## 1 Introduction
The registrar's office sends the signed diplomas to the office of the actor of the university. 7. The head of the university signs the diplomas and returns them to the registrar's office. 8. Students are awarded diplomas at a graduation ceremony. The workflow for the registration of the academic mobility of students or for transferring to another university is as follows:  
1. A student applies to transfer to another university or to register for academic mobility. 2. The faculty and the registrar's office prepare an academic transcript of the student with a complete history of academic performance. 3. The head (the dean, vice-rector or rector--the university determines which one independently) and the registrar's office sign the transcript. 4. The registrar's office sends the transcript to the student. Based on this description of the steps required in the document issuance process, it is easy to understand why problems may arise in the paper document flow, i.e., there is the possibility of technical error, fraud with the help of an unscrupulous employee and forgery of signatures. Therefore, to ensure the protection and integrity of data, blockchain technology is the best solution. The purpose of this research is to develop and test a platform based on Ethereum technology for storing and verifying information about student academic performance. Maintaining the confidentiality of documents allows students to create a permanent public record, to be protected from changes in the educational institution or from loss of personal data, to share it with employers and to monitor the level of their own academic achievements [10]. This paper is a continuation of our research on the use of blockchain technologies in education. Earlier, the architecture of the platform based on a globally distributed peer-to-peer network was presented; this allows for student registration and the authentication of educational documents [11]. During practical implementation of the platform, we realized that only a small number of papers evaluate the performance of blockchain solutions. Most relevant research papers are devoted to general blockchain problems, such as decentralization, transparency, security and data immutability. We define these criteria as theory-based solutions. Only a small number of papers present results on important factors such as time, data storage and transaction costs; these are considered the main computing resources. We define these characteristics as practicality based. Based on the relevant scientific literature, the following results were obtained:  
1. Characteristic problems associated with the functioning of blockchain systems used in the field of education were identified. 2. The architecture of the UniverCert blockchain system proposed in previous work was improved. 3. Two evaluation criteria were formulated: 1. Compliance of the developed prototype with the theoretical aspects of blockchain systems. 2. Compliance of the developed prototype with performance requirements. 4. A working prototype of the UniverCert blockchain system was developed. This paper presents the UniverCert platform for higher education institutions, developed based on the hybrid architecture of the Ethereum blockchain, which allows for the creation of a single digital register of official documents with the ability to integrate data provided from external university platforms. Transcripts indicating academic achievements for each semester and a diploma for higher/postgraduate education are considered official documents of the learning process. The platform provides verification services for these documents for third-party organizations. This paper offers practical solutions in terms of time, latency and data storage; the theoretical analysis is supported by experimental results. This paper proceeds as follows. Section 2 introduces related work in terms of three key aspects: time consumption, data storage and cost per transaction. Section 3 introduces the architecture of the UniverCert platform.