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access control
The process of controlling what particular users are allowed to do. For example, access control to servers is typically based on an identity, established by a password or a certificate, and on rules regarding what that entity can do.
The person who installs and configures one or more Certificate System managers and sets up privileged users, or agents, for them.
Confident identification; assurance that a party to some computerized transaction is not an impostor. Authentication typically involves the use of a password, certificate, PIN, or other information to validate identity over a computer network.

See Also password-based authentication, certificate-based authentication, client authentication, server authentication.

authentication module
A set of rules (implemented as a Java™ class) for authenticating an end entity, agent, administrator, or any other entity that needs to interact with a Certificate System subsystem. In the case of typical end-user enrollment, after the user has supplied the information requested by the enrollment form, the enrollment servlet uses an authentication module associated with that form to validate the information and authenticate the user's identity.

See Also servlet.

authentication server
A server that issues tickets for a desired service which are in turn given to users for access to the service. The AS responds to requests from clients who do not have or do not send credentials with a request. It is usually used to gain access to the ticket-granting server (TGS) service by issuing a ticket-granting ticket (TGT). The AS usually runs on the same host as the key distribution center (KDC).
Permission to access a resource controlled by a server. Authorization typically takes place after the ACLs associated with a resource have been evaluated by a server.
automated enrollment
A way of configuring a Certificate System subsystem that allows automatic authentication for end-entity enrollment, without human intervention. With this form of authentication, a certificate request that completes authentication module processing successfully is automatically approved for profile processing and certificate issuance.


bind DN
A user ID, in the form of a distinguished name (DN), used with a password to authenticate to Red Hat Directory Server.


CA certificate
A certificate that identifies a certificate authority.

See Also certificate authority (CA), root CA.

CA server key
The SSL server key of the server providing a CA service.
CA signing key
The private key that corresponds to the public key in the CA certificate. A CA uses its signing key to sign certificates and CRLs.
Digital data, formatted according to the X.509 standard, that specifies the name of an individual, company, or other entity (the subject name of the certificate) and certifies that a public key, which is also included in the certificate, belongs to that entity. A certificate is issued and digitally signed by a certificate authority (CA). A certificate's validity can be verified by checking the CA's digital signature through public-key cryptography techniques. To be trusted within a public-key infrastructure (PKI), a certificate must be issued and signed by a CA that is trusted by other entities enrolled in the PKI.
certificate authority (CA)
A trusted entity that issues a certificate after verifying the identity of the person or entity the certificate is intended to identify. A CA also renews and revokes certificates and generates CRLs. The entity named in the issuer field of a certificate is always a CA. Certificate authorities can be independent third parties or a person or organization using certificate-issuing server software, such as Red Hat Certificate System.
certificate chain
A hierarchical series of certificates signed by successive certificate authorities. A CA certificate identifies a certificate authority (CA) and is used to sign certificates issued by that authority. A CA certificate can in turn be signed by the CA certificate of a parent CA, and so on up to a root CA. Certificate System allows any end entity to retrieve all the certificates in a certificate chain.
Certificate Manager
An independent Certificate System subsystem that acts as a certificate authority. A Certificate Manager instance issues, renews, and revokes certificates, which it can publish along with CRLs to an LDAP directory. It accepts requests from end entities.

See Also certificate authority (CA).

certificate profile
A set of configuration settings that defines a certain type of enrollment. The certificate profile sets policies for a particular type of enrollment along with an authentication method in a certificate profile.
certificate revocation list (CRL)
As defined by the X.509 standard, a list of revoked certificates by serial number, generated and signed by a certificate authority (CA).
Certificate System subsystem
One of the five Certificate System managers: Certificate Manager, Online Certificate Status Manager, Data Recovery Manager, Token Key Service, or Token Processing System.
certificate-based authentication
Authentication based on certificates and public-key cryptography.

See Also password-based authentication.


See cryptographic algorithm.

Encrypted data.
An entity on the network (a user, a host, or an application) that can receive a ticket from Kerberos.
client authentication
The process of identifying a client to a server, such as with a name and password or with a certificate and some digitally signed data.

See Also certificate-based authentication, password-based authentication, server authentication.

client SSL certificate
A certificate used to identify a client to a server using the SSL protocol.

See Also Secure Sockets Layer (SSL).

credential cache
A file which contains the keys for encrypting communications between a user and various network services. Kerberos 5 supports a framework for using other cache types, such as shared memory, but files are more thoroughly supported.
Also called a ticket file.
A temporary set of electronic credentials that verify the identity of a client for a particular service. Also called a ticket.

