SPT-AKI-Installer/SPTInstaller/Helpers/FileHashHelper.cs

using System.Linq;
using System.Security.Cryptography;
using System.Text.RegularExpressions;
using Gitea.Model;

namespace SPTInstaller.Helpers;

public static class FileHashHelper
{
    public static string? GetGiteaReleaseHash(Release release)
    {
        var regex = Regex.Match(release.Body, @"Release Hash: (?<hash>\S+)");

        if (regex.Success)
        {
            return regex.Groups["hash"].Value;
        }

        return null;
    }

    public static bool CheckHash(FileInfo file, string expectedHash)
    {
        using var md5Service = MD5.Create();
        using var sourceStream = file.OpenRead();
        
        var sourceHash = md5Service.ComputeHash(sourceStream);
        var expectedHashBytes = Convert.FromBase64String(expectedHash);

        var matched = Enumerable.SequenceEqual(sourceHash, expectedHashBytes);

        return matched;
    }
}