Please answer the following question: Information: - In cryptography, X.509 is an important standard for a public key infrastructure (PKI) to manage digital certificates and public-key encryption and a key part of the Transport Layer Security protocol used to secure web and email communication. An ITU-T standard, X.509 specifies formats for public key certificates, certificate revocation lists, attribute certificates, and a certification path validation algorithm. - Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), both frequently referred to as "SSL", are cryptographic protocols that provide communications security over a computer network. Several versions of the protocols find widespread use in applications such as web browsing, email, Internet faxing, instant messaging, and voice-over-IP (VoIP). Websites use TLS to secure all communications between their servers and web browsers. - The certification path validation algorithm is the algorithm which verifies that a given certificate path is valid under a given public key infrastructure (PKI). A path starts with the Subject certificate and proceeds through a number of intermediate certificates up to a trusted root certificate, typically issued by a trusted certificate authority (CA). - The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU); it coordinates standards for telecommunications. - A public key infrastructure (PKI) is a set of roles, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilitate the secure electronic transfer of information for a range of network activities such as e-commerce, internet banking and confidential email. It is required for activities where simple passwords are an inadequate authentication method and more rigorous proof is required to confirm the identity of the parties involved in the communication and to validate the information being transferred. - Cryptography or cryptology (from Greek "kryptos", "hidden, secret"; and "graphein", "writing", or "-logia", "study", respectively) is the practice and study of techniques for secure communication in the presence of third parties called adversaries. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages; various aspects in information security such as data confidentiality, data integrity, authentication, and non-repudiation are central to modern cryptography. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, and electrical engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce. - In cryptography, a certificate authority or certification authority (CA) is an entity that issues digital certificates. 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. In this model of trust relationships, a CA is a trusted third partytrusted both by the subject (owner) of the certificate and by the party relying upon the certificate. The most commonly encountered public-key infrastructure (PKI) schemes are those used to implement https on the world-wide web. All these are based upon the X.509 standard and feature CAs. - DigiCert Inc is a privately held , US based X.509 SSL certificate provider . As a trusted third party , DigiCert verifies the authenticity of secure websites on behalf of a web browser for the purpose of preventing online phishing scams . As a founding member of the CA / Browser Forum , the group that sets industry standards for publicly trusted digital certificates , DigiCert assisted in the development of the Extended Validation Certificate , which provides enhanced identity verification of certificate holders . DigiCert also worked in conjunction with Microsoft to develop and promote the use of subject alternate names in SSL certificates , for use with Microsoft Exchange Server . DigiCert is the largest public CA that does not issue '' domain validated '' , '' low assurance '' , or '' instant '' SSL certificates either directly or through a subsidiary brand . It primarily sells Organization Validation ( OV ) and Enhanced Validation ( EV ) SSL certificates . DigiCert Inc. is of no relation to Digicert Sdn . Bhd , a Malaysian - based certification authority that issues certificates with weak keys and had its trust revoked by web browsers . - In cryptography, a trusted third party (TTP) is an entity which facilitates interactions between two parties who both trust the third party; the Third Party reviews all critical transaction communications between the parties, based on the ease of creating fraudulent digital content. In TTP models, the relying parties use this trust to secure their own interactions. TTPs are common in any number of commercial transactions and in cryptographic digital transactions as well as cryptographic protocols, for example, a certificate authority (CA) would issue a digital identity certificate to one of the two parties in the next example. The CA then becomes the Trusted-Third-Party to that certificates issuance. Likewise transactions that need a third party recordation would also need a third-party repository service of some kind or another. - In cryptography, a public key certificate (also known as a digital certificate or identity certificate) is an electronic document used to prove the ownership of a public key. The certificate includes information about the key, information about its owner's identity, and the digital signature of an entity that has verified the certificate's contents are correct. If the signature is valid, and the person examining the certificate trusts the signer, then they know they can use that key to communicate with its owner. What entity does 'digicert' has the relation 'instance of' with?
Answer:
certificate authority