See certificate revocation list (CRL).

crypt hash
A one-way hash used to authenticate users. These are more secure than using unencrypted data, but they are still relatively easy to decrypt for an experienced cracker.
cryptographic algorithm
A set of rules or directions used to perform cryptographic operations such as encryption and decryption.
cryptographic module

See PKCS #11 module.


Data Encryption Standard (DES)
A FIPS-approved cryptographic algorithm required by FIPS 140-1 and specified by FIPS PUBS 46-2. DES, which uses 56-bit keys, is a standard encryption and decryption algorithm that has been used successfully throughout the world for more than 20 years. For detailed information, see

See Also FIPS PUBS 140-1.

Data Recovery Manager
An optional, independent Certificate System subsystem that manages the long-term archival and recovery of RSA encryption keys for end entities. A Certificate Manager can be configured to archive end entities' encryption keys with a Data Recovery Manager before issuing new certificates. The Data Recovery Manager is useful only if end entities are encrypting data, such as sensitive email, that the organization may need to recover someday. It can be used only with end entities that support dual key pairs: two separate key pairs, one for encryption and one for digital signatures.
Unscrambling data that has been encrypted.

See Also encryption.

delta CRL
A CRL containing a list of those certificates that have been revoked since the last full CRL was issued.
digital signature
To create a digital signature, the signing software first creates a one-way hash from the data to be signed, such as a newly issued certificate. The one-way hash is then encrypted with the private key of the signer. The resulting digital signature is unique for each piece of data signed. Even a single comma added to a message changes the digital signature for that message. Successful decryption of the digital signature with the signer's public key and comparison with another hash of the same data provides tamper detection. Verification of the certificate chain for the certificate containing the public key provides authentication of the signer.

See Also nonrepudiation, encryption.

distinguished name (DN)
A series of attribute-value assertions that, together, identify the subject of a certificate. This usually follows a hierarchy, moving from the name of the entity through its physical location and location in the organization.
dual key pair
Two public-private key pairs, four keys altogether, corresponding to two separate certificates. The private key of one pair is used for signing operations, and the public and private keys of the other pair are used for encryption and decryption operations. Each pair corresponds to a separate certificate.

See Also encryption key, public-key cryptography, signing key.


Scrambling information in a way that disguises its meaning.

See Also decryption.

encryption key
A private key used for encryption only. An encryption key and its equivalent public key, plus a signing key and its equivalent public key, constitute a dual key pair.
The process of requesting and receiving an X.509 certificate for use in a public-key infrastructure (PKI). Also known as registration.


Federal Information Standards Publications (FIPS PUBS) 140-1 is a US government standard for implementations of cryptographic modules, hardware or software that encrypts and decrypts data or performs other cryptographic operations, such as creating or verifying digital signatures. Many products sold to the US government must comply with one or more of the FIPS standards. See
A system or combination of systems that enforces a boundary between two or more networks.


The Generic Security Service Application Program Interface (defined in RFC-2743 published by The Internet Engineering Task Force) is a set of functions which provide security services. This API is used by clients and services to authenticate to each other without either program having specific knowledge of the underlying mechanism. If a network service (such as cyrus-IMAP) uses GSS-API, it can authenticate using Kerberos.


Also known as a hash value. A value generated by passing a string through a hash function. These values are typically used to ensure that transmitted data has not been tampered with.
hash function
A way of generating a digital "fingerprint" from input data. These functions rearrange, transpose or otherwise alter data to produce a hash value.


JAR file
A digital envelope for a compressed collection of files organized according to the Java™ archive (JAR) format.
Java™ archive (JAR) format
A set of conventions for associating digital signatures, installer scripts, and other information with files in a directory.
Java™ Native Interface (JNI)
A standard programming interface that provides binary compatibility across different implementations of the Java™ Virtual Machine (JVM) on a given platform, allowing existing code written in a language such as C or C++ for a single platform to bind to Java™. See
Java™ Security Services (JSS)
A Java™ interface for controlling security operations performed by Netscape Security Services (NSS).


