Hash a UTF-8 value with SHA-256.

C#: Use SHA256.HashData for a one-shot content digest.

using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.Json;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Globalization;
using System.Security.Cryptography;
using System.Threading;
using System.Threading.Tasks;

Console.WriteLine(Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes("hello"))).ToLowerInvariant());

Expected output EXAMPLE

2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824

Details

Use Program.cs in a .NET 8 console project and run dotnet run. Uses only the .NET standard libraries. Use SHA256.HashData for a one-shot content digest.

Keep in mind

A plain hash does not authenticate a sender and should not be used by itself to store passwords.

✓ Verified

Tested on Ubuntu 24.04.5 LTS · 2026-11-02 18:07:07 UTC · 8.0.425 · libc6 2.39-0ubuntu8.9

Test inputs, results and environment

The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.

Architecture / host kernel: x86_64 / 6.18.54.1-microsoft-standard-WSL2
Snippet identity / locale: uid=65534, gid=65534 (unprivileged) / C.UTF-8
Interpreter invocation: dotnet build --no-restore && dotnet out/csharp.dll
Container image ID: sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd
Code SHA-256: 19a9768ef20509b6e3ba552ad200f4e949105fb8ee3d6db35baf0641e630b27a
Dependencies: libc6 2.39-0ubuntu8.9

Test input setup

These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.

# No input files required.

Observed standard output

2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824

Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.