Miscelanious trials

IdentityShroud.Core/Security/JwtSignatureGenerator.cs

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+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.AspNetCore.WebUtilities;
+
+namespace IdentityShroud.Core;
+
+public class JwtSignatureGenerator
+{
+    /// <summary>
+    /// Generates a JWT signature using RS256 algorithm
+    /// </summary>
+    /// <param name="headerBase64Url">Base64Url encoded header</param>
+    /// <param name="payloadBase64Url">Base64Url encoded payload</param>
+    /// <param name="privateKey">RSA private key (PEM format or RSA parameters)</param>
+    /// <returns>Base64Url encoded signature</returns>
+    public static string GenerateRS256Signature(string headerBase64Url, string payloadBase64Url, RSA privateKey)
+    {
+        // Combine header and payload with a period
+        string dataToSign = $"{headerBase64Url}.{payloadBase64Url}";
+
+        // Convert to bytes
+        byte[] dataBytes = Encoding.UTF8.GetBytes(dataToSign);
+
+        // Sign the data using RSA-SHA256
+        byte[] signatureBytes = privateKey.SignData(dataBytes, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
+
+        // Convert signature to Base64Url encoding
+        string signature = WebEncoders.Base64UrlEncode(signatureBytes);
+
+        return signature;
+    }
+    
+    public static string GenerateCompleteJwt(string headerBase64Url, string payloadBase64Url, RSA privateKey)
+    {
+        string signature = GenerateRS256Signature(headerBase64Url, payloadBase64Url, privateKey);
+        return $"{headerBase64Url}.{payloadBase64Url}.{signature}";
+    }    
+}