A large number used by a cryptographic algorithm to encrypt or decrypt data. A person's public key, for example, allows other people to encrypt messages intended for that person. The messages must then be decrypted by using the corresponding private key.
Encrypted data cannot be decrypted without the proper key or extremely good fortune on the part of the cracker.
key distribution center
A service that issues Kerberos tickets, and which usually run on the same host as the ticket-granting server (TGS). Abbreviated KDC.
key exchange
A procedure followed by a client and server to determine the symmetric keys they will both use during an SSL session.
Key Exchange Algorithm (KEA)
An algorithm used for key exchange by the US Government.
A file that includes an unencrypted list of principals and their keys. Servers retrieve the keys they need from keytab files instead of using kinit. The default keytab file is /etc/krb5.keytab. The KDC administration server, /usr/kerberos/sbin/kadmind, is the only service that uses any other file (it uses /var/kerberos/krb5kdc/kadm5.keytab).
Also called key table.
The kinit command allows a principal who has already logged in to obtain and cache the initial ticket-granting ticket (TGT). Refer to the kinit man page for more information.


Lightweight Directory Access Protocol (LDAP)
A directory service protocol designed to run over TCP/IP and across multiple platforms. LDAP is a simplified version of Directory Access Protocol (DAP), used to access X.500 directories. LDAP is under IETF change control and has evolved to meet Internet requirements.


manual authentication
A way of configuring a Certificate System subsystem that requires human approval of each certificate request. With this form of authentication, a servlet forwards a certificate request to a request queue after successful authentication module processing. An agent with appropriate privileges must then approve each request individually before profile processing and certificate issuance can proceed.
A message digest algorithm that was developed by Ronald Rivest.

See Also one-way hash.


Network Security Services (NSS)
A set of libraries designed to support cross-platform development of security-enabled communications applications. Applications built using the NSS libraries support the Secure Sockets Layer (SSL) protocol for authentication, tamper detection, and encryption, and the PKCS #11 protocol for cryptographic token interfaces. NSS is also available separately as a software development kit.
The inability by the sender of a message to deny having sent the message. A digital signature provides one form of nonrepudiation.


object signing
A method of file signing that allows software developers to sign Java code, JavaScript scripts, or any kind of file and allows users to identify the signers and control access by signed code to local system resources.
Online Certificate Status Protocol.
one-way hash
1. A number of fixed-length generated from data of arbitrary length with the aid of a hashing algorithm. The number, also called a message digest, is unique to the hashed data. Any change in the data, even deleting or altering a single character, results in a different value.
2. The content of the hashed data cannot be deduced from the hash.
The specific operation, such as read or write, that is being allowed or denied in an access control instruction.
In the context of the certificate profile feature, it defines the resulting form from a successful certificate enrollment for a particular certificate profile. Each output is set, which then dynamically creates the form from all outputs configured for this enrollment.


password-based authentication
Confident identification by means of a name and password.

See Also authentication, certificate-based authentication.

PKCS #10
The public-key cryptography standard that governs certificate requests.
PKCS #11
The public-key cryptography standard that governs cryptographic tokens such as smart cards.
PKCS #11 module
A driver for a cryptographic device that provides cryptographic services, such as encryption and decryption, through the PKCS #11 interface. A PKCS #11 module, also called a cryptographic module or cryptographic service provider, can be implemented in either hardware or software. A PKCS #11 module always has one or more slots, which may be implemented as physical hardware slots in some form of physical reader, such as for smart cards, or as conceptual slots in software. Each slot for a PKCS #11 module can in turn contain a token, which is the hardware or software device that actually provides cryptographic services and optionally stores certificates and keys. Red Hat provides a built-in PKCS #11 module with Certificate System.
PKCS #12
The public-key cryptography standard that governs key portability.
The public-key cryptography standard that governs signing and encryption.
The principal is the unique name of a user or service allowed to authenticate using Kerberos. A principal follows the form root[/instance]@REALM. For a typical user, the root is the same as their login ID. The instance is optional. If the principal has an instance, it is separated from the root with a forward slash ("/"). An empty string ("") is considered a valid instance (which differs from the default NULL instance), but using it can be confusing. All principals in a realm have their own key, which for users is derived from a password or is randomly set for services.
Also called principal name.
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 encrypted with the corresponding public key.
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 certificate. It is typically used to encrypt data sent to the public key's owner, who then decrypts the data with the corresponding private key.
public-key cryptography
A set of well-established techniques and standards that allow an entity to verify its identity electronically or to sign and encrypt electronic data. Two keys are involved, a public key and a private key. A public key is published as part of a certificate, which associates that key with a particular identity. The corresponding private key is kept secret. Data encrypted with the public key can be decrypted only with the private key.
public-key infrastructure (PKI)
The standards and services that facilitate the use of public-key cryptography and X.509 v3 certificates in a networked environment.


