# C# webhook signing

```csharp
using System.Security.Cryptography;
using System.Text;

static string Sign(byte[] rawBody, string secret)
{
    using var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(secret));
    return Convert.ToHexString(hmac.ComputeHash(rawBody)).ToLowerInvariant();
}
```

Sign the exact UTF-8 bytes sent and set `X-Platform-Signature`. Test vector: secret `test-secret`, body `{"status":"delivered"}`, signature `bfebae765b7f20464b4b64d37314fc073a178a293762aaf32920be724d5fde18`.