A Fort Knox for Web crypto keys: Inside Symantecs SSL certificate vault
arstechnica.com/security/2012/11/inside-symantecs-ssl-certificate-vault
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
As he negotiates a series of additional mazes inside, he comes upon still more security checkpoints. One room at the center of the buildinginside two concentric squares protected by a double layer of metallic mesh that isn't easily drilled, cut, or welded, requires two authorized Symantec employees to enter. To enter, Meijer and a colleague must key in a PIN and show a fingerprint. Inside are cabinets housing special-purpose computer servers that neither of the two employees can open because the combination is held by a different class of employees. A separate room where digital certificates are generated under rigorous "key-signing ceremonies," also requires dual occupancy. To further ensure the security of the operation, the second employee who must accompany Meijer is one of fewer than two dozen people with the required access codes.