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Glossary of PKI Terms

Affiliate: A corporation, partnership, joint venture or other entity controlling, controlled by, or under common control with another entity, or an agency, department, political subdivision, or any entity operating under the direct control of a Government Entity.

American Institute of Certified Public Accountants (AICPA): AICPA is the national professional organization of Certified Public Accountants (CPAs) in the United States. It defines ethical standards for the profession and U.S. auditing standards for audits of private companies, non-profit organizations, federal, state and local governments.

Applicant: The natural person or Legal Entity that applies for (or seeks renewal of) a Certificate. Once the Certificate issues, the Applicant is referred to as the Subscriber. For Certificates issued to devices, the Applicant is the entity that controls or operates the device named in the Certificate, even if the device is sending the actual certificate request.

Applicant Representative: A natural person or human sponsor who is either the Applicant, employed by the Applicant, or an authorized agent who has express authority to represent the Applicant: (i) who signs and submits, or approves a certificate request on behalf of the Applicant, and/or (ii) who signs and submits a Subscriber Agreement on behalf of the Applicant, and/or (iii) who acknowledges the Terms of Use on behalf of the Applicant when the Applicant is an Affiliate of the CA or is the CA.

Application Software Supplier: A supplier of Internet browser software or other relying-party application software that displays or uses Certificates and incorporates Root Certificates.

Attestation Letter: A letter attesting that Subject Information is correctly written by an accountant, lawyer, government official, or other reliable third party customarily relied upon for such information.

Audit Period: In a period-of-time audit, the period between the first day (start) and the last day of operations (end) covered by the auditors in their engagement. (This is not the same as the period of time when the auditors are on-site at the CA.)

Audit Report: A report from a Qualified Auditor stating the Qualified Auditor’s opinion on whether an entity’s processes and controls comply with the mandatory provisions of these Requirements.

Authorization Domain Name: The Domain Name used to obtain authorization for certificate issuance for a given FQDN. The CA may use the FQDN returned from a DNS CNAME lookup as the FQDN for the purposes of domain validation. If the FQDN contains a wildcard character, then the CA MUST remove all wildcard labels from the left-most portion of requested FQDN. The CA may prune zero or more labels from left to right until encountering a Base Domain Name and may use any one of the intermediate values for the purpose of domain validation.

Authorized Ports: One of the following ports: 80 (http), 443 (http), 25 (smtp), 22 (ssh).

Base Domain Name: The portion of an applied-for FQDN that is the first domain name node left of a registry-controlled or public suffix plus the registry-controlled or public suffix (e.g. “example.co.uk” or “example.com”). For FQDNs where the right-most domain name node is a gTLD having ICANN Specification 13 in its registry agreement, the gTLD itself may be used as the Base Domain Name.

Canadian Institute of Chartered Accountants (CICA): CICA is an organization that develops and maintains accounting, auditing and assurance standards for financial organizations in Canada. It has also issued the professional designation of Chartered Accountant.

Certificate: An electronic document that uses a digital signature to bind a public key and an identity.

Certificate Data: Certificate requests and data related thereto (whether obtained from the Applicant or otherwise) in the CA’s possession or control or to which the CA has access.

Certificate Management Process: Processes, practices, and procedures associated with the use of keys, software, and hardware, by which the CA verifies Certificate Data, issues Certificates, maintains a Repository, and revokes Certificates.

Certificate Policy (CP): A set of rules that indicates the applicability of a named Certificate to a particular community and/or PKI implementation with common security requirements.

Certificate Problem Report: Complaint of suspected Key Compromise, Certificate misuse, or other types of fraud, compromise, misuse, or inappropriate conduct related to Certificates.

Certificate Revocation List (CRL): A regularly updated time-stamped list of revoked Certificates that is created and digitally signed by the CA that issued the Certificates.

Certification Authority (CA): An organization that is responsible for the creation, issuance, revocation, and management of Certificates. The term applies equally to both Roots CAs and Subordinate CAs.

Certification Authority Authorization (CAA): RFC 6844 states that “The Certification Authority Authorization (CAA) DNS Resource Record allows a DNS domain name holder to specify the Certification Authorities (CAs) authorized to issue certificates for that domain. Publication of CAA Resource Records allows a public Certification Authority to implement additional controls to reduce the risk of unintended certificate mis-issue.”

Certification Practice Statement (CPS): One of several documents forming the governance framework in which Certificates are created, issued, managed, and used.

