diff --git a/pgp-cert-d-java/src/main/java/pgp/cert_d/SharedPGPCertificateDirectoryImpl.java b/pgp-cert-d-java/src/main/java/pgp/cert_d/SharedPGPCertificateDirectoryImpl.java
index 096f1b5..c46d1f6 100644
--- a/pgp-cert-d-java/src/main/java/pgp/cert_d/SharedPGPCertificateDirectoryImpl.java
+++ b/pgp-cert-d-java/src/main/java/pgp/cert_d/SharedPGPCertificateDirectoryImpl.java
@@ -97,7 +97,7 @@ public class SharedPGPCertificateDirectoryImpl implements SharedPGPCertificateDi
 
     @Override
     public Certificate getBySpecialName(String specialName)
-            throws IOException, BadNameException {
+            throws IOException, BadNameException, BadDataException {
         File certFile = resolver.getCertFileBySpecialName(specialName);
         if (!certFile.exists()) {
             return null;
@@ -122,7 +122,7 @@ public class SharedPGPCertificateDirectoryImpl implements SharedPGPCertificateDi
 
     @Override
     public Certificate getBySpecialNameIfChanged(String specialName, String tag)
-            throws IOException, BadNameException {
+            throws IOException, BadNameException, BadDataException {
         Certificate certificate = getBySpecialName(specialName);
         if (certificate.getTag().equals(tag)) {
             return null;
diff --git a/pgp-certificate-store/src/main/java/pgp/certificate_store/CertificateReaderBackend.java b/pgp-certificate-store/src/main/java/pgp/certificate_store/CertificateReaderBackend.java
index c16b111..b3060f5 100644
--- a/pgp-certificate-store/src/main/java/pgp/certificate_store/CertificateReaderBackend.java
+++ b/pgp-certificate-store/src/main/java/pgp/certificate_store/CertificateReaderBackend.java
@@ -4,6 +4,8 @@
 
 package pgp.certificate_store;
 
+import pgp.certificate_store.exception.BadDataException;
+
 import java.io.IOException;
 import java.io.InputStream;
 
@@ -20,7 +22,8 @@ public interface CertificateReaderBackend {
      * @return certificate object
      *
      * @throws IOException in case of an IO error
+     * @throws BadDataException in case that the input stream does not contain OpenPGP certificate data
      */
-    Certificate readCertificate(InputStream inputStream) throws IOException;
+    Certificate readCertificate(InputStream inputStream) throws IOException, BadDataException;
 
 }