## 4 SECHash Proof-of-Concept
### Technology Selection  
To implement the SECHash system model, the following technologies and components were selected considering several factors: the learning curve of the chosen technologies, local market, hardware, cost, performance, maintainability, stability, and security. * _Django Web framework_[42]. It is an open-source web application framework written in Python. Because of its rapid development capabilities, Django is very sophisticated in today's market; it takes less time to build any application. It uses the Model View Template (MVT) design structure. Its name comes from the framework based on the model as the database, the view as the control function, and the templates as the user pages for communication interactions. A Django model acts as a database manager and uses two main commands: 1. Django picks up the changes in the models.py file after python manage.py performs the migrations and sends the data to the PostgreSQL database, then migrate python manage.py. The Django system then saves all changes to the database system. 2. Python manage.py runs the server at the end. This will start the project and give the user the local host address of the project running locally. The views.py file also handles project requests into template management API calls within demands. The user can describe her/his views using Python functions [42]. * _PostgreSQL database technology_[43]. It supports most SQL transactions and provides concurrency control. In addition, it offers modern features such as complex queries, triggers, views, transnational integrity, and allows adding data type extensions. It also provides functions, operators, and procedural languages. As a result, it is one of the world's most advanced open-source Database Management Systems (DBMS) [43]. * _LBRY_ ([[https://spec.lbry.com/](https://spec.lbry.com/)]([https://spec.lbry.com/](https://spec.lbry.com/)), accessed on 14 April 2023). A protocol enables a decentralised online content marketplace. Specifically, it uses blockchain to build a community controlled decentralised content platform. That lets users quickly publish,  
Figure 3: State diagram for bill document. Figure 2: Sequence diagram for the system model. host, search, access, download, and pay for content. LBRY introduces a new naming scheme that gives users complete control over the name of their content and uses blockchain to create a digital currency (LBC), a transparent distributed ledger, and a sync for all users. A global index of content metadata that also supports access to a unique namespace and supports new paradigms in digital content delivery [44]. The LBRY credits specifications are as follows: - Max Supply: 1,083,202,000 LBC. - Coin Type: PoW. - PoW Algorithm: lbry. - PoW Period: 20 years. - Block Time: 2.5 min. - Current Block Reward: 345 LBC. - Premine: 400,000,000 LBC. * _Hash function_. An algorithm takes user data as input and produces a fixed-length output (called a hash digest) for the input data. Federal Information Processing Standard (FIPS) 180-44 ([PERSON], 2015) [45] provided distinct requirements for hash functions algorithms certified by the National Institute of Standards and Technology (NIST). As a result, the Secure Hash Algorithms (SHA) family are the most commonly implemented hash function in different applications [46]. LBRY is a PoW algorithm that combines SHA-256, SHA-512, and RIPEMD hash functions. This algorithm enables fast and secure transactions on the LBRY network. 1. SHA-256 has an output of 32 bytes and is displayed as a 64-character hexadecimal string. Therefore, it is considered secure and fast. The most common uses of SHA-256 are website authentication, digital signature, blockchain security, and file and fingerprint comparison in antivirus programs [47]. 2. SHA-512 is an algorithm based on non-linear functions that output 64 bytes. It is designed to prevent any cracking method and is unbreakable. At the same time, the user data are encrypted by hashing it to 128-bit hexadecimal characters.