Quicksilver

Currently UDP encryptiuon is not supported by clients so the only way to get a secure ADCS hub is to enforce searches to be passive.
This is a proposal to help with this unneeded strain to the hub. While Asymetric encryption may be optimal in sense of security.
A symmetric cipher will protect perfectly against outside adversaries given the hub-client connections is also running ADCS and Tokens containing sufficient entropie .

To signal Support for this ADC0 enhancements clients should add "ADC1" in their SU field (additional to ADC0).

If a client signals support for ADC1, UDP messages to the client may be encrypted using AES/ECB/PKCS5Padding as Cypher/Blockmode/Padding.
As key for the AES cipher the first 16 bytes of the Tiger hash of the token sent with the search are used.
Tiger is choosen as this must work hubindependent and Tiger support is currently mandatory in any client.