Java Authentication and Authorization Service


Java Authentication and Authorization Service, or JAAS, pronounced "Jazz", is the Java implementation of the standard Pluggable Authentication Module information security framework.
JAAS was introduced as an extension library to the Java Platform, Standard Edition 1.3 and was integrated in version 1.4.
JAAS has as its main goal the separation of concerns of user authentication so that they may be managed independently. While the former authentication mechanism contained information about where the code originated from and who signed that code, JAAS adds a marker about who runs the code. By extending the verification vectors JAAS extends the security architecture for Java applications that require authentication and authorization modules.

Administration

For the system administrator, JAAS consists of two kinds of configuration file:
For example, an application may have this login.conf file indicating how different authentication mechanisms are to be run to authenticate the user:
PetShopApplication

Application interface

For the application developer, JAAS is a standard library that provides:
For the security system integrator, JAAS provides interfaces:
Login modules are primarily concerned with authentication rather than authorization and form a widely used component of JAAS. A login module is required to implement the javax.security.auth.spi.LoginModule interface, which specifies the following methods:
Note: A Subject is the user that is attempting to log in.
Login modules can provide single sign on via a particular SSO protocol/framework, can check for the presence of hardware security tokens, etc. In an n-tier application, LoginModules can be present on both the client side and server side.

LoginModule (javax.security.auth.spi.LoginModule)

Login modules are written by implementing this interface; they contain the actual code for authentication. It can use various mechanisms to authenticate user credentials. The code could retrieve a password from a database and compare it to the password supplied to the module.

LoginContext (javax.security.auth.login.LoginContext)

The login context is the core of the JAAS framework which kicks off the authentication process by creating a Subject. As the authentication process proceeds, the subject is populated with various principals and credentials for further processing.

Subject (javax.security.auth.Subject)

A subject represents a single user, entity or system –in other words, a client– requesting authentication.

Principal (java.security.Principal)

A principal represents the face of a subject. It encapsulates features or properties of a subject. A subject can contain multiple principals.

Credentials

Credentials are nothing but pieces of information regarding the subject in consideration. They might be account numbers, passwords, certificates etc. As the credential represents some important information, the further interfaces might be useful for creating a proper and secure credential – javax.security.auth.Destroyable and javax.security.auth.Refreshable. Suppose that after the successful authentication of the user you populate the subject with a secret ID with which the subject can execute some critical services, but the credential should be removed after a specific time. In that case, one might want to implement the Destroyable interface. Refreshable might be useful if a credential has only a limited timespan in which it is valid.

Form Authentication

Form authentication is another commonly used part of JAAS. In this process the user is typically presented with a web page containing a form asking for a username and password. This data is then submitted via POST to a URL containing the text j_security_check, e.g. www.example.com/j_security_check. The credentials are checked on the server side and a session ID is returned to the client via a cookie. This authentication method is flexible in that a Java HTTP client such as Apache HTTP client can be used in place of a web-browser, e.g. in a desktop application, as long as the following standard steps are followed:
Additional assertions can be added to the above process.