Liaison statement
LS on work progress on Quantum Key Distribution (QKD) network in SG11 (as of October 2023)

ITU-T SG11 is pleased to inform you about SG11 progress on Quantum Key
Distribution (QKD) studies. During SG11 meeting (Geneva, 10 – 20 October 2023),
Q2/11 has made progress of the following work items:

1. The items consented at the SG11 meeting
The following five Recommendations were consented at the SG11 meeting.

1.1. Recommendation ITU-T Q.4160 (ex. Q.QKDN-profr): Quantum key distribution
networks – Protocol framework in SG11-TD716/GEN Recommendation ITU-T Q.4160
specifies a framework for signalling and protocols for quantum key distribution
network (QKDN).

1.2. Recommendation ITU-T Q.4161 (ex. Q.QKDN_Ak): Protocols for Ak interface
for quantum key distribution network in SG11-TD717/GEN

Recommendation ITU-T Q.4161 specifies protocols for Ak interface in quantum key
distribution networks (QKDN). Ak is a reference point connecting a
cryptographic application and a key supply function in a KSA. It is responsible
for sending key requests from the cryptographic application to the KSA,
performing authentication between the cryptographic application and the KSA,
and supplying keys from the KSA to the cryptographic application.

1.3. Recommendation ITU-T Q.4162 (ex. Q.QKDN_Kq-1): Protocols for Kq-1
interface for quantum key distribution network in SG11-TD718/GEN

Recommendation ITU-T Q.4162 specifies protocols for Kq-1 interface in quantum
key distribution networks (QKDN). Kq-1 is a reference point connecting a key
storage function in a KMA with a QKD-key supply function in a QKD module. It is
responsible for transferring QKD-keys generated by a QKD module to the KM.

1.4. Recommendation ITU-T Q.4163 (ex. Q.QKDN_Kx): Protocols for Kx interface
for quantum key distribution network in SG11-TD719/GEN

Recommendation ITU-T Q.4163 specifies protocols for Kx interface in quantum key
distribution networks (QKDN). Kx is a reference point connecting two KMs in
each QKD node via a KM link. It is responsible for exchanging information and
operations required for key relay, key synchronization and authentication
between KMs.

1.5. Recommendation ITU-T Q.4164 (ex. Q.QKDN_Ck): Protocols for Ck interface
for quantum key distribution network in SG11-TD712/GEN

Recommendation ITU-T Q.4164 specifies protocols for Ck interface in quantum key
distribution networks (QKDN). Ck is a reference point connecting the QKDN
controller control and management function in a QKDN controller and a KM
control and management function in a KM. It is responsible for the QKDN
controller to communicate control information with a KMA and a KSA.

2. Revised on-going work items
The following two draft Recommendations were advanced at the Q2/11 meeting:

2.1. Draft Recommendation ITU-T Q.QKDNi-profr: Quantum key distribution
networks interworking– Protocol framework in SG11-TD715/GEN

Recommendation ITU-T Q.QKDNi_profr specifies protocol framework including
signalling requirements and protocols for quantum key distribution networks
interworking (QKDNi).

2.2. Draft Recommendation ITU-T Q.QKDN_Mk: Protocols for interfaces on quantum
key distribution network manager in SG11-TD713-R1/GEN

Recommendation ITU-T Q.QKDN_Mk specifies protocols for interfaces on a quantum
key distribution network manager (QKDN manager) in quantum key distribution
networks (QKDN). Reference points on a QKDN manager are defined in [ITU-T
Y.3802] which are Mq, Mqrp, Mops, Mk, Mc, Mu and Mx. A QKDN manager performs
FCAPS functions through these interfaces to QKD modules, KMs, QKDN controllers,
QKD links, user network managers and corresponding QKDN managers.

3. New work items started at the SG11 meeting in October 2023
The following new WI was started at the SG11 meeting:

3.1. Draft Recommendation ITU-T Q.QKDNi_KM: Protocols for interfaces between
key managers for quantum key distribution network interworking in SG11-TD714/GEN

Recommendation ITU-T Q.QKDNi_KM specifies protocols for Kxi and Kxi’ interfaces
in quantum key distribution networks interworking (QKDNi).

4.Conclusion

SG11 continues studying the signalling requirements and protocols of QKDN.
Q2/11 looks forward to close collaboration with ITU-T SG2, SG13, SG15, SG17,
ETSI ISG-QKD, ISO/IEC JTC1/SC27, AG4, IETF/IRTF, and relevant groups for future
standardization on QKD networks.

Attachments:
1) Recommendation ITU-T Q.4160 (ex. Q.QKDN-profr): Quantum key distribution
networks – Protocol framework in SG11-TD716/GEN 2) Recommendation ITU-T Q.4161
(ex. Q.QKDN_Ak): Protocols for Ak interface for quantum key distribution
network in SG11-TD717/GEN 3) Recommendation ITU-T Q.4162 (ex. Q.QKDN_Kq-1):
Protocols for Kq-1 interface for quantum key distribution network in
SG11-TD718/GEN 4) Recommendation ITU-T Q.4163 (ex. Q.QKDN_Kx): Protocols for Kx
interface for quantum key distribution network in SG11-TD719/GEN 5)
Recommendation ITU-T Q.4164 (ex. Q.QKDN_Ck): Protocols for Ck interface for
quantum key distribution network in SG11-TD712/GEN 6) Draft Recommendation
ITU-T Q.QKDNi-profr: Quantum key distribution networks interworking– Protocol
framework in SG11-TD715/GEN 7) Draft Recommendation ITU-T Q.QKDN_Mk: Protocols
for interfaces on quantum key distribution network manager in SG11-TD713-R1/GEN
8) Draft Recommendation ITU-T Q.QKDNi_KM: Protocols for interfaces between key
managers for quantum key distribution network interworking in SG11-TD714/GEN