1.1 Glossary

This document uses the following terms:

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.

advanced certification authority (CA): A certification authority (CA) (server role of the Windows Client Certificate Enrollment Protocol) that supports subprotocols 1–6, as specified in [MS-WCCE] section 1.3.1.

AIK public key (AIKPub): The public key portion of an Attestation Identity Key's private/public key pair.

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.

attestation certificate (AIKCert): An X.509 certificate, issued by a Privacy-CA ([TCG-Cred] section 2.6), that contains the public portion of an Attestation Identity Key signed by a Privacy-CA. It states that the public key is associated with a valid TPM. See [TCG-Cred] section 3.4 for more information.

Attestation Identity Key (AIK): An asymmetric (public/private) key pair that can substitute for the Endorsement Key (EK) as an identity for the trusted platform module (TPM). The private portion of an AIK can never be revealed or used outside the TPM and can only be used inside the TPM for a limited set of operations. Furthermore, it can only be used for signing, and only for limited, TPM-defined operations.

attribute: A characteristic of some object or entity, typically encoded as a name/value pair.

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

backward cross certificate: Given a set of signing certificates for a specific certificate authority (CA), this certificate is a cross certificate created between one of the certificates in the CA's set and a certificate that precedes the set certificate (based on the value of the notBefore field), and has a different public-private key pair than the certificate with the set's.

big-endian: Multiple-byte values that are byte-ordered with the most significant byte stored in the memory location with the lowest address.

binary large object (BLOB): A collection of binary data stored as a single entity in a database.

CA exit algorithm: An optional addition to the CA (WCCE server role) functionality. The algorithm is invoked whenever a certificate is issued. The algorithm can perform customer-defined, post-processing functionality such as publishing the certificate to a predefined path or sending an email message about the issued certificate to an administrator.

CA policy algorithm: An algorithm that determines whether to issue a certificate for a specified certificate request and defines how that certificate is constructed.

CA role separation: The configuration of a CA to disallow an administrator CA operator from performing multiple roles on a CA simultaneously. Role separation is the concept of configuring a CA to enhance security by allowing a user to be assigned only a single role, such as auditor, backup manager, administrator, or certificate manager, at one time. Role separation is an optional Common Criteria requirement, as specified in [CIMC-PP].

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 issuance: The granting of a digital certificate to an end entity by a certificate authority (CA) as part of the certification process. Sometimes referred to as simply "issuance".

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 revocation list (CRL): A list of certificates that have been revoked by the certification authority (CA) that issued them (that have not yet expired of their own accord). The list has to be cryptographically signed by the CA that issues it. Typically, the certificates are identified by serial number. In addition to the serial number for the revoked certificates, the CRL contains the revocation reason for each certificate and the time the certificate was revoked. As described in [RFC3280], two types of CRLs commonly exist in the industry. Base CRLs keep a complete list of revoked certificates, while delta CRLs maintain only those certificates that have been revoked since the last issuance of a base CRL. For more information, see [X509] section 7.3, [MSFT-CRL], and [RFC3280] section 5.

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: The certificate request and issuance process whereby an end entity first makes itself known to a certification authority (CA) (directly, or through a registration authority) through the submission of a certificate enrollment request, prior to that CA issuing a certificate or certificates for that end entity.

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 is to 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 has to 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.

container: An object in the directory that can serve as the parent for other objects. In the absence of schema constraints, all objects would be containers. The schema allows only objects of specific classes to be containers.

cross certificate: An [X509] digital certificate issued between two existing independent certification authorities (CAs) for the purpose of extending or constraining public key infrastructure (PKI) trust hierarchies. A cross certificate is specified in [X509] section 3.3.21. For an introduction to cross certificates and cross certification, see [MSFT-CROSSCERT].

cross-certification: The certificate issuance process by which two certificate authorities (CAs), CA1 and CA2, issue specialized certificates so that any relying party (RP) that has CA1 in its trust root but not CA2 can link from CA1 to CA2 and thereby validate certificates in the hierarchy under CA2 and make use of those. For more information on cross-certification, see section 3.5 of [RFC3280]. For an introduction to cross-certificates and cross-certification, see [MSFT-CROSSCERT].

