Workaround for javaws jnpl error “Cannot grant permissions to unsigned jars.”

There’s an emergency and you’re trying to log on that ancient KVM/iLO/iDRAC and you’re getting an error like:

net.sourceforge.jnlp.LaunchException: Fatal: Application Error: Cannot grant permissions to unsigned jars.

Quick workaround:

Find the file. In my case it is located in /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/

Then find the row:

jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024

Comment it out, copy it, delete the MD5 string.

#jdk.jar.disabledAlgorithms=MD2, MD5, RSA keySize < 1024
jdk.jar.disabledAlgorithms=MD2, RSA keySize < 1024

Save the file. Try again. It should work.

Some more pointers if the problem persists: