A dictionary attack is a technique for spying on passwords or encrypted messages. In this technique, crackers use words from a dictionary to crack the password or decrypt encrypted document
. The dictionaries list common words, but also newly created meaningful letter combinations. In the case of passwords, the word list attack may fail if passphrases are used instead of passwords. Promising dictionary attacks can be reduced or avoided by a short fixed input time or by a fixed number of input attempts. When decrypting
large documents, the word list method is extremely time consuming. Word list attacks can also be used by spammers for spamming.
The spammer enters arbitrary name combinations with full or shortened first name and last name as address and sends thousands and thousands of mails in the justified hope that one or the other will reach an e-mail user. Other attack techniques for cracking passwords are the brute force attack and the rainbow table.