C# で SHA256 のハッシュ文字列を得る

GetSHA256HashedString_net5.cs

// .NET 5 まで
using System.Linq;
using System.Security.Cryptography;
using System.Text;

public static class StringExtensions
{
    static readonly SHA256CryptoServiceProvider hashProvider = new SHA256CryptoServiceProvider();
    public static string GetSHA256HashedString(this string value)
        => string.Join("", hashProvider.ComputeHash(Encoding.UTF8.GetBytes(value)).Select(x => $"{x:x2}"));
}

GetSHA256HashedString_net6.cs

// .NET 6 以降
using System.Linq;
using System.Security.Cryptography;
using System.Text;

public static class StringExtensions
{
    static readonly HashAlgorithm hashAlgorithm = SHA256.Create();
    public static string GetSHA256HashedString(this string value)
        => string.Join("", hashAlgorithm.ComputeHash(Encoding.UTF8.GetBytes(value)).Select(x => $"{x:x2}"));
}