Control: “Control” (and its correlative meanings, “controlled by” and “under common control with”) means possession, directly or indirectly, of the power to: (1) direct the management, personnel, finances, or plans of such entity; (2) control the election of a majority of the directors; or (3) vote that portion of voting shares required for “control” under the law of the entity’s Jurisdiction of Incorporation or Registration but in no case less than 10%.

Country: Either a member of the United Nations OR a geographic region recognized as a Sovereign State by at least two UN member nations.

Country Code Top-Level Domain (ccTLD): A ccTLD is an Internet top-level domain generally used or reserved for a country, sovereign state, or dependent territory identified with a country code.

Cross Certificate: A certificate that is used to establish a trust relationship between two Root CAs.

Cryptographically Secure Pseudo-Random Number Generator (CSPRNG): A random number generator intended for use in cryptographic system.

Delegated Third Party: A natural person or Legal Entity that is not the CA, and whose activities are not within the scope of the appropriate CA audits, but is authorized by the CA to assist in the Certificate Management Process by performing or fulfilling one or more of the CA requirements found herein.

Domain Authorization Document: Documentation provided by, or a CA’s documentation of a communication with, a Domain Name Registrar, the Domain Name Registrant, or the person or entity listed in WHOIS as the Domain Name Registrant (including any private, anonymous, or proxy registration service) attesting to the authority of an Applicant to request a Certificate for a specific Domain Namespace.

Domain Contact: The Domain Name Registrant, technical contact, or administrative contract (or the equivalent under a ccTLD) as listed in the WHOIS record of the Base Domain Name or in a DNS SOA record, or as obtained through direct contact with the Domain Name Registrar.

Domain Name: The label assigned to a node in the Domain Name System.

Domain Name Registrant: Sometimes referred to as the “owner” of a Domain Name, but more properly the person(s) or entity(ies) registered with a Domain Name Registrar as having the right to control how a Domain Name is used, such as the natural person or Legal Entity that is listed as the “Registrant” by WHOIS or the Domain Name Registrar.

Domain Name Registrar: A person or entity that registers Domain Names under the auspices of or by agreement with: (i) the Internet Corporation for Assigned Names and Numbers (ICANN), (ii) a national Domain Name authority/registry, or (iii) a Network Information Center (including their affiliates, contractors, delegates, successors, or assigns).

Domain Name System (DNS): DNS is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private network. It associates domain names with a numerical IP address for locating and identifying electronic devices within the underlying network protocols. By providing a worldwide directory service, the Domain Name System is an essential component of the Internet since 1985.

Domain Namespace: The set of all possible Domain Names that are subordinate to a single node in the Domain Name System.

Enterprise RA: An employee or agent of an organization unaffiliated with the CA who authorizes issuance of Certificates to that organization.

Expiry Date: The “Not After” date in a Certificate that defines the end of a Certificate’s validity period.

Federal Information Processing Standards (FIPS): FIPS are public standards developed by the United States federal government for use in computer systems by non-military government agencies and government contractors. FIPS are issued to establish operational requirements for achieving adequate computer and data security.

Fully Qualified Domain Name (FQDN): A Domain Name that includes the labels of all superior nodes in the Internet Domain Name System.

Government Entity: A government-operated legal entity, agency, department, ministry, branch, or similar element of the government of a country, or political subdivision within such country (such as a state, province, city, county, etc.).

Health Insurance Portability and Accountability Act (HIPAA): Enacted by the US Congress in 1996, HIPAA establishes national standards for electronic transactions with protected health information.

High Risk Certificate Request: A Request that the CA flags for additional scrutiny by reference to internal criteria and databases maintained by the CA, which may include names at higher risk for phishing or other fraudulent usage, names contained in previously rejected certificate requests or revoked Certificates, names listed on the Miller Smiles phishing list or the Google Safe Browsing list, or names that the CA identifies using its own risk-mitigation criteria.

Internal Name: A string of characters (not an IP address) in a Common Name or Subject Alternative Name field of a Certificate that cannot be verified as globally unique within the public DNS at the time of certificate issuance because it does not end with a Top Level Domain registered in IANA’s Root Zone Database.

International Organization for Standardization (ISO): ISO is an independent, non-governmental international organization with the goal of developing international Standards. ISO has a membership of 161 national standards bodies.

Internet Assigned Numbers Authority (IANA): IANA is a standard role for an entity managing the global coordination of the DNS Root, IP addressing, and other Internet protocol resources. Currently this role is filled by ICANN.

Internet Corporation for Assigned Names and Numbers (ICANN): ICANN is a non-profit private American corporation, responsible for coordinating the Internet Assigned Numbers Authority functions. These functions include maintaining the Central Adress pools and the DNS root zone registries.

