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Hash Generator

Non-cryptographic hashes for checksums and hash tables. These are deliberately not cryptographic: they are fast and easy to find collisions for, so they must never be used for passwords or signatures.

Also called: checksum calculator, string hash.

Algorithm
Hash
92250123

92250123 using FNV-1a, 2451898659 in decimal. 6 characters hashed to 32 bits. This is not a cryptographic hash. Never use it for passwords, tokens or signatures.

In decimal
2451898659
Hash width
32
Input length
6
Algorithm
FNV-1a
On cryptographic use
This is not a cryptographic hash. Never use it for passwords, tokens or signatures.
On privacy
This runs in your browser. Nothing you paste is sent anywhere, which matters for anything sensitive.
How this is calculated
Method and background

How this is calculated

These algorithms exist for speed rather than security. FNV-1a and djb2 are hash table functions, designed to distribute keys evenly and be very fast, and CRC32 detects accidental corruption in transmission. All three are trivially reversible in the sense that collisions can be constructed deliberately, so none of them protects anything. Password hashing needs a deliberately slow algorithm with a salt, and integrity against a determined attacker needs a cryptographic hash.

FNV-1a mixes each byte by XOR then multiplies by a prime, which spreads changes across the whole output
p
The FNV prime

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

FNV-1a of a short string

Text
Numera
Algorithm
FNV-1a, non-cryptographic
Uppercase hex
No

Hash92250123

Structural: a 32 bit hash of a 6 character input

Open this example

the same input gives the same hash

Text
Numera
Algorithm
djb2, non-cryptographic
Uppercase hex
No

Hashaa00a3c5

boundary: determinism, the defining property

Open this example

Method and limits

What it assumes

  • UTF-8 byte encoding of the input.

What it deliberately does not model

  • None of these is cryptographically secure and none should be used for passwords, tokens or signatures.
  • CRC32 detects accidental corruption, not deliberate tampering.
  • Thirty-two bit outputs collide in practice after about 65,000 items by the birthday bound.

Formula version 1.0.0 · definition 1.0.0 · India · Report a problem with this calculator

Frequently asked questions

Can I use this to hash passwords?
No. Password hashing needs a deliberately slow algorithm with a per-password salt. A fast hash is exactly the wrong tool and makes brute forcing trivial.
What are these for then?
Hash tables, cache keys, sharding and detecting accidental corruption. All cases where speed matters and an adversary is not trying to construct a collision.