diff --git a/test/utest.cpp b/test/utest.cpp
index 9e55f2a..cdf9b99 100644
--- a/test/utest.cpp
+++ b/test/utest.cpp
@@ -237,7 +237,7 @@
         command("echo \"image-u-boot file \" > " + ubootFile);
 
         std::string pkeyFile = extractPath.string() + "/" + "private.pem";
-        command("openssl genrsa  -out " + pkeyFile + " 2048");
+        command("openssl genrsa  -out " + pkeyFile + " 4096");
 
         std::string pubkeyFile = extractPath.string() + "/" + "publickey";
         command("openssl rsa -in " + pkeyFile + " -outform PEM " +