Signing keys clarification needed

Trying to sign AppImage with my pgp keys:

```
Embedding MD5 digest
gpg2 and sha256sum are installed and user requested to sign, hence signing
Error: cannot embed key in AppImage: size exceeds reserved ELF section size
```

Could not find any information about what keys are permitted, obviously mine is too long (4096 bits). Any details on this somewhere?

The issue is in reference to linuxdeploy/linuxdeploy-plugin-appimage#9