What is a hash function?

A hash function is a one-way mathematical algorithm that converts input of any size into a fixed-length string of characters. The same input always produces the same hash, but you cannot reverse-engineer the original input from the hash.

Which hash algorithm should I use?

Use SHA-256 for general purposes — it is secure, fast, and widely supported. MD5 and SHA-1 are broken for security use (collision attacks found). For passwords, use bcrypt, scrypt, or Argon2 instead of raw hash functions.

Is MD5 still safe to use?

MD5 is not safe for security applications since collision attacks were demonstrated in 2004. However, MD5 is still useful for non-security checksums like file integrity verification and cache keys where collision resistance is not critical.

What is a hash collision?

A collision occurs when two different inputs produce the same hash output. For secure hash functions, collisions should be computationally infeasible. MD5 and SHA-1 have known collision vulnerabilities, making them unsafe for cryptographic use.

Hash Generator - MD5, SHA-1, SHA-256, SHA-512

Hvad er kryptografiske hashfunktioner?

En kryptografisk hashfunktion er en matematisk algoritme, der kortlægger data af vilkårlig størrelse til en streng af fast størrelse. Det er en envejsfunktion.

Understøttede Algoritmer

MD5 (128-bit): Hurtig, men betragtes som usikker. Bruges til checksums. Fast but considered insecure for cryptographic purposes. Still used for checksums.
SHA-1 (160-bit): Forældet algoritme. Anbefales ikke til sikkerhed, men bruges stadig i systemer som Git. Deprecated for security. Vulnerable to collision attacks since 2017.
SHA-256 (256-bit): Industristandard. Bruges i SSL/TLS og digitale signaturer. Part of SHA-2 family. Widely used in SSL, Bitcoin, and modern security.
SHA-512 (512-bit): Maksimal sikkerhed. Anbefales til hashing af adgangskoder. Strongest common hash. Used in high-security applications.

Ofte Stillede Spørgsmål

Er MD5 stadig sikker at bruge?

MD5 betragtes som kryptografisk knækket. Brug det kun til ikke-sikkerhedsmæssige formål. For sikkerhed skal du bruge SHA-256 eller SHA-512.

Kan et hash vendes om (dekrypteres)?

Nej. Hashfunktioner er envejs. Svage hashes kan dog gættes via rainbow tables. Brug 'salt' til adgangskoder.

🔐 Hash Generator

Hvad er kryptografiske hashfunktioner?

Understøttede Algoritmer

Ofte Stillede Spørgsmål

Key Facts

Frequently Asked Questions

🔐 Hash Generator

Hvad er kryptografiske hashfunktioner?

Understøttede Algoritmer

Ofte Stillede Spørgsmål

Key Facts

Frequently Asked Questions

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