apt-get install tor를 사용하여 tor를 설치할 수 없습니다.

kali linux 2017에 tor를 설치하려고 하면 다음과 같이 표시됩니다.

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package tor is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'tor' has no installation candidate