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Password-based Cryptography
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. Techniques to mitigate such attack include passphrases and iterated (deliberately slow) password-based key derivation functions such as PBKDF2 (RFC 2898). Multi-party methods Password-authenticated key agreement 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 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 *Passphrase *Password-authenticated key agreement In cryptography, a password- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 one is found. Alternatively, the attacker can attempt to guess the key which is typically created from the password using a key derivation function. This is known as an exhaustive key search. A brute-force attack is a cryptanalytic attack that can, in theory, be used to attempt to decrypt any encrypted data (except for data encrypted in an information-theoretically secure manner). Such an attack might be used when it is not possible to take advantage of other weaknesses in an encryption system (if any exist) that would make the task easier. When password-guessing, this method is very fast when used to check all short passwords, but for longer passwords other methods such as the dictionary attack are used because a brute-force search ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 both access to, and the operation of, cryptographic programs and systems, especially those that derive an encryption key from a passphrase. The origin of the term is by analogy with ''password''. The modern concept of passphrases is believed to have been invented by Sigmund N. Porter in 1982. Security Considering that the entropy of written English is less than 1.1 bits per character, passphrases can be relatively weak. NIST has estimated that the 23-character passphrase "IamtheCapitanofthePina4" contains a 45-bit strength. The equation employed here is: : 4 bits (1st character) + 14 bits (characters 2–8) + 18 bits (characters 9–20) + 3 bits (characters 21–23) + 6 bits (bonus for upper case, lower case, and alphanumeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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' Public-Key Cryptography Standards (PKCS) series, specifically PKCS#5 v2.0, also published as Internet Engineering Task Force's RFC2898. It supersedes PBKDF1, which could only produce derived keys up to 160 bits long. RFC8018 (PKCS#5 v2.1), published in 2017, recommends PBKDF2 for password hashing. Purpose and operation PBKDF2 applies a pseudorandom function, such as hash-based message authentication code (HMAC), to the input password or passphrase along with a salt value and repeats the process many times to produce a ''derived key'', which can then be used as a cryptographic key in subsequent operations. The added computational work makes password cracking much more difficult, and is known as key stretching. When the standard was writte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 man-in-the-middle cannot obtain enough information to be able to brute-force guess a password without further interactions with the parties for each (few) guesses. This means that strong security can be obtained using weak passwords. Types Password-authenticated key agreement generally encompasses methods such as: * Balanced password-authenticated key exchange * Augmented password-authenticated key exchange * Password-authenticated key retrieval * Multi-server methods * Multi-party methods In the most stringent password-only security models, there is no requirement for the user of the method to remember any secret or public data other than the password. Password-authenticated key exchange (PAKE) is a method in which two or more parties, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 challenge–response protocol is password authentication, where the challenge is asking for the password and the valid response is the correct password. An adversary who can eavesdrop on a password authentication can then authenticate itself by reusing the intercepted password. One solution is to issue multiple passwords, each of them marked with an identifier. The verifier can then present an identifier, and the prover must respond with the correct password for that identifier. Assuming that the passwords are chosen independently, an adversary who intercepts one challenge–response message pair has no clues to help with a different challenge at a different time. For example, when other communications security methods are unavailable, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 password-protected services that a typical individual accesses can make memorization of unique passwords for each service impractical. Using the terminology of the NIST Digital Identity Guidelines, the secret is held by a party called the ''claimant'' while the party verifying the identity of the claimant is called the ''verifier''. When the claimant successfully demonstrates knowledge of the password to the verifier through an established authentication protocol, the verifier is able to infer the claimant's identity. In general, a password is an arbitrary string of characters including letters, digits, or other symbols. If the permissible characters are constrained to be numeric, the corresponding secret is sometimes called a personal i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 both access to, and the operation of, cryptographic programs and systems, especially those that derive an encryption key from a passphrase. The origin of the term is by analogy with ''password''. The modern concept of passphrases is believed to have been invented by Sigmund N. Porter in 1982. Security Considering that the entropy of written English is less than 1.1 bits per character, passphrases can be relatively weak. NIST has estimated that the 23-character passphrase "IamtheCapitanofthePina4" contains a 45-bit strength. The equation employed here is: : 4 bits (1st character) + 14 bits (characters 2–8) + 18 bits (characters 9–20) + 3 bits (characters 21–23) + 6 bits (bonus for upper case, lower case, and alphanumeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
