C2 LevelSecurity is a US government security standard described in the Orange Book
. C2 was defined by the National Computer Security Center (NCSC) and indicates an increased security standard for confidential data in computer systems. C2 primarily targets the access authorization and logon procedures and includes the computer hardware and operating system. The C2 security standard is set at a low level and prevents, among other things, programs from being started without a password request. The access procedure is logged.