is a hacking tool created by the Cult of the Deac Cow (cDc). Goolag Scanner scans more than 1000 vulnerabilities of a web site. The scanning is not performed directly but through queries to Google. Thus, the web site is not aware that it is been scanned.
Guessed plain text attack
Having the cipher text, the hacker guesses the might plain text. By checking the encryption with the public key, he can verify his assumption. The counter measure is to add some random bits to the message.