RC2, RC4
Cryptographic algorithms developed for RSA Data Security by Rivest.

See Also cryptographic algorithm.

A network that uses Kerberos, composed of one or more servers called KDCs and a potentially large number of clients.
Red Hat Certificate System
A highly configurable set of software components and tools for creating, deploying, and managing certificates. Certificate System is comprised of five major subsystems that can be installed in different Certificate System instances in different physical locations: Certificate Manager, Online Certificate Status Manager, Data Recovery Manager, Token Key Service, and Token Processing System.

See enrollment.

root CA
The certificate authority (CA) with a self-signed certificate at the top of a certificate chain.

See Also CA certificate.

RSA algorithm
Short for Rivest-Shamir-Adleman, a public-key algorithm for both encryption and authentication. It was developed by Ronald Rivest, Adi Shamir, and Leonard Adleman and introduced in 1978.
RSA key exchange
A key-exchange algorithm for SSL based on the RSA algorithm.


Secure Sockets Layer (SSL)
A protocol that allows mutual authentication between a client and server and the establishment of an authenticated and encrypted connection. SSL runs above TCP/IP and below HTTP, LDAP, IMAP, NNTP, and other high-level network protocols.
server authentication
The process of identifying a server to a client.

See Also client authentication.

server SSL certificate
A certificate used to identify a server to a client using the Secure Sockets Layer (SSL) protocol.
A program accessed over the network.
Java™ code that handles a particular kind of interaction with end entities on behalf of a Certificate System subsystem. For example, certificate enrollment, revocation, and key recovery requests are each handled by separate servlets.
Secure Hash Algorithm, a hash function used by the US government.
signature algorithm
A cryptographic algorithm used to create digital signatures. Certificate System supports the MD5 and SHA-1 signing algorithms.

See Also cryptographic algorithm, digital signature.

signing certificate
A certificate that's public key corresponds to a private key used to create digital signatures. For example, a Certificate Manager must have a signing certificate that's public key corresponds to the private key it uses to sign the certificates it issues.
signing key
A private key used for signing only. A signing key and its equivalent public key, plus an encryption key and its equivalent public key, constitute a dual key pair.
single sign-on
1. In Certificate System, a password that simplifies the way to sign on to Red Hat Certificate System by storing the passwords for the internal database and tokens. Each time a user logs on, he is required to enter this single password.
2. The ability for a user to log in once to a single computer and be authenticated automatically by a variety of servers within a network. Partial single sign-on solutions can take many forms, including mechanisms for automatically tracking passwords used with different servers. Certificates support single sign-on within a public-key infrastructure (PKI). A user can log in once to a local client's private-key database and, as long as the client software is running, rely on certificate-based authentication to access each server within an organization that the user is allowed to access.
The portion of a PKCS #11 module, implemented in either hardware or software, that contains a token.
smart card
A small device that contains a microprocessor and stores cryptographic information, such as keys and certificates, and performs cryptographic operations. Smart cards implement some or all of the PKCS #11 interface.

See Secure Sockets Layer (SSL).

The entity identified by a certificate. In particular, the subject field of a certificate contains a subject name that uniquely describes the certified entity.
subject name
A distinguished name (DN) that uniquely describes the subject of a certificate.
symmetric encryption
An encryption method that uses the same cryptographic key to encrypt and decrypt a given message.


A temporary set of electronic credentials that verify the identity of a client for a particular service. Also called credentials.
ticket-granting server (TGS)
A server that issues tickets for a desired service which are in turn given to users for access to the service. The TGS usually runs on the same host as the KDC.
ticket-granting ticket (TGT)
A special ticket that allows the client to obtain additional tickets without applying for them from the KDC.
A hardware or software device that is associated with a slot in a PKCS #11 module. It provides cryptographic services and optionally stores certificates and keys.
Confident reliance on a person or other entity. In a public-key infrastructure (PKI), trust refers to the relationship between the user of a certificate and the certificate authority (CA) that issued the certificate. If a CA is trusted, then valid certificates issued by that CA can be trusted.


virtual private network (VPN)
A way of connecting geographically distant divisions of an enterprise. The VPN allows the divisions to communicate over an encrypted channel, allowing authenticated, confidential transactions that would normally be restricted to a private network.

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