1.1 Glossary

This document uses the following terms:

access control entry (ACE): An entry in an access control list (ACL) that contains a set of user rights and a security identifier (SID) that identifies a principal for whom the rights are allowed, denied, or audited.

access control list (ACL): A list of access control entries (ACEs) that collectively describe the security rules for authorizing access to some resource; for example, an object or set of objects.

Active Directory: The Windows implementation of a general-purpose directory service, which uses LDAP as its primary access protocol. Active Directory stores information about a variety of objects in the network such as user accounts, computer accounts, groups, and all related credential information used by Kerberos [MS-KILE]. Active Directory is either deployed as Active Directory Domain Services (AD DS) or Active Directory Lightweight Directory Services (AD LDS), which are both described in [MS-ADOD]: Active Directory Protocols Overview.

asymmetric algorithm: A synonym for public key algorithm. For an introduction to these concepts and related terminology, see [RSAFAQ].

attestation: A process of establishing some property of a computer platform or of a trusted platform module (TPM) key, in part through TPM cryptographic operations.

attribute: An identifier for a single or multivalued data element that is associated with a directory object. An object consists of its attributes and their values. For example, cn (common name), street (street address), and mail (email addresses) can all be attributes of a user object. An attribute's schema, including the syntax of its values, is defined in an attributeSchema object.

autoenrollment: An automated process that performs certificate enrollment and renewal. For more information about autoenrollment behavior, see [MS-CERSOD].

certificate: A certificate is a collection of attributes and extensions that can be stored persistently. The set of attributes in a certificate can vary depending on the intended usage of the certificate. A certificate securely binds a public key to the entity that holds the corresponding private key. A certificate is commonly used for authentication and secure exchange of information on open networks, such as the Internet, extranets, and intranets. Certificates are digitally signed by the issuing certification authority (CA) and can be issued for a user, a computer, or a service. The most widely accepted format for certificates is defined by the ITU-T X.509 version 3 international standards. For more information about attributes and extensions, see [RFC3280] and [X509] sections 7 and 8.

certificate enrollment: The process of acquiring a digital certificate from a certificate authority (CA), which typically requires an end entity to first makes itself known to the CA (either directly, or through a registration authority). This certificate and its associated private key establish a trusted identity for an entity that is using the public key–based services and applications. Also referred to as simply "enrollment".

certificate renewal request: An enrollment request for a new certificate where the request is signed using an existing certificate. The renewal request can use the key pair from the existing certificate or a new key pair. After the new certificate has been issued, it is meant (but not required) to replace the older certificate (a renewed certificate).

certificate template: A list of attributes that define a blueprint for creating an X.509 certificate. It is often referred to in non-Microsoft documentation as a "certificate profile". A certificate template is used to define the content and purpose of a digital certificate, including issuance requirements (certificate policies), implemented X.509 extensions such as application policies, key usage, or extended key usage as specified in [X509], and enrollment permissions. Enrollment permissions define the rules by which a certification authority (CA) will issue or deny certificate requests. In Windows environments, certificate templates are stored as objects in the Active Directory and used by Microsoft enterprise CAs.

certification authority (CA): A third party that issues public key certificates. Certificates serve to bind public keys to a user identity. Each user and certification authority (CA) can decide whether to trust another user or CA for a specific purpose, and whether this trust should be transitive. For more information, see [RFC3280].

common name (CN): A string attribute of a certificate that is one component of a distinguished name (DN). In Microsoft Enterprise uses, a CN must be unique within the forest where it is defined and any forests that share trust with the defining forest. The website or email address of the certificate owner is often used as a common name. Client applications often refer to a certification authority (CA) by the CN of its signing certificate.

cryptographic service provider (CSP): A software module that implements cryptographic functions for calling applications that generates digital signatures. Multiple CSPs may be installed. A CSP is identified by a name represented by a NULL-terminated Unicode string.

digital signature: A message authenticator that is typically derived from a cryptographic operation by using an asymmetric algorithm and private key. When a symmetric algorithm is used for this purpose, the authenticator is typically referred to as a Message Authentication Code (MAC).

directory: The database that stores information about objects such as users, groups, computers, printers, and the directory service that makes this information available to users and applications.

discretionary access control list (DACL): An access control list (ACL) that is controlled by the owner of an object and that specifies the access particular users or groups can have to the object.

distinguished name (DN): In Lightweight Directory Access Protocol (LDAP), an LDAP Distinguished Name, as described in [RFC2251] section 4.1.3. The DN of an object is the DN of its parent, preceded by the RDN of the object. For example: CN=David Thompson, OU=Users, DC=Microsoft, DC=COM. For definitions of CN and OU, see [RFC2256] sections 5.4 and 5.12, respectively.

domain: A set of users and computers sharing a common namespace and management infrastructure. At least one computer member of the set must act as a domain controller (DC) and host a member list that identifies all members of the domain, as well as optionally hosting the Active Directory service. The domain controller provides authentication of members, creating a unit of trust for its members. Each domain has an identifier that is shared among its members. For more information, see [MS-AUTHSOD] section and [MS-ADTS].

domain controller (DC): The service, running on a server, that implements Active Directory, or the server hosting this service. The service hosts the data store for objects and interoperates with other DCs to ensure that a local change to an object replicates correctly across all DCs. When Active Directory is operating as Active Directory Domain Services (AD DS), the DC contains full NC replicas of the configuration naming context (config NC), schema naming context (schema NC), and one of the domain NCs in its forest. If the AD DS DC is a global catalog server (GC server), it contains partial NC replicas of the remaining domain NCs in its forest. For more information, see [MS-AUTHSOD] section and [MS-ADTS]. When Active Directory is operating as Active Directory Lightweight Directory Services (AD LDS), several AD LDS DCs can run on one server. When Active Directory is operating as AD DS, only one AD DS DC can run on one server. However, several AD LDS DCs can coexist with one AD DS DC on one server. The AD LDS DC contains full NC replicas of the config NC and the schema NC in its forest. The domain controller is the server side of Authentication Protocol Domain Support [MS-APDS].

enroll: To request and acquire a digital certificate from a certificate authority (CA). This is typically accomplished through a certificate enrollment process.

