[knx] support for KNX secure

[holgerfriedrich]

1. [open] Support for KNX data secure packets shall be added to OpenHAB.
   Reading and writing authenticated KNX packets should be possible.
2. [done] Support for KNX IP secure shall be added to OpenHAB.
   Using an encrypted connection to a IP secure interface or an IP secure router shall be possible.

Calimero library seems to have all the necessary prerequisites at hand in latest version (2.5M1).
The process includes exporting an encrypted keyring from ETS software, decrypt it using the Calimero library functions in the OH knx binding, and use the corresponding group address keys from the keyring file.

Prerequesites

• Calimero -> Java 11
• Calimero -> Calimero version >=2.5M1

Suggested Approach

• switch to Calimero 2.5 ([knx] update to most recent calimero version #6849)
• add configuration items for keyring file and password ([knx] Allow decoding of KNX Data Secure frames #12434)
• data secure: reading of keyring, and use decryption for packets with matching group addresses from the keyring (listening only) ([knx] Allow decoding of KNX Data Secure frames #12434)
• data secure: allow write access
• data secure: allow triggered read
• IP secure: support secure tunneling ([knx] Add support for KNX IP Secure #12709)
• IP secure: support secure routing (implemented, untested) ([knx] Add support for KNX IP Secure #12709)

[holgerfriedrich]

I have already been playing around with this and willing to implement. If anyone is already working on this topic or wants to give some advice, it would be appreciated.

[J-N-K]

If there is no immediate need (i.e. bugs or security issues), we usually don't use snapshots of dependencies. Do you happen to know when Calimero 2.5 will be released? And thanks for the offer to implement that.

[holgerfriedrich]

@J-N-K thanks for letting me know. My PR is still WIP and far from finished. Decrypting secure PDUs using the exported keyring from ETS works fine with the Calimero snapshot.
The more complicated thing is to setup a secure device needed for transmitting secure messages from openhab to other devices on the bus. I was not able to get this implemented properly yet.
Once it is running, I will contact the author.

[J-N-K]

If you need help regarding the openHAB side, please ping me.