Internet Engineering Task Force (IETF): The Internet Engineering Task Force is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet.

Issuing CA: In relation to a particular Certificate, the CA that issued the Certificate. This could be either a Root CA or a Subordinate CA.

Key Compromise: A Private Key is said to be compromised if its value has been disclosed to an unauthorized person, an unauthorized person has had access to it, or there exists a practical technique by which an unauthorized person may discover its value. A Private Key is also considered compromised if methods have been developed that can easily calculate it based on the Public Key (such as a Debian weak key, see http://wiki.debian.org/SSLkeys) or if there is clear evidence that the specific method used to generate the Private Key was flawed.

Key Generation Script: A documented plan of procedures for the generation of a CA Key Pair.

Key Pair: The Private Key and its associated Public Key.

Legal Entity: An association, corporation, partnership, proprietorship, trust, government entity or other entity with legal standing in a country’s legal system.

National Institute of Standards and Technology (NIST): NIST is a physical sciences laboratory, and a non-regulatory agency of the United States Department of Commerce, aiming to promote innovation and industrial competitiveness in ways that enhance economic security. NIST maintains a data security standard followed by all government web sites.

OCSP Responder: An online server operated under the authority of the CA and connected to its Repository for processing Certificate status requests. See also, Online Certificate Status Protocol.

Object Identifier (OID): A unique alphanumeric or numeric identifier registered under the International Organization for Standardization’s applicable standard for a specific object or object class.

Online Certificate Status Protocol (OCSP): An online Certificate-checking protocol that enables relying-party application software to determine the status of an identified Certificate. See also OCSP Responder.

PCI Data Security Standard (DSS): PCI DSS is a standard document providing a baseline of technical and operational requirements designed to protect account information. PCI DSS applies to all entities involved in payment card processing-including merchants, processors, acquirers, issuers, and service providers.

PCI Standards Security Council (SSC): The PCI Security Standards Council is a global forum for the ongoing development, enhancement, storage, dissemination and implementation of security standards for account data protection. PCI SSC is the managing body of the PCI Data Security Standard document.

Parent Company: A company that Controls a Subsidiary Company.

Payment Card Industry (PCI): PCI refers to the debit, credit, prepaid, e-purse, ATM, and POS cards and associated businesses.

Private Key: The key of a Key Pair that is kept secret by the holder of the Key Pair, and that is used to create Digital Signatures and/or to decrypt electronic records or files that were encrypted with the corresponding Public Key.

Protected Health Information (PHI): Under US Law, PHI is any information about health status, provision of health care, or payment for health care that can be linked to a specific individual.

Public Key: The key of a Key Pair that may be publicly disclosed by the holder of the corresponding Private Key and that is used by a Relying Party to verify Digital Signatures created with the holder’s corresponding Private Key and/or to encrypt messages so that they can be decrypted only with the holder’s corresponding Private Key.

Public Key Infrastructure (PKI): A set of hardware, software, people, procedures, rules, policies, and obligations used to facilitate the trustworthy creation, issuance, management, and use of Certificates and keys based on Public Key Cryptography.

Publicly Trusted Certificate: A Certificate that is trusted by virtue of the fact that its corresponding Root Certificate is distributed as a trust anchor in widely available application software.

Qualified Auditor: A natural person or Legal Entity that meets the requirements of Section 8.2 of the CA/Browser Forum Baseline Requirements for the Issuance and Management of Publicly-Trusted Certificates.

Random Value: A value specified by a CA to the Applicant that exhibits at least 112 bits of entropy.

Registered Domain Name: A Domain Name that has been registered with a Domain Name Registrar.

Registration Authority (RA): Any Legal Entity that is responsible for identification and authentication of subjects of Certificates, but is not a CA, and hence does not sign or issue Certificates. An RA may assist in the certificate application process or revocation process or both. When “RA” is used as an adjective to describe a role or function, it does not necessarily imply a separate body, but can be part of the CA.

Reliable Data Source: An identification document or source of data used to verify Subject Identity Information that is generally recognized among commercial enterprises and governments as reliable, and which was created by a third party for a purpose other than the Applicant obtaining a Certificate.

Reliable Method of Communication: A method of communication, such as a postal/courier delivery address, telephone number, or email address, that was verified using a source other than the Applicant Representative.

Relying Party: Any natural person or Legal Entity that relies on a Valid Certificate. An Application Software Supplier is not considered a Relying Party when software distributed by such Supplier merely displays information relating to a Certificate.

