diff --git a/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java
index 128cefe..77073bc 100755
--- a/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java
@@ -74,11 +74,15 @@ public class OAuthAuthorizationCodeAuthorizationFilter extends OAuthAuthorizatio
 	
 	@Override
 	protected Form createForm() {
-		Form form = new Form().param("grant_type", "authorization_code")
-				.param("code", this.code);
+		Form form = new Form().param("grant_type", "authorization_code");
 		if (this.redirectUri != null)
 			form.param("redirect_uri", this.redirectUri.toString());
 		return form;
 	}
+	
+	@Override
+	protected void extendFormSensitive(Form form) {
+	    form.param("code", this.code);
+	}
 
 }
diff --git a/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java
index e8d175a..389d263 100755
--- a/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java
@@ -27,6 +27,9 @@ import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.Response.Status.Family;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;
 
 /**
@@ -36,6 +39,8 @@ import com.fasterxml.jackson.jaxrs.json.JacksonJaxbJsonProvider;
  */
 public abstract class OAuthAuthorizationFilter implements AuthorizationFilter {
 	
+    private final Logger logger = LoggerFactory.getLogger(this.getClass());
+    
 	private final String tokenUrl;
 	private final String clientId;
 	private final String clientSecret;
@@ -114,11 +119,20 @@ public abstract class OAuthAuthorizationFilter implements AuthorizationFilter {
 		}
 
 		form.param("client_id", this.clientId);
-		if (this.clientSecret != null)
-			form.param("client_secret", this.clientSecret);
 		if (this.scope != null)
 			form.param("scope", this.scope);
 		
+		this.logger.trace("Sending OAuth request: {}", form);
+		
+		if (this.refreshToken != null) {
+		    this.extendRefreshFormSensitive(form);
+		} else {
+            this.extendFormSensitive(form);
+		}
+
+        if (this.clientSecret != null)
+            form.param("client_secret", this.clientSecret);
+		
 		Entity<Form> entity = Entity.form(form);
 		
 		Client client = ClientBuilder.newBuilder()
@@ -127,9 +141,13 @@ public abstract class OAuthAuthorizationFilter implements AuthorizationFilter {
 		WebTarget target = client.target(this.tokenUrl);
 
 		Response response = target.request().post(entity);
+		
+        this.logger.debug("Received OAuth response: {}", response.getStatus());
 
         @SuppressWarnings("unchecked")
         Map<String, Object> responseMap = response.readEntity(Map.class);
+
+        this.logger.trace("Received OAuth response: {}", responseMap);
 		
 		if (response.getStatusInfo().getFamily() != Family.SUCCESSFUL) {
             String code = (String) responseMap.get("error");
@@ -152,5 +170,10 @@ public abstract class OAuthAuthorizationFilter implements AuthorizationFilter {
 	}
 	
 	protected abstract Form createForm();
+	
+	protected void extendRefreshFormSensitive(Form form) {
+	}
+
+    protected abstract void extendFormSensitive(Form form);
 
 }
diff --git a/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java
index 79e63da..40856e8 100755
--- a/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java
@@ -37,5 +37,9 @@ public class OAuthClientCredentialAuthorizationFilter extends OAuthAuthorization
 	protected Form createForm() {
 		return new Form().param("grant_type", "client_credentials");
 	}
+	
+	@Override
+	protected void extendFormSensitive(Form form) {
+	}
 
 }
diff --git a/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java
index 2037127..39a1a2e 100755
--- a/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java
@@ -53,8 +53,12 @@ public class OAuthPasswordGrantAuthorizationFilter extends OAuthAuthorizationFil
 	@Override
 	protected Form createForm() {
 		return new Form().param("grant_type", "password")
-				.param("username", this.username)
-				.param("password", this.password);
+				.param("username", this.username);
+	}
+	
+	@Override
+	protected void extendFormSensitive(Form form) {
+	    form.param("password", this.password);
 	}
 
 }