Hash Generator
Compute the cryptographic hash of UTF-8 text using MD5, SHA-1, SHA-256, SHA-384, or SHA-512.
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NetTests can run this check on a schedule, preserve historical results, compare changes over time, and alert you the moment something breaks.
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What is a cryptographic hash?
A cryptographic hash function takes input of any length and produces a fixed-size digest. The same input always produces the same output, but a tiny change to the input produces a completely different digest (avalanche effect). Crucially, the process is one-way — you cannot reverse a hash to recover the original input.
Which algorithm should I use?
SHA-256 is the standard choice for most uses — it's secure, widely supported, and produces a 256-bit (64 hex character) digest. SHA-512 offers a larger output and is faster on 64-bit CPUs. Avoid MD5 and SHA-1 for security purposes — both have known collision vulnerabilities and are broken for cryptographic use.
Can I use this to hash passwords?
No. General-purpose hashes like SHA-256 are too fast — an attacker can compute billions of guesses per second on a GPU. For passwords, use a purpose-built slow hashing algorithm: bcrypt, Argon2, or scrypt. These are deliberately slow and memory-hard to resist brute force.
What is a hash collision and why does it matter?
A collision occurs when two different inputs produce the same hash digest. MD5 and SHA-1 are collision-broken — attackers can craft inputs that hash identically, enabling forged digital signatures and file tampering. SHA-256 and SHA-512 have no known practical collisions and remain secure.