Enroll On Behalf Of (EOBO): A proxy enrollment process in which one user, typically an administrator, enrolls for a certificate for a second user by using the administrator credentials.

enrollment permissions: A list of administrator-defined rights or access control lists (ACLs) that define the capability of a given client (user, machine, or device). Enrollment permissions can define a client capability to read a certificate template, write a certificate template, enroll for a certificate based on a specified certificate template, auto-enroll for a certificate based on a specified certificate template, or change permissions on a certificate template. Enrollment permissions are stored on a certificate template and are enforced by the certificate authority (CA). For more information, see [MSFT-TEMPLATES].

enterprise certificate authority (enterprise CA): A certificate authority (CA) that is a member of a domain and that uses the domain's Active Directory service to store policy, authentication, and other information related to the operation of the CA. Specifically, the enterprise CA is a server implementation of the Windows Client Certificate Enrollment Protocol that uses the certificate template data structure (see [MS-CRTD]) in its CA policy algorithm implementation.

fully qualified domain name (FQDN): In Active Directory, a fully qualified domain name (FQDN) that identifies a domain.

key: In cryptography, a generic term used to refer to cryptographic data that is used to initialize a cryptographic algorithm. Keys are also sometimes referred to as keying material.

key archival: The process by which the entity requesting the certificate also submits the private key during the process. The private key is encrypted such that only a key recovery agent can obtain it, preventing accidental disclosure, but preserving a copy in case the entity is unable or unwilling to decrypt data.

key recovery agent (KRA): A user, machine, or registration authority that has enrolled and obtained a key recovery certificate. A KRA is any entity that possesses a KRA private key and certificate. For more information on KRAs and the archival process, see [MSFT-ARCHIVE].

Lightweight Directory Access Protocol (LDAP): The primary access protocol for Active Directory. Lightweight Directory Access Protocol (LDAP) is an industry-standard protocol, established by the Internet Engineering Task Force (IETF), which allows users to query and update information in a directory service (DS), as described in [MS-ADTS]. The Lightweight Directory Access Protocol can be either version 2 [RFC1777] or version 3 [RFC3377].

NetBIOS name: A 16-byte address that is used to identify a NetBIOS resource on the network. For more information, see [RFC1001] and [RFC1002].

object: In Active Directory, an entity consisting of a set of attributes, each attribute with a set of associated values. For more information, see [MS-ADTS]. See also directory object.

object identifier (OID): In the context of a directory service, a number identifying an object class or attribute. Object identifiers are issued by the ITU and form a hierarchy. An OID is represented as a dotted decimal string (for example, ""). For more information on OIDs, see [X660] and [RFC3280] Appendix A. OIDs are used to uniquely identify certificate templates available to the certification authority (CA). Within a certificate, OIDs are used to identify standard extensions, as described in [RFC3280] section 4.2.1.x, as well as non-standard extensions.

private key: One of a pair of keys used in public-key cryptography. The private key is kept secret and is used to decrypt data that has been encrypted with the corresponding public key. For an introduction to this concept, see [CRYPTO] section 1.8 and [IEEE1363] section 3.1.

public key: One of a pair of keys used in public-key cryptography. The public key is distributed freely and published as part of a digital certificate. For an introduction to this concept, see [CRYPTO] section 1.8 and [IEEE1363] section 3.1.

registration authority (RA): The authority in a PKI that verifies user requests for a digital certificate and indicates to the certificate authority (CA) that it is acceptable to issue a certificate.

revocation: The process of invalidating a certificate. For more details, see [RFC3280] section 3.3.

Secure/Multipurpose Internet Mail Extensions (S/MIME): A standard for encrypted and digitally signed electronic mail that allows users to send encrypted messages and authenticate received messages.

security descriptor: A data structure containing the security information associated with a securable object. A security descriptor identifies an object's owner by its security identifier (SID). If access control is configured for the object, its security descriptor contains a discretionary access control list (DACL) with SIDs for the security principals who are allowed or denied access. Applications use this structure to set and query an object's security status. The security descriptor is used to guard access to an object as well as to control which type of auditing takes place when the object is accessed. The security descriptor format is specified in [MS-DTYP] section 2.4.6; a string representation of security descriptors, called SDDL, is specified in [MS-DTYP] section 2.5.1.

security identifier (SID): An identifier for security principals that is used to identify an account or a group. Conceptually, the SID is composed of an account authority portion (typically a domain) and a smaller integer representing an identity relative to the account authority, termed the relative identifier (RID). The SID format is specified in [MS-DTYP] section 2.4.2; a string representation of SIDs is specified in [MS-DTYP] section 2.4.2 and [MS-AZOD] section

symmetric algorithm: A cryptographic algorithm that uses one secret key that can be shared between authorized parties. The key must be kept secret between communicating parties. The same key is used for both encryption and decryption. For an introduction to this concept and terminology, see [CRYPTO] section 1.5, [IEEE1363] section 3, and [SP800-56A] section 3.1.

symmetric key: A secret key used with a cryptographic symmetric algorithm. The key needs to be known to all communicating parties. For an introduction to this concept, see [CRYPTO] section 1.5.

MAY, SHOULD, MUST, SHOULD NOT, MUST NOT: These terms (in all caps) are used as defined in [RFC2119]. All statements of optional behavior use either MAY, SHOULD, or SHOULD NOT.