"A certificate authority or certification authority (CA) is an entity that stores, signs, and issues digital certificates."
An entity that issues digital certificates for use in electronic transactions.
Cryptography basics: Cryptography is a technique used to secure communication and protect information from unauthorized access or modification. A good understanding of encryption, decryption, digital signatures, hash functions, and other cryptographic concepts is necessary to learn about CAs.
Public key infrastructure (PKI): PKI is a system of public key cryptography that ensures secure communication over a network. It relies on digital certificates issued by CAs to establish trust between communicating parties.
Certificate lifecycle management: The lifecycle of a certificate includes its creation, issuance, revocation, and expiry. CAs are responsible for managing this lifecycle and ensuring the validity and trustworthiness of certificates.
Types of certificates: There are different types of certificates such as root, intermediate, and end-entity certificates. Each type of certificate has a different purpose and requirements.
Certificate signing: CAs sign certificates to establish trust and verify the authenticity of information. Signing involves using the CA's private key to add a digital signature to the certificate.
Certificate validation: Certificate validation is the process of verifying the authenticity and validity of a certificate. This involves checking the certificate's digital signature, expiration date, and revocation status.
Certificate revocation: Certificates can be revoked if they are compromised or no longer valid. CAs must maintain a Certificate Revocation List (CRL) to track revoked certificates.
Trust hierarchy: CAs operate in a hierarchical structure with root CAs at the top, followed by intermediate CAs, and end-entity certificates. Understanding the trust hierarchy is crucial to establish trust between parties.
Security protocols: CAs must adhere to security protocols such as SSL/TLS, IPSec, and S/MIME to ensure secure communication and prevent attacks such as man-in-the-middle attacks and phishing attacks.
Compliance and regulations: CAs must adhere to various compliance regulations such as GDPR, HIPAA, and PCI DSS to ensure the confidentiality, integrity, and availability of information.
Key management: A good understanding of key management processes such as key generation, distribution, and storage is necessary for secure certificate management.
Certificate transparency: Certificate transparency is a public log of certificates issued by CAs. It provides transparency into CA operations and helps detect fraudulent certificates.
Public CAs: These are third-party organizations that issue certificates to individuals or organizations. They verify the authenticity of the identity of the certificate holder before issuing a certificate.
Private CAs: These CAs are owned by organizations and issue certificates to their employees or devices within their network. They have control over the verification process and issue certificates based on their own policies and procedures.
Enterprise CAs: These are private CAs that are deployed in large organizations and provide centralized management of certificates issued to employees, devices or servers.
Root CAs: These are at the top of the certificate hierarchy and issue certificates to intermediate CAs. They are highly trusted and their certificates are embedded in browsers and operating systems.
Intermediate CAs: These are CAs that are issued certificates by root CAs and issue certificates to end-users or subordinate CAs. They act as an intermediary between root CAs and end-users.
Domain Validated CAs: These CAs check the ownership of the domain name associated with the certificate request by sending an email to the email address specified in the certificate request.
Organization Validated CAs: These CAs verify the identity and address of the organization associated with the certificate request.
Extended Validation CAs: These CAs provide additional verification steps, such as checking legal documentation, physical location, and telephone verification to validate the identity of the certificate holder.
Code Signing CAs: These CAs provide certificates for code signing, which verifies the authenticity and integrity of software code.
Time Stamp CAs: These CAs provide certificates that validate the date and time of digital documents or transactions by providing a trusted timestamp that is attached to the document.
"A digital certificate certifies the ownership of a public key by the named subject of the certificate."
"This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key."
"A CA acts as a trusted third party—trusted both by the subject (owner) of the certificate and by the party relying upon the certificate."
"The format of these certificates is specified by the X.509 or EMV standard."
"One particularly common use for certificate authorities is to sign certificates used in HTTPS, the secure browsing protocol for the World Wide Web."
"Another common use is in issuing identity cards by national governments for use in electronically signing documents."
"An entity that stores, signs, and issues digital certificates."
"Others (relying parties) can rely upon signatures... made about the private key that corresponds to the certified public key."
"A public key by the named subject of the certificate."
"Certificates used in HTTPS, the secure browsing protocol for the World Wide Web."
"The format of these certificates is specified by the X.509 or EMV standard."
"Issuing identity cards by national governments for use in electronically signing documents."
"An entity that... issues digital certificates."
"Assertions made about the private key that corresponds to the certified public key."
"A CA acts as a trusted third party—trusted both by the subject (owner) of the certificate."
"Rely upon signatures... made about the private key that corresponds to the certified public key."
"The format of these certificates is specified by the X.509 or EMV standard."
"Sign certificates used in HTTPS, the secure browsing protocol for the World Wide Web."
"Issuing identity cards by national governments for use in electronically signing documents."