System Administration Guide: Security Services

proxiable ticket

A ticket that can be used by a service on behalf of a client to perform an operation for the client. Thus, the service is said to act as the client's proxy. With the ticket, the service can take on the identity of the client. The service can use a proxiable ticket to obtain a service ticket to another service, but it cannot obtain a ticket-granting ticket. The difference between a proxiable ticket and a forwardable ticket is that a proxiable ticket is only valid for a single operation. See also forwardable ticket.

public-key encryption

An encryption scheme in which each user has two keys, one public key and one private key. In public-key encryption, the sender uses the receiver's public key to encrypt the message, and the receiver uses a private key to decrypt it. SEAM is a private-key system. See also private-key encryption.

QOP

Quality of Protection. A parameter that is used to select the cryptographic algorithms that are used in conjunction with the integrity service or privacy service.

RBAC

Role-Based Access Control. An alternative to the all-or-nothing superuser model. RBAC lets an organization separate superuser's capabilities and assign them to special user accounts called roles. Roles can be assigned to specific individuals, according to their job needs.

realm

1. The logical network that is served by a single SEAM database and a set of Key Distribution Centers (KDCs).

2. The third part of a principal name. For the principal name joe/admin@ENG.EXAMPLE.COM, the realm is ENG.EXAMPLE.COM. See also principal name.

relation

A configuration variable or relationship that is defined in the kdc.conf or krb5.conf files.

renewable ticket

Because having tickets with very long lives is a security risk, tickets can be designated as renewable. A renewable ticket has two expiration times: a) the time at which the current instance of the ticket expires, and b) maximum lifetime for any ticket. If a client wants to continue to use a ticket, the client renews the ticket before the first expiration occurs. For example, a ticket can be valid for one hour, with all tickets having a maximum lifetime of ten hours. If the client that holds the ticket wants to keep it for more than an hour, the client must renew the ticket. When a ticket reaches the maximum ticket lifetime, it automatically expires and cannot be renewed.

rights profile

Also referred to as right or profile. A collection of overrides used in RBAC that can be assigned to a role or user. A rights profile can consist of authorizations, commands with set UIDs or GIDs, which are referred to as security attributes, and other rights profiles.

role

A special identity for running privileged applications that only assigned users can assume.

SEAM

Sun Enterprise Authentication Mechanism. A system for authenticating users over a network, based on the Kerberos V5 technology that was developed at the Massachusetts Institute of Technology.

"SEAM" and "Kerberos" are often used interchangeably in the SEAM documentation.

secret key

See private key.

Secure Shell

A special protocol for secure remote login and other secure network services over an insecure network.

security flavor

See flavor.

security mechanism

See mechanism.

security service

See service.

server

A principal that provides a resource to network clients. For example, if you rlogin to the machine boston.eng.acme.com, then that machine is the server that provides the rlogin service. See also service principal.

server principal

(RPCSEC_GSS API) A principal that provides a service. The server principal is stored as an ASCII string in the form service@host. See also client principal.

service

1. A resource that is provided to network clients, often by more than one server. For example, if you rlogin to the machine boston.eng.example.com, then that machine is the server that provides the rlogin service.

2. A security service (either integrity or privacy) that provides a level of protection beyond authentication. See also integrity and privacy.

service key

An encryption key that is shared by a service principal and the KDC, and is distributed outside the bounds of the system. See also key.

service principal

A principal that provides Kerberos authentication for a service or services. For service principals, the primary name is a name of a service, such as ftp, and its instance is the fully qualified host name of the system that provides the service. See also host principal, user principal.

session key

A key that is generated by the authentication service or the ticket-granting service. A session key is generated to provide secure transactions between a client and a service. The lifetime of a session key is limited to a single login session. See also key.

slave KDC

A copy of a master KDC, which is capable of performing most functions of the master. Each realm usually has several slave KDCs (and only one master KDC). See also KDC, master KDC.

stash file

A stash file contains an encrypted copy of the master key for the KDC. This master key is used when a server is rebooted to automatically authenticate the KDC before it starts the kadmind and krb5kdc processes. Because the stash file includes the master key, the stash file and any backups of it should be kept secure. If the encryption is compromised, then the key could be used to access or modify the KDC database.


