What to do when experiencing The following signatures were invalid: BADSIG.
DOWNLOAD UBUNTU 16.04 64 BIT INSTALL
Replace virtualbox-6.1 by virtualbox-6.0 or virtualbox-5.2 to install the latest VirtualBox 6.0 or 5.2 build. The old Sun public key for apt-secure can be downloaded here.) (As of VirtualBox 3.2, the signing key was changed.
DOWNLOAD UBUNTU 16.04 64 BIT ARCHIVE
Oracle Corporation (VirtualBox archive signing key) The key fingerprint for oracle_vbox_2016.asc isī9F8 D658 297A F3EF C18D 5CDF A2F6 83C5 2980 AECF
The SHA256 checksums should be favored as the MD5 algorithm must be treated as insecure! You might want to compare the checksums to verify the integrity of downloaded packages.