An Iranian hacker has claimed responsibility for the recent security breach at certification authority Comodo Group.

Comodo had said last week it had to revoke nine digital certificates for its Web service providers including Google, Microsoft, Skype and Yahoo after it found out that a hacker had issued those certificates. Investigations had traced the attack to Iran.

The individual claiming to be the hacker said that he was a 21-year-old software engineering student in Iran and was working alone with no intervention form the government of Iran.

In a series of messages in flawed English on website Pastebin.com, the hacker wrote how he conducted the attack and boasted about his knowledge and experience.

Calling himself "comodohacker," he wrote, "I know you are really shocked about my knowledge, my skill, my speed, my expertise and entire attack. That’s okay, all of it was so easy for me."

"I’m a single hacker with the experience of 1000 hackers. I’m a single programmer with the experience of 1000 programmers."

The hacker also said that his attack was in revenge for the Stuxnet virus attack on Iran’s nuclear programme.

He wrote, "When USA and Israel creates Stuxnet, nobody talks about it, nobody blamed, nothing happened at all, so when I sign certificates nothing should happen, I say that, when I sign certificates nothing should happen."