Acegi SecturityはSpring Securityに名称が変わってるんだね。
Springの名がつく通り、公式のプロダクトになってます。
Acegi Security is now Spring Security, the official security project of the Spring Portfolio. If you are planning a new project, we'd recommend you consider using Spring Security. Acegi Security 1.0.7 will be the last non-critical release of the 1.0.x series.
Acegi Security - Acegi Security System for Spring
