diff --git a/src/main/java/cz/trask/adfs/service/AdfsTokenService.java b/src/main/java/cz/trask/adfs/service/AdfsTokenService.java
index 9255883..d1e083a 100644
--- a/src/main/java/cz/trask/adfs/service/AdfsTokenService.java
+++ b/src/main/java/cz/trask/adfs/service/AdfsTokenService.java
@@ -28,6 +28,7 @@ import java.util.UUID;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 import cz.trask.adfs.config.AdfsConfig;
@@ -169,16 +170,10 @@ public class AdfsTokenService {
     }
 
     private String generateJwtAssertion(String clientId) throws Exception {
-        String certPem = new String(Base64.getDecoder().decode(config.getCertificate().replaceAll("\\s+", "")), StandardCharsets.UTF_8)
-                .replace("-----BEGIN CERTIFICATE-----", "")
-                .replace("-----END CERTIFICATE-----", "")
-                .replaceAll("\\s+", "");
+        String certPem = new String(Base64.getDecoder().decode(config.getCertificate().replaceAll("\\s+", "")), StandardCharsets.UTF_8);
         X509Certificate cert = getCertificate(certPem);
-        
-        String keyPem = new String(Base64.getDecoder().decode(config.getPrivateKey().replaceAll("\\s+", "")), StandardCharsets.UTF_8)
-                .replace("-----BEGIN PRIVATE KEY-----", "")
-                .replace("-----END PRIVATE KEY-----", "")
-                .replaceAll("\\s+", "");
+
+        String keyPem = new String(Base64.getDecoder().decode(config.getPrivateKey().replaceAll("\\s+", "")), StandardCharsets.UTF_8);
         PrivateKey privateKey = getPrivateKey(keyPem);
 
         MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
@@ -221,7 +216,7 @@ public class AdfsTokenService {
         }
 
         byte[] decodedBytes = Base64.getUrlDecoder().decode(parts[1]);
-        Map<String, Object> claims = objectMapper.readValue(decodedBytes, Map.class);
+        Map<String, Object> claims = objectMapper.readValue(decodedBytes, new TypeReference<Map<String, Object>>() {});
         Number exp = (Number) claims.get("exp");
         if (exp == null) {
             throw new IllegalArgumentException("JWT does not contain 'exp' claim");