### Exemplo C# de implementação de geração de assinatura (.NET 5.0 e posterior): 
<div class="note">
<p><strong>Observação</strong></p>
<p>Para usar o método <code>Convert.ToHexString</code>, você precisa do .NET 5.0 e posterior.<p></p>Se você tiver o .NET 7.0 e posterior, também poderá usar o método <code>CryptographicOperations.FixedTimeEquals</code> em vez de <code>ConstantTimeEquals</code>.</p>
</div>

```csharp
// For .NET 5.0 and later, you can use the more concise Convert.ToHexString method:
using System;
using System.Security.Cryptography;
using System.Text;
public static class XsollaWebhookSignature
{
    public static string ComputeSha1(string jsonBody, string secretKey)
    {
        string dataToSign = jsonBody + secretKey;
        using var sha1 = SHA1.Create();
        byte[] hashBytes = sha1.ComputeHash(Encoding.UTF8.GetBytes(dataToSign));
        return Convert.ToHexString(hashBytes).ToLower();
    }
    public static bool VerifySignature(string jsonBody, string secretKey, string receivedSignature)
    {
        string computedSignature = ComputeSha1(jsonBody, secretKey);
        string receivedSignatureLower = receivedSignature.ToLower();
        // Use constant-time comparison to prevent timing attacks
        return ConstantTimeEquals(computedSignature, receivedSignatureLower);
    }
    private static bool ConstantTimeEquals(string a, string b)
    {
        if (a.Length != b.Length)
        {
            return false;
        }
        int result = 0;
        for (int i = 0; i < a.Length; i++)
        {
            result |= a[i] ^ b[i];
        }
        return result == 0;
    }
}
```