Unix crypt(3)
E721424
Unix crypt(3) is a traditional Unix library function and algorithm used to hash and verify passwords, historically based on modified DES and later extended to support stronger schemes.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Unix crypt(3) canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T8248328 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
Target entity: Unix crypt(3) Context triple: [John the Ripper, supportsHashType, Unix crypt(3)]
-
A.
CRYPTO
CRYPTO is a premier international research conference focused on cryptology and information security, organized annually by the International Association for Cryptologic Research.
-
B.
CRAM-MD5
CRAM-MD5 is a challenge–response authentication mechanism that uses MD5 hashing to securely verify a user's identity without transmitting their password in plaintext.
-
C.
John the Ripper
John the Ripper is a widely used open-source password cracking tool designed for security auditing and penetration testing.
-
D.
PBKDF2
PBKDF2 is a key derivation function that strengthens passwords by applying repeated hashing with a salt to produce cryptographic keys resistant to brute-force attacks.
-
E.
Lucifer cipher
The Lucifer cipher is an early block cipher developed at IBM by Horst Feistel that served as a foundational design precursor to the Data Encryption Standard (DES).
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
Target entity: Unix crypt(3) Target entity description: Unix crypt(3) is a traditional Unix library function and algorithm used to hash and verify passwords, historically based on modified DES and later extended to support stronger schemes.
-
A.
CRYPTO
CRYPTO is a premier international research conference focused on cryptology and information security, organized annually by the International Association for Cryptologic Research.
-
B.
CRAM-MD5
CRAM-MD5 is a challenge–response authentication mechanism that uses MD5 hashing to securely verify a user's identity without transmitting their password in plaintext.
-
C.
John the Ripper
John the Ripper is a widely used open-source password cracking tool designed for security auditing and penetration testing.
-
D.
PBKDF2
PBKDF2 is a key derivation function that strengthens passwords by applying repeated hashing with a salt to produce cryptographic keys resistant to brute-force attacks.
-
E.
Lucifer cipher
The Lucifer cipher is an early block cipher developed at IBM by Horst Feistel that served as a foundational design precursor to the Data Encryption Standard (DES).
- F. None of above. chosen
Statements (53)
| Predicate | Object |
|---|---|
| instanceOf |
C library function
ⓘ
Unix library function ⓘ authentication mechanism ⓘ password hashing function ⓘ |
| basedOn |
Data Encryption Standard
NERFINISHED
ⓘ
modified DES cipher ⓘ |
| category |
Unix security
ⓘ
cryptographic software ⓘ |
| definedIn |
crypt.h
ⓘ
unistd.h NERFINISHED ⓘ |
| extendedToSupport |
Blowfish-based password hashes
ⓘ
MD5-based password hashes ⓘ SHA-256-based password hashes ⓘ SHA-512-based password hashes ⓘ modular crypt format ⓘ |
| identifierPrefix |
$1$ for MD5-based hashes
ⓘ
$2$ or $2a$ or $2y$ for Blowfish-based hashes ⓘ $5$ for SHA-256-based hashes ⓘ $6$ for SHA-512-based hashes ⓘ |
| implementedIn |
BSD C libraries
NERFINISHED
ⓘ
glibc NERFINISHED ⓘ musl libc NERFINISHED ⓘ |
| implements | one-way hash function ⓘ |
| influenced | design of modern password hashing schemes ⓘ |
| input |
salt value
ⓘ
user password ⓘ |
| introducedIn | Unix Version 7 NERFINISHED ⓘ |
| introducedInYear | 1979 ⓘ |
| nameOrigin | crypt function in section 3 of Unix manual ⓘ |
| operatingSystemFamily | Unix NERFINISHED ⓘ |
| originalAlgorithm | DES-based password hash ⓘ |
| originalIterationCount | 25 DES iterations ⓘ |
| originalKeySpace | 56-bit DES key ⓘ |
| originalPasswordLengthLimit | 8 characters ⓘ |
| originalSaltEncoding | 2-character string ⓘ |
| originalSaltLength | 12 bits ⓘ |
| output | encoded password hash ⓘ |
| outputFormat | printable ASCII string ⓘ |
| parameter |
const char *key
ⓘ
const char *salt ⓘ |
| primaryUse |
password hashing
ⓘ
password verification ⓘ |
| returnType | char * ⓘ |
| standardizedIn |
POSIX
NERFINISHED
ⓘ
Single UNIX Specification NERFINISHED ⓘ |
| status | legacy for DES-based variant ⓘ |
| stillUsedFor | backward compatibility ⓘ |
| usedBy |
/etc/passwd
ⓘ
/etc/shadow ⓘ PAM authentication modules ⓘ login programs ⓘ |
| vulnerability |
limited password length in original DES variant
ⓘ
susceptible to brute-force attacks for DES-based hashes ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Subject: Unix crypt(3) Description of subject: Unix crypt(3) is a traditional Unix library function and algorithm used to hash and verify passwords, historically based on modified DES and later extended to support stronger schemes.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.