Repository: An online database containing publicly disclosed PKI governance documents (such as Certificate Policies and Certification Practice Statements) and Certificate status information, either in the form of a CRL or an OCSP response.

Request Token: A value derived in a method specified by the CA which binds this demonstration of control to the certificate request.

Required Website Content: Either a Random Value or a Request Token, together with additional information that uniquely identifies the Subscriber, as specified by the CA.

Reserved IP Address: An IPv4 or IPv6 address that the IANA has marked as reserved:

Root CA: The top level Certification Authority whose Root Certificate is distributed by Application Software Suppliers and that issues Subordinate CA Certificates.

Root Certificate: The self-signed Certificate issued by the Root CA to identify itself and to facilitate verification of Certificates issued to its Subordinate CAs.

Secure Multipurpose Internet Mail Extensions (S/MIME): S/MIME is a standard for public key encryption and signing of MIME data.

Secure Sockets Layer (SSL): SSL is a cryptographic protocol that was used to protect Internet Communications since 1995, until it was deprecated by the Internet Engineering Task Force, and was succeeded by TLS. It was so influential though, that people still colloquially use the term SSL to refer to TLS.

Sovereign State: A state or country that administers its own government, and is not dependent upon, or subject to, another power.

Subject: The natural person, device, system, unit, or Legal Entity identified in a Certificate as the Subject. The Subject is either the Subscriber or a device under the control and operation of the Subscriber.

Subject Identity Information: Information that identifies the Certificate Subject. Subject Identity Information does not include a domain name listed in the subjectAltName extension or the Subject commonName field.

Subordinate CA: A Certification Authority whose Certificate is signed by the Root CA, or another Subordinate CA.

Subscriber: A natural person or Legal Entity to whom a Certificate is issued and who is legally bound by a Subscriber Agreement or Terms of Use.

Subscriber Agreement: An agreement between the CA and the Applicant/Subscriber that specifies the rights and responsibilities of the parties.

subsidiary_company: A company that is controlled by a Parent Company.

Technically Constrained Subordinate CA Certificate: A Subordinate CA certificate which uses a combination of Extended Key Usage settings and Name Constraint settings to limit the scope within which the Subordinate CA Certificate may issue Subscriber or additional Subordinate CA Certificates.

Terms of Use: Provisions regarding the safekeeping and acceptable uses of a Certificate issued in accordance with these Requirements when the Applicant/Subscriber is an Affiliate of the CA or is the CA.

Test Certificate: A Certificate with a maximum validity period of 30 days and which: (i) includes a critical extension with the specified Test Certificate CABF OID (, or (ii) is issued under a CA where there are no certificate paths/chains to a root certificate subject to these Requirements.

Top-Level Domain (TLD): A top-level domain is located at the highest level in the hierarchical Domain Name System of the Internet. For all domains in lower levels, it is the last part of the domain name, that is, the last label of a fully qualified domain name. For example, in the domain name www.example.com, the top-level domain is com.

Transport Layer Security (TLS): TLS is a cryptographic protocol maintained by IETF, that provides communications security over a computer network. TLS is the de-facto security protocol that browsers use to securely communicate with HTTPS web servers. TLS guarantees the integrity and privacy of all exchanged information.

Trustworthy System: Computer hardware, software, and procedures that are: reasonably secure from intrusion and misuse; provide a reasonable level of availability, reliability, and correct operation; are reasonably suited to performing their intended functions; and enforce the applicable security policy.

Unregistered Domain Name: A Domain Name that is not a Registered Domain Name.

Valid Certificate: A Certificate that passes the validation procedure specified in RFC 5280.

Validation Specialists: Someone who performs the information verification duties specified by these Requirements.

Validity Period: The period of time measured from the date when the Certificate is issued until the Expiry Date.

Voice Over Internet Protocol (VOIP): Voice over IP is a technology allowing the delivery of voice and media communications over Internet Protocol (IP) networks, such as the Internet. The terms Internet or broadband telephony, specifically refer to the provisioning of communications services (voice, fax, SMS, voice-messaging) over the public Internet, rather than via the public switched telephone network (PSTN).

WHOIS: Information retrieved directly from the Domain Name Registrar or registry operator via the protocol defined in RFC 3912, the Registry Data Access Protocol defined in RFC 7482, or an HTTPS website.

Wildcard Certificate: A Certificate containing an asterisk (*) in the left-most position of any of the Subject Fully Qualified Domain Names contained in the Certificate.

Wildcard Domain Name: A Domain Name consisting of a single asterisk character followed by a single full stop character (“*.”) followed by a Fully Qualified Domain Name.

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