Table of Contents

MurmurHash3_128 Class

Definition

Namespace
Bodu.IO.Hashing
Assembly
Bodu.IO.Hashing.dll
Package
Bodu.IO.Hashing 1.0.0
Source
MurmurHash3.128.cs

Computes a 128-bit (16-byte) non-cryptographic hash using the MurmurHash3_x64_128 variant by Austin Appleby, optimized for 64-bit platforms. This class cannot be inherited.

public sealed class MurmurHash3_128 : MurmurHash3, IDisposable
Inheritance
MurmurHash3_128
Implements
Inherited Members
Extension Methods

Remarks

MurmurHash3_128 maintains two independent 64-bit accumulators (h1 and h2) seeded from the constructor-supplied value. Input is consumed in 16-byte blocks; each block word is mixed through multiply-rotate-multiply passes before being folded into the appropriate accumulator. Remaining 1-15 bytes are handled by a tail switch. Both accumulators are cross-mixed and finalized via FMix64(ulong) to produce the 128-bit output.

A 32-bit seed may be supplied at construction time. Both accumulators are initialized to the same seed value, matching the behavior of the reference MurmurHash3_x64_128 implementation.

Parameters at a glance.

  • Output size: 128 bits (16 bytes), little-endian.
  • Variant: MurmurHash3_x64_128 - optimized for 64-bit platforms.
  • Block size: 16 bytes; tail pass for remaining 1-15 bytes.
  • Seed: 32 bits, applied to both accumulators; defaults to 0.

When to choose MurmurHash3_128. Pick this when collision pressure makes 32 or 64 bits inadequate - content fingerprinting, deduplication keys, large bloom filters. Output is also useful as a pair of 64-bit halves for two-hash cuckoo or split-key schemes. CityHash128 is a comparable alternative with similar quality and slightly better throughput on long inputs on modern 64-bit CPUs.

important

This algorithm is not cryptographically secure and must not be used for password hashing, digital signatures, or any application requiring adversarial collision resistance. 

using Bodu.IO.Hashing;
using Bodu.IO.Hashing.Extensions;

// 128-bit fingerprint of a content blob.
var m = new MurmurHash3_128();
byte[] fingerprint = m.ComputeHash(blob);

// Custom seed to isolate a second hash family for cuckoo / bloom-filter use.
var m2 = new MurmurHash3_128(seed: 0xC2B2AE35u);

Constructors

MurmurHash3_128()

Initializes a new instance of the MurmurHash3_128 class with a seed of zero.

public MurmurHash3_128()

MurmurHash3_128(uint)

Initializes a new instance of the MurmurHash3_128 class with the specified seed.

public MurmurHash3_128(uint seed)

Parameters

seed uint

The 32-bit seed value used to initialize both 64-bit accumulators.

Methods

Dispose(bool)

Releases the resources used by the current instance, optionally clearing managed state.

protected override void Dispose(bool disposing)

Parameters

disposing bool

true when called from Dispose(); false when called from a finalizer. Managed resources are released only when disposing is true.

Remarks

Override in a derived class to release additional resources owned by the subclass. Always invoke base.Dispose(disposing) from the override so that the buffered state is cleared.

Applies to

ProductVersions
.NET8, 10

See Also

MurmurHash3
MurmurHash3_32