You can decide to generate your own crypto keys, usually with RSA size 2048 or 4096 and DH size 1024.
Please go to ISL Conference Proxy administration (http://localhost:7615/conf) and select Configuration - Advanced - Security. Use the option Generate new keys (high security) for all the sections and enter the desired key sizes. Do not forget to click Apply after modifying each section.
Warning: All users will need to download new ISL software executables to get new crypto keys. Affected files are ISL Light Desk.exe, ISL Light Client.exe, ISL Groop.exe and so on. If you generate new crypto keys and try running old executables (i.e. the ones that have old keys), they will fail to connect.