Cryptographic Message Syntax (CMS): A public standard that defines how to digitally sign, digest, authenticate, or encrypt arbitrary message content, as specified in [RFC3852].

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

digital certificate: See the "digital certificate definition standard," as described in [X509].

digital signature: A message authenticator that is typically derived from a cryptographic operation using an asymmetric algorithm and private key. When a symmetric algorithm is used for this purpose, the authenticator is typically called a Message Authentication Code (MAC). In some contexts, the term digital signature is used to refer to either type of authenticator; however, in this Windows Client Certificate Enrollment Protocol, the term digital signature is used only for authenticators created by asymmetric algorithms.  For more information, see [SCHNEIER] chapters 2 and 20.

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.

directory object: An Active Directory object, which is a specialization of the "object" concept that is described in [MS-ADTS] section 1 or [MS-DRSR] section 1, Introduction, under Pervasive Concepts. An Active Directory object can be identified by the objectGUID attribute of a dsname according to the matching rules defined in [MS-DRSR] section 5.50, DSNAME. The parent-identifying attribute (not exposed as an LDAP attribute) is parent. Active Directory objects are similar to LDAP entries, as defined in [RFC2251]; the differences are specified in [MS-ADTS] section 3.1.1.3.1.

directory service (DS): A service that stores and organizes information about a computer network's users and network shares, and that allows network administrators to manage users' access to the shares. See also Active Directory.

Distinguished Encoding Rules (DER): A method for encoding a data object based on Basic Encoding Rules (BER) encoding but with additional constraints. DER is used to encode X.509 certificates that need to be digitally signed or to have their signatures verified.

distinguished name (DN): A name that uniquely identifies an object by using the relative distinguished name (RDN) for the object, and the names of container objects and domains that contain the object. The distinguished name (DN) identifies the object and its location in a tree.

Distributed Component Object Model (DCOM): The Microsoft Component Object Model (COM) specification that defines how components communicate over networks, as specified in [MS-DCOM].

domain: A set of users and computers sharing a common namespace and management infrastructure. At least one computer member of the set has to 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 1.1.1.5 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 1.1.1.5.2 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].

Domain Name System (DNS): A hierarchical, distributed database that contains mappings of domain names to various types of data, such as IP addresses. DNS enables the location of computers and services by user-friendly names, and it also enables the discovery of other information stored in the database.

EK private key (EKPriv): The private key portion of an endorsement key's private/public key pair.

EK public key (EKPub): The public key portion of an endorsement key's private/public key pair.

encryption: In cryptography, the process of obscuring information to make it unreadable without special knowledge.

end entity: The keyholder (person or computer) to whose key or name a particular certificate refers.

endorsement certificate (EKCert): An X.509 certificate issued by a platform manufacturer indicating that the trusted platform module (TPM) with the specified endorsement key was built into a specified computer platform. See [TCG-Cred] section 3.2 for more information.

endorsement key (EK): A Rivest-Shamir-Adleman (RSA) public and private key pair, which is created randomly on the trusted platform module (TPM) at manufacture time and cannot be changed. The private key never leaves the TPM, while the public key is used for attestation and for encryption of sensitive data sent to the TPM. See [TCG-Cred] section 2.4 for more information.

enhanced key usage (EKU): An extension that is a collection of object identifiers (OIDs) that indicate the applications that use the key.

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 agent (EA): An entity that can request a certificate on behalf of other entities. For more information, see Request On Behalf Of (ROBO).

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.

exchange certificate: A certificate that can be used for encryption purposes. This certificate can be used by clients to encrypt their private keys as part of their certificate request. In Windows environments, an enterprise certificate authority (CA) creates an exchange certificate periodically (by default, weekly), and returns the exchange certificate upon request of a client. For more information, see [MSFT-ARCHIVE].

forward cross certificate: Given a set of signing certificates for a specific certificate authority (CA), this certificate is a cross certificate created between one of the certificates in the CA's set and a certificate that follows the set certificate (based on the value of the notBefore field), and has a different public-private key pair than the certificate with the set's.

fully qualified domain name (FQDN): An unambiguous domain name that gives an absolute location in the Domain Name System's (DNS) hierarchy tree, as defined in [RFC1035] section 3.1 and [RFC2181] section 11.

globally unique identifier (GUID): A term used interchangeably with universally unique identifier (UUID) in Microsoft protocol technical documents (TDs). Interchanging the usage of these terms does not imply or require a specific algorithm or mechanism to generate the value. Specifically, the use of this term does not imply or require that the algorithms described in [RFC4122] or [C706] have to be used for generating the GUID. See also universally unique identifier (UUID).