	proxiable ticket A ticket that can be used by a service on behalf of a client to perform an operation for the client. Thus, the service is said to act as the client's proxy. With the ticket, the service can take on the identity of the client. The service can use a proxiable ticket to obtain a service ticket to another service, but it cannot obtain a ticket-granting ticket. The difference between a proxiable ticket and a forwardable ticket is that a proxiable ticket is only valid for a single operation. See also forwardable ticket. public-key encryption An encryption scheme in which each user has two keys, one public key and one private key. In public-key encryption, the sender uses the receiver's public key to encrypt the message, and the receiver uses a private key to decrypt it. SEAM is a private-key system. See also private-key encryption. QOP Quality of Protection. A parameter that is used to select the cryptographic algorithms that are used in conjunction with the integrity service or privacy service. RBAC Role-Based Access Control. An alternative to the all-or-nothing superuser model. RBAC lets an organization separate superuser's capabilities and assign them to special user accounts called roles. Roles can be assigned to specific individuals, according to their job needs. realm 1. The logical network that is served by a single SEAM database and a set of Key Distribution Centers (KDCs). 2. The third part of a principal name. For the principal name `joe/admin@ENG.EXAMPLE.COM`, the realm is `ENG.EXAMPLE.COM`. See also principal name. relation A configuration variable or relationship that is defined in the `kdc.conf` or `krb5.conf` files. renewable ticket Because having tickets with very long lives is a security risk, tickets can be designated as renewable. A renewable ticket has two expiration times: a) the time at which the current instance of the ticket expires, and b) maximum lifetime for any ticket. If a client wants to continue to use a ticket, the client renews the ticket before the first expiration occurs. For example, a ticket can be valid for one hour, with all tickets having a maximum lifetime of ten hours. If the client that holds the ticket wants to keep it for more than an hour, the client must renew the ticket. When a ticket reaches the maximum ticket lifetime, it automatically expires and cannot be renewed. rights profile Also referred to as right or profile. A collection of overrides used in RBAC that can be assigned to a role or user. A rights profile can consist of authorizations, commands with set UIDs or GIDs, which are referred to as security attributes, and other rights profiles. role A special identity for running privileged applications that only assigned users can assume. SEAM Sun Enterprise Authentication Mechanism. A system for authenticating users over a network, based on the Kerberos V5 technology that was developed at the Massachusetts Institute of Technology. "SEAM" and "Kerberos" are often used interchangeably in the SEAM documentation. secret key See private key. Secure Shell A special protocol for secure remote login and other secure network services over an insecure network. security flavor See flavor. security mechanism See mechanism. security service See service. server A principal that provides a resource to network clients. For example, if you `rlogin` to the machine `boston.eng.acme.com`, then that machine is the server that provides the `rlogin` service. See also service principal. server principal (RPCSEC_GSS API) A principal that provides a service. The server principal is stored as an ASCII string in the form service`@`host. See also client principal. service 1. A resource that is provided to network clients, often by more than one server. For example, if you `rlogin` to the machine `boston.eng.example.com`, then that machine is the server that provides the `rlogin` service. 2. A security service (either integrity or privacy) that provides a level of protection beyond authentication. See also integrity and privacy. service key An encryption key that is shared by a service principal and the KDC, and is distributed outside the bounds of the system. See also key. service principal A principal that provides Kerberos authentication for a service or services. For service principals, the primary name is a name of a service, such as `ftp`, and its instance is the fully qualified host name of the system that provides the service. See also host principal, user principal. session key A key that is generated by the authentication service or the ticket-granting service. A session key is generated to provide secure transactions between a client and a service. The lifetime of a session key is limited to a single login session. See also key. slave KDC A copy of a master KDC, which is capable of performing most functions of the master. Each realm usually has several slave KDCs (and only one master KDC). See also KDC, master KDC. stash file A stash file contains an encrypted copy of the master key for the KDC. This master key is used when a server is rebooted to automatically authenticate the KDC before it starts the `kadmind` and `krb5kdc` processes. Because the stash file includes the master key, the stash file and any backups of it should be kept secure. If the encryption is compromised, then the key could be used to access or modify the KDC database.