The certificate plays an essential part in keeping the immense LAUSD network secure, which is why you need to have it installed on whichever device you use to connect to the LAUSD network. Occasionally, the root certificate will be updated by ITD to keep up with changes in security, in which case you might start seeing the following warning when visiting your favorite sites:
If you haven't already, visit achieve.lausd.net/rootcertificate to download the latest certificate onto your system, and acquire full access to the LAUSD network.