# Blockchain-Based Evidence Trustworthiness System in Certification
## 1 Introduction  
Certifications have become increasingly important as a formal recognition of specific characteristics, skills, or knowledge [1]. They are a proof that some regulations or standards have been met and the necessary competencies are possessed, achieving a commitment to quality and excellence. For organizations, certifications can generally enhance customer confidence and satisfaction [2]; they are more likely to trust and choose certified products and services, knowing that they meet high standards of quality and safety. That is why the number of certifications has greatly increased in recent years. For example, the International Organization for Standardization (ISO) has presented a survey [3] in which the number of ISO-based issued certifications is presented for 2023. Auditors play a critical role in certification processes by ensuring that organizations comply with specific standards and regulations. One of their primary tasks is to assess the effectiveness of organization systems based on various evidence. Evidence is essential for certification for the following reasons [4, 5]:  
* Evidence offers solid confirmation that an entity complies with the specific requirements of a regulation or standard. This verification is essential to ensure that the certification is grounded in factual and precise information. * The presentation of evidence fosters trust and credibility among stakeholders, such as auditors, regulators, or even customers. It demonstrates that a given certification is more than a formality, being supported by verifiable data. * Evidence guarantees transparency in any certification process, enabling all involved parties to understand the foundation upon which the certification was awarded, fostering openness and accountability. Evidence is essential during audits and reviews to demonstrate compliance with standards. It helps auditors verify that processes and practices comply with the required criteria. * In numerous industries, presenting evidence is a legal requirement to ensure that organizations adhere to all pertinent laws and regulations. * Evidence-based certification eliminates subjectivity from the process. Decisions are grounded in objective data rather than opinions, ensuring both fairness and consistency. In conclusion, evidence is crucial in a certification process as it provides the essential proof that specific requirements have been met. This includes documentation, records, test results, and other forms of verification that confirm compliance with the certification criteria. Without robust evidence, validating the authenticity and reliability of the certification would be difficult. However, nowadays, evidence refers to digital evidence. which raises a number of security issues that need to be addressed [6,7]:  
* Digital evidence is particularly vulnerable to tampering, and any unauthorized modifications can undermine its integrity. * Inherent volatility in digital evidence means that mishandling during collection, storage, or transfer can lead to data loss or corruption. * Maintaining the long-term integrity of digital evidence is complex. Conventional storage solutions often fail to prevent data degradation and loss over time. To mitigate these risks, it is crucial to follow strict protocols for the management, storage, and transfer of digital evidence. Thus, auditors are increasingly demanding digital audit trail systems as security measures to improve the integrity, traceability, and accessibility of crucial information related to the certification process, such as evidence [8]. At the same time, these systems streamline certification processes, simplifying auditing and saving time and effort. Thus, they play a crucial role in a certification process, as they result in greater acceptance and credibility for the certified entity. This work analyses the main security risks of evidence for a certification process and presents how an already existing audit trail solution based on Blockchain technology can be adjusted to guarantee evidence trustworthiness.