Sanakirjahyökkäyksen

Sanakirjahyökkäys, known in English as a dictionary attack, is a type of brute-force cryptanalysis or password-cracking technique. It involves systematically trying a large set of predefined words and phrases as potential passwords or keys. These words are typically sourced from dictionaries, common password lists, or commonly used phrases. The attacker generates a list of potential passwords and then tests each one against the target system or encrypted data.

Unlike a purely random brute-force attack, which tries every possible combination of characters, a dictionary attack is more efficient because it focuses on more probable password candidates. Attackers often combine dictionary words with common substitutions (e.g., replacing 'a' with '@', 'i' with '1'), number appends (e.g., appending '123' or birth years), or common prefixes and suffixes. The effectiveness of a dictionary attack depends heavily on the strength of the password being targeted. If a password consists of a dictionary word with no modifications, it can be cracked very quickly.

To defend against dictionary attacks, users are advised to create strong, complex passwords that are not easily guessable. This includes using a combination of uppercase and lowercase letters, numbers, and special characters, and avoiding common words or personal information. Password hashing algorithms that incorporate salting, which adds a random string to each password before hashing, also significantly hinder dictionary attacks by making precomputed rainbow tables ineffective.