Difference Between Brute Force and Dictionary Attack

Brute Force Attack and Dictionary Attack are both methods of cyber security attacks. The attacker attempts to log in to a user’s account by systematic trials of key combinations and potential passwords until the correct one is found. Cyber security attackers recognize and record the habits of unsavvy users and use them in their favor to gain access to people’s profiles online and offline.

Brute Force vs Dictionary Attack

The main difference between brute force and dictionary attack is that a Brute Force attack is when there is the use of ‘brute force, or an innumerable number of key combinations to essentially ‘guess’ a password. On the other hand, A Dictionary Attack is when the attacker enters passwords from a predefined list consisting of probable passwords. 

Brute Force vs Dictionary Attack

Brute Force attack is a method of cryptographic hacking that involves attaining unauthorized access to login information or encryption keys by probing the entire keyspace of the algorithm through the process of trial and error. As this is an exhaustive task that does not require any intellectual involvement, therefore, generally, tools are used to carry out the job.

Dictionary Attack is one form of brute force attack that takes advantage of the unsavvy users who use nonunique passcodes. Here, the intruder uses a list of common words or phrases potentially used by individuals and businesses as passwords to gain access to protected computers, networks, or other IT resources.

Comparison Table Between Brute Force and Dictionary Attack

Parameters of ComparisonBrute ForceDictionary Attack
DefinitionThe attacker attempts all possible combinations of passcodes.The attacker uses a precompiled list of known passcodes.
EffectivenessBrute Force is more effective if the passcode is a short one.Dictionary Attack is more effective if the passcode is a commonly used one.
Factors Influencing TimeThe time taken depends on the length and strength of the passcode.The time taken depends on the length of the dictionary.
Number of KeysA large number of key combinations are involved.This is limited to only a certain number of keys.
Primary UtilityThis is generally used for attacking encryption algorithms.This is generally used for attacking passwords.
Chances of SuccessBound to be successful.It may not be successful.

What is Brute Force?

Cyber security attackers have a plethora of tools available at their disposal that attempt every possible combination of numbers, letters, and special characters and sooner or later guess the correct password and assist them in breaching a user’s privacy. These tools can be programmed to include or exclude letters, numbers, and symbols as per the protocols of password formation of the organization provided that the attacker is aware of them. Advanced Brute Force attacks often make crack passwords out of sequence by making certain assumptions when attacking.

For instance: the first character is more likely to be uppercase, etc. The vulnerability of a password to such an attack involving brute force depends on the length of the password. A four-digit pin might take less than a minute to be cracked. A six-character password might take an hour. Eight characters, including letters and special characters, may prolong the process for days. With each new character added, the strength and subsequently the amount of time taken to crack it increases exponentially. However, it should be considered that no matter the length and strength, every password is vulnerable to this nature of an attack and subject to the conditions of sufficient and efficient computing power and the dedication of the attacker, it is only a matter of time before the password is eventually unveiled. A password could be so long that it takes years to crack under a brute force attack, but if kept at it, crack it will.

What is Dictionary Attack?

Dictionary Attacks work on the basic principle that most users, either due to unwillingness or failure to remember passwords, resort to using generic words from an existing language and typical password trends to secure their data and devices. A Dictionary Attack is based on an inventory of oft-used passphrases. Initially, these attacks utilized words found in a dictionary, hence its name. But nowadays, endless lists of possible passcodes are openly found on the internet that is made of passcodes obtained from previously made successful security breaches. (like ‘password’, ‘thepasswordis1234’, ‘1234…’, ‘letmein’, etc.) and passwords that have previously been used in other websites (in case the user has reused passwords).

The dictionary is created by examining trends and patterns observed among users while creating passwords. They might even include crucial information about the target (birthdays, anniversaries, pets’ names, etc.). Dictionary Attack is an effective method of attack on passwords that are based on simple words. However, most modern systems prohibit and prevent their users from setting such simple passwords and compel them to create stronger and more unique ones that won’t be found on a wordlist. The time is taken to attempt the break-in, and its chances of success depend on the dictionary’s exhaustivity.

Main Differences Between Brute Force and Dictionary Attack

  1. In a Brute Force attack, there is a systematic pathway where each character of a passcode, pin, etc., is cracked independently by software subject to the stipulations followed during the password formation that determines the extent of the keyspace. In Dictionary Attack, the software undertakes a method of trial and error to determine the full password.
  2. In terms of effectiveness, brute force is more effective when the password is short. This is because otherwise, depending on the number of characters, a brute force attack can take between less than a minute to several years for a password to be cracked. Whereas, if the password is a commonly used one or uses a standard template, a dictionary is more likely to have it, making dictionary attacks more effective.
  3. The amount of time required for a Brute Force attack to crack a code is dependent on the length of the code because this method guesses every character of the passcode individually. In the case of Dictionary Attack, the time is shorter because it addresses the entire passcode at once.
  4. Brute Force comes in handy when the keyspace of the algorithm to be cracked is expansive, and a more significant number of key combinations and permutations are involved. Dictionary Attacks are the way to go when addressing passwords where the keyspace is much smaller, and there are definite patterns in the passwords.
  5. Brute Force attacks are primarily used for attacking encryption algorithms because these are generally made of random series of numbers. Dictionary Attacks are mainly used to attack and crack passwords because they usually contain words and patterns that an encyclopedic dictionary can crack. 
  6. Brute Force attacks are bound to be successful given sufficient time. However, it is pertinent to mention that adequate can mean anything between a few seconds to a lifetime. The success of a Dictionary Attack depends on the comprehensiveness of the dictionary.


After considering everything, it can be concluded that while Brute Force attack and Dictionary Attack are both popular methods of a cyber security breach, their mode of operation, purposes, duration of the process, and rate of success vary greatly and are influenced by a lot of factors. Brute Force attack undertakes the task character by character, is better intended for encryption algorithms, may take any amount of time, and is widely successful in fulfilling its purpose subject to the time factor. Dictionary Attack carries out the job password by password, is more beneficial for passcode breaking, can take only as much time as it takes to try all the words in the dictionary, and may not always be successful.


  1. https://ieeexplore.ieee.org/abstract/document/8400211
  2. https://onlinelibrary.wiley.com/doi/abs/10.4218/etrij.09.0209.0137
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