Signing key has not been configured.
https://dev.openwrt.org/changeset/38284 Add package signing key and certificate configuration options to the "Image configuration" submenu. If enabled, the Packages.gz list will be signed as file Packages.sig. The passphrase for the signing key can be sourced from a file or entered by the user. The signing certificate is automatically added to the firmware image if opkg-smime is selected.
是因为增加包签名，可以查看下面链接中，对增加这一功能的描述
https://dev.openwrt.org/changeset/38284
上面有这样说Add package signing key and certificate configuration options to the
"Image configuration" submenu.
当执行make menuconfig 选择image configuration ——————必须选择，按Y键，回车，就能
看见关于密匙的配置了
回车后 选择package signing options
然后输入签名文件和证书，签名和证书可以通过openssl来制作
具体制作可以参考http://killeraction.iteye.com/blog/858325
完全可以参考上面的文章制作一个
