What is a Certificate Authority (CA)?
A certificate authority (CA) is a trusted entity that issues digital certificates to authenticate content sent from web servers. These certificates are data files used to cryptographically link an entity with a public key.
Web browsers use these certificates to authenticate content sent from web servers, ensuring trust in content delivered online and facilitating more trustworthy online transactions. The main goal of a CA is to verify the authenticity and trustworthiness of a website, domain, and organization so users know exactly who they're communicating with online and whether that entity can be trusted with their data.
The Purpose of a Certificate Authority
A CA's primary purpose is to validate an entity's identity. When a CA issues a digital certificate for a website, company, or individual, it verifies the entity's credentials and binds them to cryptographic keys that prove the entity's identity. This establishes the entity as trustworthy and allows them to engage in encrypted and secure communications with other entities.
When users access a website using an HTTPS connection, their browser checks the digital certificate issued by the CA against its own root certificate store. If the certificate is valid, the user can trust that the communication is secure and encrypted. If the certificate is invalid or untrusted, the browser may display warning messages or prevent the transaction from occurring.
The Role of a CA in the Chain of Trust
A CA plays a vital role in maintaining the chain of trust, which is a hierarchical trust model that consists of root certificates, intermediate certificates, and SSL certificates. The CA starts with a root certificate, which serves as the ultimate basis for trust in all certificates issued by the authority.
The root certificate is treated with the highest level of security and is usually stored offline in a protected facility or on a device that is unpowered except when the certificate is needed. The CA uses this root certificate to create intermediate certificates, which support different purposes and enable the public to trust the issued certificates while protecting the root certificate.
Types of Certificates Issued by a CA
A CA can issue various types of certificates for different use cases, including:
- TLS certificates: Used for secure encrypted connections over the internet via web browsers that connect to websites.
- Code-signing certificates: Used to authenticate software and ensure its integrity.
- S/MIME certificates: Used for secure email communication and encryption.
The CA/Browser Forum is a group of CAs and digital certificate consumers that maintains guidelines for all aspects of creating, distributing, and using digital certificates. All active participants of the forum must agree with its Intellectual Property Rights (IPR) policy and comply with all its bylaws, including its code of conduct and antitrust laws and regulations.
Safeguarding Online Communications
Safeguarding the authenticity of online communications is essential to running a business. By using public and private keys in digital signatures, managing electronic documents, and exploring types of PKI certificates and their use cases, individuals can ensure that their online transactions are secure and trustworthy.