Password-based cryptography generally refers to two distinct classes of methods:
*Single-party methods
*Multi-party methods
Single party methods
Some systems attempt to derive a cryptographic key directly from a password. However, such practice is generally ill-advised when there is a threat of
brute-force attack
In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correct ...
. Techniques to mitigate such attack include
passphrase
A passphrase is a sequence of words or other text used to control access to a computer system, program or data. It is similar to a password in usage, but a passphrase is generally longer for added security. Passphrases are often used to control ...
s and iterated (deliberately slow) password-based key derivation functions such as
PBKDF2
In cryptography, PBKDF1 and PBKDF2 (Password-Based Key Derivation Function 1 and 2) are key derivation functions with a sliding computational cost, used to reduce vulnerabilities of brute-force attacks.
PBKDF2 is part of RSA Laboratories' Publ ...
(RFC 2898).
Multi-party methods
Password-authenticated key agreement In cryptography, a password-authenticated key agreement method is an interactive method for two or more parties to establish cryptographic keys based on one or more party's knowledge of a password.
An important property is that an eavesdropper or m ...
systems allow two or more parties that agree on a password (or password-related data) to derive shared keys without exposing the password or keys to network attack. Earlier generations of
challenge–response authentication
In computer security, challenge–response authentication is a family of protocols in which one party presents a question ("challenge") and another party must provide a valid answer ("response") to be authenticated.
The simplest example of a ch ...
systems have also been used with passwords, but these have generally been subject to eavesdropping and/or brute-force attacks on the password.
See also
*
Password
A password, sometimes called a passcode (for example in Apple devices), is secret data, typically a string of characters, usually used to confirm a user's identity. Traditionally, passwords were expected to be memorized, but the large number of ...
*
Passphrase
A passphrase is a sequence of words or other text used to control access to a computer system, program or data. It is similar to a password in usage, but a passphrase is generally longer for added security. Passphrases are often used to control ...
*
Password-authenticated key agreement In cryptography, a password-authenticated key agreement method is an interactive method for two or more parties to establish cryptographic keys based on one or more party's knowledge of a password.
An important property is that an eavesdropper or m ...
{{DEFAULTSORT:Password-Based Cryptography
Cryptography