By Victor Cruzat, Information Security Analyst, TraceSecurity
Cybersecurity depends on trust to ensure user data is secure and confidential both in transit and on the user’s workstation. Without trust, the internet would pose severe security risks to businesses, governments, and individuals. According to Okta, “Public key infrastructure uses asymmetric encryption methods to ensure that messages remain private and to authenticate the device or user sending the transmission.”1 Certificate Authorities and the Chain of Trust are the backbone of entity validation. Grasping this concept is essential when looking to gain a deeper understanding of how user identity authentication works. This knowledge is critical for defending networks against threats like phishing and man-in-the-middle (MITM) attacks, and security risks that may compromise businesses or systems.
SSL support Team writes, “certificate authority is a company or organization that acts to validate the identities of entities (such as websites, email addresses, companies, or individual persons) and bind them to cryptographic keys through the issuance of electronic documents known as digital certificates.”2 Certificate Authorities (CA) are the backbone of PKI because CAs validate the identities of entities before issuing certificates. This digital certificate, which is issued, prevents attackers from obtaining fraudulent certificates. Once validated, a CA signs the certificate, which browsers and systems can trust as authentic. In a security context, this makes CAs gatekeepers who safeguard the legitimacy of encrypted communications across the internet. This process is like an employee showing their ID badge at work: once verified, security grants them access.
The Chain of Trust is structured hierarchically to ensure resilience. Debbie Hayes of Globalsign explains, “This idea is essential for how digital certificates and Public Key Infrastructure (PKI) work, ensuring that people and devices can communicate safely.”3 Root CAs issue certificates to end entities such as websites. By delegating authority through intermediate CAs, organizations reduce the risk of exposing root keys, which must remain highly protected. This structure embodies the principle of defense-in-depth, a core cybersecurity strategy. This end entity is known as the “leaf” in the chain of trust, where the end entity proves an identity or secures communication. A Root CA is the initial authority that confirms an identity, intermediate CAs are the middle managers that delegate trust, and end entities are the actual people, servers, or devices that need to prove who they are.
Each time a browser connects to a secure website, it performs validation of the certificate chain. Keyfactor notes, “The Chain of Trust Certification aims to prove that a particular certificate originates from a trusted source.”4 Keyfactor adds, “The SSL/TLS internet security standard is based on a trust relationship model, also called ‘certificate chain of trust.’”4 When a browser connects to a secure website, it validates the certificate chain by checking its source, confirming expiration dates, and consulting revocation systems like OCSP and CRLs. This automated process operates as a defensive mechanism, blocking users from connecting to potentially malicious or tampered sites. Malicious sites often do not carry the proper certifications to bypass this protocol.
Threats and Security Implications & Mitigation
Cyber adversaries frequently attempt to exploit weaknesses in certificate management or CA operations. Encryption Consulting emphasizes that “If any certificate fails the validation process, the chain of trust is broken.”5 Encryption Consulting adds, “Certificates can be revoked for various reasons, such as compromise or suspicion of fraudulent activity.”5 Essentially, this is a checks-and-balances system that verifies end users at each step of the data transmission process by utilizing an intermediary mediator. This warning system protects against spoofed websites and MITM attacks. For enterprises, poor PKI management can result in expired certificates causing outages or even attackers leveraging misconfigurations for access. Enterprises with expired or mismanaged certificates are vulnerable to traffic interception, decryption, and session hijacking. Strong governance, lifecycle monitoring, and compliance with industry cryptographic standards are necessary to preserve trust in the chain. To prevent this vulnerability, enterprises must ensure that their website’s certificate meets security standards and is not expired, self-signed, or expiring too far in the future. Effective PKI governance reduces these risks by ensuring certificates remain valid, properly configured, and compliant with industry standards.
In the cybersecurity landscape, the chain of trust is not simply a technical mechanism. Chain of Trust is a defense system that underpins the safety of digital communications. Certificate Authorities validate identities, the chain of trust structures security hierarchically, and validation processes act as a first line of defense against attackers. Trust is the foundation of security, and Certificate Authorities provide the trust that makes secure online communication possible. To maintain that trust, organizations must continuously audit, monitor, and strengthen PKI practices against evolving threats. End-to-end security is greatly preserved by an organization’s ability to meet PKI compliance requirements. Maintaining PKI compliance and strong certificate management is not optional; it is essential for safeguarding modern digital infrastructure.
Connect with TraceSecurity to learn more.
References:
1. Okta. February 23, 2025. What is Public Key Infrastructure and How Does it Work?
2. SSL Support Team. SSL.com. January 5, 2024. What is a Certificate Authority?
3. Globalsign. Debbie Hayes. August 08, 2024. What is the Chain of Trust? Key Concepts and Applications.
4. KeyFactor. Toby Gaff. September 2, 2020. What is the Certificate Chain of Trust.
5. Encryption Consulting. Surabhi Dahal. September 18, 2023. What is Certificate Chain of Trust, and how does it work?