sha1 vs xxhash3

results.txt

BenchmarkDotNet v0.15.4, Linux Ubuntu 25.04 (Plucky Puffin)
Intel Core Ultra 7 155U 0.40GHz, 1 CPU, 14 logical and 12 physical cores
.NET SDK 9.0.110
  [Host]     : .NET 9.0.9 (9.0.9, 9.0.925.41916), X64 RyuJIT x86-64-v3
  DefaultJob : .NET 9.0.9 (9.0.9, 9.0.925.41916), X64 RyuJIT x86-64-v3


| Method  | Length   | Mean             | Error          | StdDev           | Ratio | RatioSD | Allocated | Alloc Ratio |
|-------- |--------- |-----------------:|---------------:|-----------------:|------:|--------:|----------:|------------:|
| SHA1    | 1024     |      1,038.23 ns |      20.541 ns |        19.214 ns |  1.00 |    0.03 |         - |          NA |
| XxHash3 | 1024     |         46.19 ns |       0.953 ns |         1.272 ns |  0.04 |    0.00 |         - |          NA |
|         |          |                  |                |                  |       |         |           |             |
| SHA1    | 1048576  |    528,949.80 ns |  10,499.304 ns |    19,720.239 ns |  1.00 |    0.05 |         - |          NA |
| XxHash3 | 1048576  |     40,954.72 ns |     812.074 ns |     1,027.014 ns |  0.08 |    0.00 |         - |          NA |
|         |          |                  |                |                  |       |         |           |             |
| SHA1    | 67108864 | 34,684,811.74 ns | 685,524.563 ns | 1,769,557.932 ns |  1.00 |    0.07 |         - |          NA |
| XxHash3 | 67108864 |  4,133,490.54 ns |  71,945.439 ns |    56,170.266 ns |  0.12 |    0.01 |         - |          NA |

test.cs

using System.IO.Hashing;
using System.Security.Cryptography;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

#if DEBUG // just to show working
var obj = new HashBench { Length = 1024 * 1024 };
obj.Setup();
Console.WriteLine(obj.ComputeSha1());
Console.WriteLine(obj.ComputeXxHash3());
#else
BenchmarkRunner.Run<HashBench>();
#endif

[MemoryDiagnoser]
public class HashBench
{
    private byte[] _data = [];
    private readonly SHA1 _sha1 = SHA1.Create();

    [GlobalSetup]
    public void Setup()
    {
        _data = new byte[Length];
        Random.Shared.NextBytes(_data);
    }

    [Params(1024, 1024 * 1024, 64 * 1024 *1024)] public int Length { get; set; }

    private static void ThrowNotSupported() => throw new NotSupportedException();

    [Benchmark(Description = nameof(SHA1), Baseline = true)]
    public int ComputeSha1()
    {
        Span<byte> target = stackalloc byte[_sha1.HashSize / sizeof(byte)];
        if (!_sha1.TryComputeHash(_data, target, out int bytes)) ThrowNotSupported();
        return bytes;
    }

    [Benchmark(Description = nameof(XxHash3))]
    public int ComputeXxHash3()
    {
        _ = XxHash3.HashToUInt64(_data);
        return sizeof(ulong);
    }
}