When updating rvm getting error message like the following.
GPG signature verification failed for '/usr/local/rvm/archives/rvm-1.26.5.tgz' - 'https://github.com/wayneeseguin/rvm/releases/download/1.26.5/1.26.5.tar.gz.asc'!
try downloading the signatures:

sudo gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
or if it fails:
command curl -sSL https://rvm.io/mpapis.asc | sudo gpg --import -
the key can be compared with:

Type the following in terminal to fix it.
sudo gpg --keyserver hkp://keys.gnupg.net --recv-keys D39DC0E3