Comodo CA issued in 2011 certificates for major websites such
as Google, Yahoo, Mozilla and Skype to an Iranian hacker [4]. The DigiNotar CA in the
Netherlands was also removed as a trusted CA in most major browsers after issuing a Google
certifi cate to a third party. Whether these incidents are the result of sophisticated attacks or
poor security policies is irrelevant. The fact is that countries cannot just rely on the security
of their own PKI infrastructures (or that of their allies). NATO can usually audit its own CA
infrastructures and ensure their security. However, security breaches in an external CA can also
jeopardize NATO own security. In addition, the possibility of malicious use of intermediate
CAs to perform targeted attacks through ad-hoc certificates cannot be neglected [5], and these
attacks are extremely difficult to detect. These rogue certificates can be used in man-in-the-middle
attacks, which will not be detected by conventional mechanisms for PKIX certification
path validation and revocation checks.