Interface Definition Language (IDL): The International Standards Organization (ISO) standard language for specifying the interface for remote procedure calls. For more information, see [C706] section 4.

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 archival certificate: See key recovery certificate.

key attestation: See attestation.

key exchange: A synonym for key establishment. The procedure that results in shared secret keying material among different parties. Key agreement and key transport are two forms of key exchange. For more information, see [CRYPTO] section 1.11, [SP800-56A] section 3.1, and [IEEE1363] section 3.

key length: A value specified by a cryptographic module that indicates the length of the public-private key pair and symmetric keys that are used within the module. The key length values are expressed in bits. For more information about cryptographic key lengths, see [SP800-56A] section 3.1.

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].

key recovery certificate: A certificate with the unique object identifier (OID) in the extended key usage extension for key archival. Also known as key archival certificate.

key spec: Specifies how a given private key is used within a cryptographic module.

KEYGEN: An HTML tag defined by Netscape to allow HTML communications with a browser to trigger certificate enrollment. For more information on usage, see [HTMLQ-keygen] and section 1.3.2.4.

keyholder: The entity that holds a private key and is therefore capable of signing and decrypting. The keyholder of a public key is defined as the keyholder of the corresponding private key.

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].

little-endian: Multiple-byte values that are byte-ordered with the least significant byte stored in the memory location with the lowest address.

object: (1) 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.

(2) In the DCOM protocol, a software entity that implements one or more object remote protocol (ORPC) interfaces and which is uniquely identified, within the scope of an object exporter, by an object identifier (OID). For more information, see [MS-DCOM].

object identifier (OID): In the Lightweight Directory Access Protocol (LDAP), a sequence of numbers in a format described by [RFC1778]. In many LDAP directory implementations, an OID is the standard internal representation of an attribute. In the directory model used in this specification, the more familiar ldapDisplayName represents an attribute.

object remote procedure call (ORPC): A remote procedure call whose target is an interface on an object. The target interface (and therefore the object) is identified by an interface pointer identifier (IPID).

opnum: An operation number or numeric identifier that is used to identify a specific remote procedure call (RPC) method or a method in an interface. For more information, see [C706] section 12.5.2.12 or [MS-RPCE].

principal: A unique entity identifiable by a security identifier (SID) that is typically the requester of access to securable objects or resources. It often corresponds to a human user but can also be a computer or service. It is sometimes referred to as a security principal.

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.

pseudo-random number generator (PRNG): An algorithm that generates values (numbers, bits, and so on) that give the appearance of being random from the point of view of any known test. If initialized with a true random value (called its "seed"), the output of a cryptographically strong PRNG will have the same resistance to guessing as a true random source.

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.

public key algorithm: An asymmetric cipher that uses two cryptographic keys: one for encryption, the public key, and the other for decryption, the private key. In signature and verification, the roles are reversed: public key is used for verification, and private key is used for signature generation. Examples of public key algorithms are described in various standards, including Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA) in FIPS 186-2 ([FIPS186]), RSA in PKCS#1 ([RFC8017]), the National Institute of Standards and Technology (NIST) also published an introduction to public key technology in SP800-32 ([SP800-32] section 5.6).

public key infrastructure (PKI): The laws, policies, standards, and software that regulate or manipulate certificates and public and private keys. In practice, it is a system of digital certificates, certificate authorities (CAs), and other registration authorities that verify and authenticate the validity of each party involved in an electronic transaction. For more information, see [X509] section 6.

public-private key pair: The association of a public key and its corresponding private key when used in cryptography. Also referred to simply as a "key pair". For an introduction to public-private key pairs, see [IEEE1363] section 3.

