diff --git a/include/libgourou_common.h b/include/libgourou_common.h
index dbfedf6..6d4ed08 100644
--- a/include/libgourou_common.h
+++ b/include/libgourou_common.h
@@ -119,7 +119,8 @@ namespace gourou
 	DRM_FILE_ERROR,
 	DRM_FORMAT_NOT_SUPPORTED,
 	DRM_IN_OUT_EQUALS,
-	DRM_MISSING_PARAMETER
+	DRM_MISSING_PARAMETER,
+	DRM_INVALID_KEY_SIZE
     };
 
     /**
diff --git a/src/libgourou.cpp b/src/libgourou.cpp
index 22552dc..aa8ce32 100644
--- a/src/libgourou.cpp
+++ b/src/libgourou.cpp
@@ -927,8 +927,12 @@ namespace gourou
 
     void DRMProcessor::decryptADEPTKey(const std::string& encryptedKey, unsigned char* decryptedKey)
     {
+	if (encryptedKey.size() != 172)
+	    EXCEPTION(DRM_INVALID_KEY_SIZE, "Invalid encrypted key size (" << encryptedKey.size() << "). DRM version not supported");
+	    
 	ByteArray arrayEncryptedKey = ByteArray::fromBase64(encryptedKey);
 
+	
 	std::string privateKeyData = user->getPrivateLicenseKey();
 	ByteArray privateRSAKey = ByteArray::fromBase64(privateKeyData);