A fast(ish) SHA-2 (256) implementation in C#.
This implementation is entirely in managed code and only has a chance at being more performance than System.Security.Cryptography for very small data to offset the overhead of its native calls.
Built as a challenge to myself after unearthing my original SHA256 implementation I wrote for a challenge when I was an apprentice many years ago.
More details of what and why can be found on my blog posts:
BenchmarkDotNet v0.13.12, Windows 11 (10.0.22621.1778/22H2/2022Update/SunValley2)
Intel Core i7-8700K CPU 3.70GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET SDK 8.0.201
[Host] : .NET 8.0.2 (8.0.224.6711), X64 RyuJIT AVX2
DefaultJob : .NET 8.0.2 (8.0.224.6711), X64 RyuJIT AVX2
| Method | Mean | Error | StdDev | Ratio | Gen0 | Allocated | Alloc Ratio |
|---|---|---|---|---|---|---|---|
| SystemSecurityCryptography | 405.9 ns | 5.42 ns | 4.23 ns | 1.00 | 0.0176 | 112 B | 1.00 |
| JcFastSha256 | 387.2 ns | 3.28 ns | 2.91 ns | 0.95 | 0.0086 | 56 B | 0.50 |
| JcFastSha256Span | 381.9 ns | 4.46 ns | 3.95 ns | 0.94 | - | - | 0.00 |
| JcFastSha256Native | 228.6 ns | 3.28 ns | 3.06 ns | 0.56 | 0.0138 | 88 B | 0.79 |