the blockchain layer itself, and the network layer. With a minimal needed number of functionalities such as issuance and verification, our lightweight system can be deployed on a trustful environment, e. g. faculties from the same university, or a consortium of universities. With such an environment, we eliminate the need for a computationally complex consensus mechanism for adding blocks to the ledger, while retaining easy implementation with the HEIs information system and/or learning management system. Based on previous research and prototyping, our model acts as an additional security layer on top of and HEI's information system and utilizes blockchain's immutable property to keep student's records secure.
ify the validity of certificates in a direct manner, without
contacting the HEI that originally issued the documents
Blockchain technologies (BCTs) and distributed ledger [
Credentialing solutions for Higher Education Institu- date credentials, and other lightweight approaches are
tions (HEIs) based on blockchain and similar technologies needed.
are still few. As of writing this paper, only a small number Since the initial hype of using BCT/DLT for various
of papers have been published [
Indeed, in a trustless environment where actors are not
known, public BCTs with robust consensus mechanisms
such as Biction are imperative [
The authors’ main motivation is to utilize a trustful en- signature, thus enablig the ledger to be resistant to modvironment and propose a lightweight framework for doc- ifications. This chain of blocks that is formed and conument credentialing, tailored specifically to HEIs and the tinuously updated can be traced back all the way to the issuance and validation of student diplomas and diploma first block, named the genesis block. supplements. The combination of peer-to-peer networking, public
Based on literature, commercially (un)available solu- key cryptography, and distributed consensus is what tions and our own previous attempts, we have identified secures blockchain transactions. Conversely to a centralthe following research questions: ized system, no single entity i.e. node should be able to control the process of adding a block to the chain. As • RQ1: Is it possible to design a lightweight frame- the blockchain is a distributed system, each new block work for the specific needs of HEIs to incorpo- addition is managed by all nodes who share equal rights. rate document issuance and validation in a secure This mechanism is utilized in order to overcome secumanner, without relying on complex solutions? rity issues, and is achieved through the process known • RQ2: Can the flexibility of Hyperledger Fabric as distributed consensus. This process can be viewed be used as a basis for incorporating a BCT/DLT- as an agreement among the nodes in the network how based addition to an existing HEI information to validate each block yet to be added to the chain. Desystem (IS)? pending on the consensus mechanism, nodes can either The rest of the paper is organized as follows. Section compete for correct transaction validation (PoW), be cho2 gives a brief introduction on blockchain technolgies, sen randomly (PoS and its variations), or apply a diferent focusing on Hyperledger Fabric. Afterwards, Section algorithm altogether. The algorithms used can vary in 3 gives presented the proposed system, developed at computational complexity.
Belgrade Metropolitan University’s (BMU’s) Blockchain Finally, it is important to note that blockahins are a Technology Laboratory. Finally, Section 4 gives a con- class of technology; the term refers to diferent forms of clusion, with current limitations and further research distributed databases with variations in their technical ideas. and governance arrangements and complexity. 2.2. Hyperledger and its use cases
cused on developing various stable frameworks, tools and
In this Section, we firstly provide a briew overview of libraries for enterprise-grade distributed ledger
deploythe building blocks of a general blockchain system. Af- ments [
The core Hyperledger-based use cases include banking,
healthcare, supply chain management, financial services, BMU’s ongoing internal R&D includes
implementinformation technology, government, and media and en- ing blockchain in education and e-learning. BMU’s
tertainment. Indeed, the Hyperledger Foundation pro- Blockchain Technology Laboratory (BCT Lab) is
investimotes a range of business DLTs, including many libraries gating which blockchain technology is most suitable for
and tools that provide support for the creation, mainte- applying in education, with emphasis on data protection.
nance, deployment, providing cryptographic work, etc BMU’s BCT Lab is collaborating with ISUM
(Informa[
For the proposed system, the authors have opted to Learning center. During a four month testing developing use Hyperledger Fabric, as it is the Hyperledger project and period, a working prototype for credentialing was with most testing, working real-world applications com- developed. The proposed model is comprised of three munity, and documentation. The details of Hyperledger layers, stacked on top of the zeroth layer, which is the Fabric are listed in Table 1. HEI’s IS:
the data to a block. It is present on every node, denoted as a peer. The blockchain layer consists of the peer itself, a Certification Authority (CA) for that peer, and a local Figure 3: Asynchronous promise function. NoSQL database - CouchDB. The network layer consists of the test network with two peers, denoted with org1 and org2. const diplomas =
The system was developed in two stages – Stage 1 [ consists of using an isolated GIT branch of the HEIs to add { a functionality to export diploma supplemental materials "name": "Firstname", as an API to the blockchain network. Stage 2 comprised "surname": "Surname", of developing a lightweight blockchain application, based "studygroup": "StudyGroup", on Hyperledger Fabric, to connect the the API and add "grades": the data to a block. The architecture of the two-stage [ system is shown in Fig. 2. {
The main parameter which Hyperledger Fabric uses "grade": "GradeValue", is the transaction context ctx. It holds the needed in- "course": "CourseCode", formation for transaction logic "per transaction" or "per }, contract". IT enables to access the stub which allows var- ... ious blockchain operations such as state returns, adding ] a new item to the block, or getting all blocks (in our case } diploma supplements). ...
To add a diploma supplement, it is needed to connect ] toe the peer node using a gateway, and to get the chaincode from the network. When data is added, a message can be viewed in the
To write the transaction i.e. diploma object, an asyn- console terminal to confirm a successful transaction, as chronous promise function will get all the necessary shown in Fig. 4. In our testbed, and endpoint was not parameters for add a new diploma supplement, as shown deployed from the IS’s side; therefore we have manually in Fig. 3. It will create a new object with those param- added the data in the same format as the HEI’s IS would eters which will be later added to teh blockchain using provide. stub API operations.
The data which is added to the blockchain has the following structure:
In this paper, we have used Hyperledger Fabric to de- This paper was supported by the Blockchain Technolvelop a lightweight blockchain network for credentialing ogy Laboratory at Belgrade Metropolitan University, BelHEI’s diplomas and diploma supplements. Currently, grade, Serbia. our system only addresses the issuance use-case, while validation use-case remains open. As prototyping was conducted in an isolated environment, several open is- References sues still remain. Firstly, should the blockchain remain private, or be public (where anyone can be a part of the network)? As the target group of the system are first and foremost HEIs, the authors, as was discussed in other literature as well, opt for a private blockchain solution, where the HEIs comprise the network. Still, there exists a possibility to add the learners as nodes as well.
Using Hyperledger Fabric, data such as diplomas and supplements can be issued and verified reliably.
Blockchain can help learning platforms to add an additional layer to their credentialing process. We have presented a blockchain-based credentialing system can be easily deployable and connected to a learning platform. Within our proposed system, upon generating the certificate file for the diploma and/or supplement, the HEI’s IS will make a transaction to the blockchain. This entry will also have the certificate information, alongside metadata required for the transaction header. This information will be encrypted, and can be accessed only by the IS, the student, and an authorized third party.
This new issuance transaction is sent to the blockchain, where the other nodes in the network will verify it and add it to the blockchain using a simpler consensus mechanism. Each node will have a local copy of the blockchain on a NoSQL database like CouchDB. For certificate validation, upon receiving the access link, the student or an authorized third party can verify the digital credential by accessing the blockchain through a query. If a match is found on the blockchain, the certificate file is validated and a corresponding message appears.
The innate immutability property of BCT/DLT does not allow fraudulent or modified certificate files to be deemed as verified. Any tampering to the certificate file will result in a vastly diferent hashed value of the file, ensuring impossible verification.