Is it possible to have APT accept an “invalid” certificate?

I had discovered something funny today. So, I have Kali Linux and I am trying to fully update the system using the repo http://http.kali.org/kali. All is good and well until I get 403 denied for backdoor-factory and mimikatz. At first I thought it was a server configuration error and so ignored it, but then I got curious and decided to pop the URLs into Firefox. Sure enough, my university blocks these specific URLs, but not anything else in the repo.