[3] The existing techniques of identity delegation using sudo or su commands of UNIX are very popular.
[citation needed] To use the sudo command, a person first has to start his session with his own original identity.
It requires the delegated account password or explicit authorizations granted by the system administrator.
[4] The most common way of ensuring computer security is access control mechanisms provided by operating systems such as UNIX, Linux, Windows, Mac OS, etc.
This may cause the denial of service, which is very undesirable in some environments, such as in safety critical systems or in health care.