Lockheed Martin, the nation’s largest military contractor, has battled disruptions in its computer networks this week that might be tied to a hacking attack on a vendor that supplies coded security tokens to millions of users, security officials said on Friday.

The SecurID electronic tokens, which are used to gain access to computer networks by corporate employees and government officials from outside their offices, are supplied by the RSA Security division of the EMC Corporation.

RSA acknowledged in March that it had sustained a data breach that could have compromised some of its security products. Executives in the military industry said Friday that Lockheed’s problems appeared to stem from that data breach and could be the first public signs of damage from it.

The March intrusion reverberated through the computer security community. The RSA technology is used by most Fortune 500 companies and federal agencies to provide an extra layer of security when employees use their networks from customer offices, hotels or their homes.