Core (spring-security-core): Spring security's core classes and interfaces on authentication and access control reside here.

Remoting (spring-security-remoting): In case you need Spring Remoting, this is the module with the necessary classes.

Aspect (spring-security-aspects): Aspect-Oriented Programming (AOP) support within Spring Security.

Config (spring-security-config): Provides XML and Java configuration support.

Crypto (spring-security-crypto): Contains cryptography support.

Data (spring-security-data): Integration with Spring Data.

Messaging (spring-security-messaging)

OAuth2: Support for OAuth 2.x support within Spring Security:

Core (spring-security-oauth2-core)

Client (spring-security-oauth2-client)

JOSE (spring-security-oauth2-jose)

OpenID (spring-security-openid): OpenID web-authentication support.

CAS (spring-security-cas): CAS (Central Authentication Service) client integration.

TagLib (spring-security-taglibs): Various tag libraries regarding Spring Security.

Test (spring-security-test): Testing support.

Web (spring-security-web): Contains web security infrastructure code, such