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.

relative distinguished name (RDN): In the Active Directory directory service, the unique name of a child element relative to its parent in Active Directory. The RDN of a child element combined with the fully qualified domain name (FQDN) of the parent forms the FQDN of the child.

relying party (RP): The entity (person or computer) using information from a certificate in order to make a security decision. Typically, the RP is responsible for guarding some resource and applying access control policies based on information learned from a certificate.

Request On Behalf Of (ROBO): A request process that is used during a proxy enrollment process in which one user, typically an administrator, enrolls for a certificate for a second user by using the administrator credentials.

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

Rivest-Shamir-Adleman (RSA): A system for public key cryptography. RSA is specified in [RFC8017].

root CA: A type of certificate authority (CA) that is directly trusted by an end entity, including a relying party; that is, securely acquiring the value of a root CA public key requires some out-of-band steps. This term is not meant to imply that a root CA is necessarily at the top of any hierarchy, simply that the CA in question is trusted directly (as specified in [RFC2510]). A root CA is implemented in software and in Windows, is the topmost CA in a CA hierarchy, and is the trust point for all certificates that are issued by the CAs in the CA hierarchy. If a user, computer, or service trusts a root CA, it implicitly trusts all certificates that are issued by all other CAs in the CA hierarchy. For more information, see [RFC3280].

root certificate: A self-signed certificate that identifies the public key of a root certification authority (CA) and has been trusted to terminate a certificate chain.

sanitized name: The form of a certification authority (CA) name that is used in file names (such as for a certificate revocation list (CRL); see [MSFT-CRL] for more information) and in other contexts where character sets are restricted. The process of sanitizing the CA name is necessary to remove characters that are illegal for file names, registry key names, or distinguished name (DN) values, or that are illegal for technology-specific reasons.

SHA-1 hash: A hashing algorithm as specified in [FIPS180-2] that was developed by the National Institute of Standards and Technology (NIST) and the National Security Agency (NSA).

signing certificates: The certificate that represents the identity of an entity (for example, a certification authority (CA), a web server or an S/MIME mail author) and is used to verify signatures made by the private key of that entity. For more information, see [RFC3280].

standalone CA: A certification authority (CA) that is not a member of a domain. For more information, see [MSFT-PKI].

standard CA: A CA (server role of the Windows Client Certificate Enrollment Protocol) that supports subprotocols 1–5, as specified in section 1.3.1.

subordinate CA: A type of CA that is not a root CA for a relying party (RP) or for a client. A subordinate CA is a CA whose certificate is signed by some other CA, as specified in [RFC2510].

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.

Triple Data Encryption Standard: A block cipher that is formed from the Data Encryption Standard (DES) cipher by using it three times.

trust: To accept another authority's statements for the purposes of authentication and authorization, especially in the case of a relationship between two domains. If domain A trusts domain B, domain A accepts domain B's authentication and authorization statements for principals represented by security principal objects in domain B; for example, the list of groups to which a particular user belongs. As a noun, a trust is the relationship between two domains described in the previous sentence.

trust root: A collection of root CA keys trusted by the RP. A store within the computer of a relying party that is protected from tampering and in which the root keys of all root CAs are held. Those root keys are typically encoded within self-signed certificates, and the contents of a trust root are therefore sometimes called root certificates.

trusted platform module (TPM): A component of a trusted computing platform. The TPM stores keys, passwords, and digital certificates. See [TCG-Architect] for more information.

Universal Naming Convention (UNC): A string format that specifies the location of a resource. For more information, see [MS-DTYP] section 2.2.57.

user principal name (UPN): A user account name (sometimes referred to as the user logon name) and a domain name that identifies the domain in which the user account is located. This is the standard usage for logging on to a Windows domain. The format is: someone@example.com (in the form of an email address). In Active Directory, the userPrincipalName attribute of the account object, as described in [MS-ADTS].

UTF-16: A standard for encoding Unicode characters, defined in the Unicode standard, in which the most commonly used characters are defined as double-byte characters. Unless specified otherwise, this term refers to the UTF-16 encoding form specified in [UNICODE5.0.0/2007] section 3.9.

UTF-8: A byte-oriented standard for encoding Unicode characters, defined in the Unicode standard. Unless specified otherwise, this term refers to the UTF-8 encoding form specified in [UNICODE5.0.0/2007] section 3.9.

Windows registry: The Windows implementation of the registry.

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.