Page 53 - Kaleidoscope Academic Conference Proceedings 2021

3.1.2 ITU-T Y.3801 - Functional requirements for ・ In the QKDN control layer, a QKDN controller function
quantum key distribution networks is to control QKDN resources to ensure secure, stable,
efficient, and robust operations of a QKDN.
There are the most common requirements for QKDNs in ・ In the QKDN management layer, a QKDN manager
terms of key rate, link length, key usage, and robustness, and function is to manage Fault, Configuration, Accounting,
so on [2]. In the context of QKDNs, ITU-T Y.3801 specifies Performance, and Security (FCAPS) aspects of a
the functional requirements for quantum layer, the key QKDN as a whole, and support user network
management layer, the QKDN control layer and the QKDN management.
management layer. Based on the layered structure of QKDN
shown in ITU-T Y.3800 and the functional requirements in ・ In the service layer, a cryptographic application
ITU-T Y.3801 [11], the detailed functional architecture is function consumes the shared key-pairs provided by a
developed in ITU-T Y.3802 [12]. QKDN and performs secure communications between
remote parties.
3.1.3 ITU-T Y.3802 - Quantum key distribution networks ・ In the user network management layer, a user network
– Functional architecture manager function performs FCAPS management
features of a user network.
ITU-T Y.3802 defines a functional architecture model of the
QKDN, as shown in Figure 3. It specifies detailed functional Based on the architecture, there are multiple possible
elements and reference points, architectural configurations network configurations of interconnecting various entities. It
and basic operational procedures of the QKDN. illustrates 1) a distributed QKDN; 2) a centralized QKDN; 3)
a centralized QKDN with hierarchical QKDN nodes; and 4)
The functional architecture model includes the following a centralized QKDN with a centralized key relay. In addition,
architectural components: 1) Layered structure (i.e. Figure 3); it describes basic operational procedures for service
2) With a cryptographic application, a user network manager, provisioning and system initialization, key generation, key
and an application link in the user network, basic functions request and supply, key relay, and key relay rerouting.
and links in the QKDN as follows:
・ QKD module: a set of hardware and software 3.1.4 ITU-T Y.3803 - Quantum key distribution networks
components that implement the cryptographic functions – Key management
and quantum optical processes, including QKD
protocols, synchronization, and distillation for key ITU-T Y.3803 [13] provides help for the design, deployment,
generation. It is contained within a defined and operation of key management of a QKDN to fulfill the
cryptographic boundary to demarcate one layer's requirements specified in ITU-T Y.3801.
responsibility on the keys.
・ Key Manager (KM): a functional module located in a
QKD node to perform the functions for key
management in the key management layer.
・ QKDN controller: a functional module, which is
located in the QKDN control layer to control a QKDN.
・ QKDN manager: A functional module, which is located
in the QKDN management layer to monitor and manage
a QKDN.
・ QKD link: a communication link between two QKD
modules to operate the QKD.
・ KM link: a communication link connecting KMs to
perform key management.
3) Functional elements: Subfunctions contained in each basic
function (e.g. a routing control function under the QKDN
controller); and 4) Detailed reference points. More
specifically: Figure 4 – Functional architecture model of
・ In the quantum layer, a pair of QKD modules connected the key management layer
by a QKD link generates quantum key distribution keys
(QKD-keys) by using QKD protocols. As shown Figure 4, the KM consists of a Key Management
・ In the key management layer, the KM function is to Agent (KMA), a Key Supply Agent (KSA), and a KM
control and management function. In addition, a KM link is
receive and manage keys generated by QKD modules
and QKD links, relay the keys, and supply the keys to divided into the KMA link (Kx-1) and the KSA link (Kx-2)
corresponding to their independent roles. ITU-T Y.3803
cryptographic applications.
presents basic key management operations in a QKDN. Each

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