[EC-178] Fix RSA encrypt for newSymmetricKey, add null check (#17)

* Throw error if encKey is null

* Fix variable name

src/KeyConnector/Services/CryptoService.cs

@@ -108,7 +108,13 @@ namespace Bit.KeyConnector.Services
                 else
                 {
                     var newSymmetricKey = await _cryptoFunctionService.GetRandomBytesAsync(32);
-                    var decodedEncKey = await RsaEncryptAsync(_symmetricKey);
+                    var decodedEncKey = await RsaEncryptAsync(newSymmetricKey);
+
+                    if (decodedEncKey == null)
+                    {
+                        throw new Exception("RSA encryption failed. Your RSA key may not be configured properly.");
+                    }
+
                     encKey = Convert.ToBase64String(decodedEncKey);
                     await _applicationDataRepository.UpdateSymmetricKeyAsync(encKey);