Certificate Transparency

On August 28, 2011, a mis-issued wildcard HTTPS certificate for google.com was used to conduct a man-in-the-middle attack against multiple users in Iran. The certificate had been issued by a Dutch CA (certificate authority) known as DigiNotar, a subsidiary of VASCO Data Security International. Later analysis showed that DigiNotar had been aware of the breach in its systems for more than a month - since at least July 19.

It also showed that at least 531 fraudulent certificates had been issued. The final count may never be known, since DigiNotar did not have records of all the mis-issued certificates. On September 20, 2011, DigiNotar was declared bankrupt.