| QIRG | C. Wang |
| Internet-Draft | A. Rahman |
| Intended status: Informational | InterDigital Communications, LLC |
| Expires: August 7, 2020 | R. Li |
| NICT | |
| February 4, 2020 |
Applications and Use Cases for the Quantum Internet
draft-wang-qirg-quantum-internet-use-cases-02
The Quantum Internet has the potential to improve Internet protocol and application functionality by incorporating quantum information technology into the infrastructure of the overall Internet. In this document, we provide an overview of some applications expected to be used on the Quantum Internet, and then categorize them using the standard telecommunications classification of control plane versus data plane functionality. Other classification schemes are also possible and discussed briefly. We then provide detailed use cases for selected applications. The intent of this document is to provide a common understanding and framework of applications and use cases for the Quantum Internet.
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The classical Internet has been constantly growing since it first became commercially popular in the early 1990's. It essentially consists of a large number of end-nodes (e.g., laptops, smart phones, network servers) connected by routers. The end-nodes run applications that provide some value added service for the end-users such as processing and transmission of voice, video or data. The physical connections between the various nodes in the Internet include Digital Subscriber Lines (DSLs), fiber optics, etc. Bits are transmitted across the classical Internet in packets.
Research and experimentation have picked up over the last few years for developing a Quantum Internet [Wehner]. It is anticipated that the Quantum Internet will provide intrinsic benefits such as improved computing power and better end-user and network security. The Quantum Internet will have end-nodes, which may be connected by quantum repeaters/routers. These quantum end-nodes will also run value-added applications which will be discussed later. The physical connections between the various nodes in the Quantum Internet are expected to be primarily fiber optics and free-space optics. Unlike the classical Internet, qubits (and not classical bits or packets) are expected to be transmitted across the Quantum Internet due to the underlying physics. In general, compared to the classical Internet, the Quantum Internet will operate according to fundamentally different physical principles such as quantum superposition, entanglement and teleportation [I-D.irtf-qirg-principles].
The Quantum Internet is not anticipated to replace the classical Internet. Instead the Quantum Internet will be integrated into the classical Internet to form a new hybrid Internet. The process of integrating the Quantum Internet with the classical Internet is similar to, but with more profound implications, as the process of introducing any new communication and networking paradigm into the existing Internet. The intent of this document is to provide a common understanding and framework of applications and use cases for the Quantum Internet.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
This document assumes that the reader is familiar with the quantum information technology related terms and concepts that are described in [I-D.irtf-qirg-principles]. In addition, the following terms and acronyms are defined here for clarity:
The Quantum Internet is expected to be extremely beneficial for a subset of existing and new applications. We use "applications" in the widest sense of the word and include functionality typically contained in Layers 4 (Transport) to Layers 7 (Application) of the Open System Interconnect (OSI) model.
The expected applications using Quantum Internet are still being developed as we are in the formative stages of the Quantum Internet [Castelvecchi] [Wehner]. However, an initial (and non-exhaustive) list of the applications to be supported on the Quantum Internet can be identified and classified using different schemes. We concentrate on the telecom centric classification of control plane versus data plane. We also briefly discuss other possible classification schemes.
Traditionally, in the Internet most applications are classified as either control plane functionality or data plane functionality. Similarly, we classify Quantum Internet applications using the paradigm of control plane applications versus data plane applications where:
Some examples of classic Internet control plane applications are Domain Name Server (DNS), Session Information Protocol (SIP), and Internet Control Message Protocol (ICMP). Furthermore, examples of classic Internet data plane applications are E-mail, web browsing, and video streaming.
Control Plane Applications using Quantum Internet:
Data Plane Applications using Quantum Internet:
Applications may also be classified by the industry sector that they serve. For example, applications may be classified as quantum computing, quantum meteorology, quantum chemistry, quantum cryptography, etc. This is a valid and useful classification scheme. However, since the classic Internet community is used to the control plane versus data plane paradigm we will primarily use that approach in this document.
The Quantum Internet will support a variety of applications and deployment configurations. This section details a few key use cases which illustrates the benefits of the Quantum Internet. In system engineering, a use case is typically made up of a set of possible sequences of interactions between nodes and users in a particular environment and related to a particular goal. This will be the definition that we use in this section.
In this scenario, two banks (i.e., Bank #1 and Bank #2) need to have secure communications for transmitting important financial transaction records (see Figure 1). For this purpose, they first need to securely exchange a classic secret cryptographic key (i.e., a sequence of classical bits), which is triggered by an end-user banker at Bank #1. This results in a source quantum node A at Bank #1 to securely send a classic secret key to a destination quantum node B at Bank #2. This is referred to as a secure communication setup. Note that the quantum node A and B could be either a bare-bone quantum end-node or a full-fledged quantum computer. This use case shows that the Quantum Internet can be leveraged to improve the security of classical Internet applications of which the financial application shown in Figure 1 is an example.
One requirement for this secure communication setup process is that it should not be vulnerable to any classic or quantum computing attack. This can be realized using QKD [ETSI-QKD-Interfaces]. QKD can securely distribute a secret key between two quantum nodes, without physically transmitting it through the network and thus achieving the required security. QKD is the most mature feature of the quantum information technology, and has been commercially deployed in small-scale and short-distance deployments. More QKD use cases have been described in ETSI GS QKD 002 [ETSI-QKD-UseCases].
In general, QKD (e.g., [BB84]) without using entanglement works as follows:
It is worth noting that:
As a result, the Quantum Internet in Figure 1 contains quantum channels. And in order to support secure communication setup especially in large-scale deployment, it also requires entanglement generation and entanglement distribution [I-D.van-meter-qirg-quantum-connection-setup], quantum repeaters/routers, and/or trusted QKD relays.
+---------------+
| End User |
|(e.g., Banking |
| Application) |
+---------------+
^
| User Interface
| (e.g., GUI)
V
+-----------------+ /--------\ +-----------------+
| |--->( Quantum )--->| |
| Source | ( Internet ) | Destination |
| Quantum | \--------/ | Quantum |
| Node A | | Node B |
| (e.g., Bank #1) | /--------\ | (e.g., Bank #2) |
| | ( Classical) | |
| |<-->( Internet )<-->| |
+-----------------+ \--------/ +-----------------+
Figure 1: Secure Communication Setup
In this scenario, Noisy Intermediate-Scale Quantum (NISQ) computers distributed in different locations are available for sharing. According to the definition in [Preskill], a NISQ computer can only realize a small number of qubits and has limited quantum error correction. In order to gain higher computation power before fully-fledged quantum computers become available, NISQ computers can be connected via classic and quantum channels. This scenario is referred to as distributed quantum computing [Caleffi] [Cacciapuoti01] [Cacciapuoti02]. This use case reflects the vastly increased computing power which quantum computers as a part of the Quantum Internet can bring, in contrast to classical computers in the classical Internet.
As an example, scientists can leverage these connected NISQ computer to solve highly complex scientific computation problems such as analysis of chemical interactions for medical drug development (see Figure 2). In this case, qubits will be transmitted among connected quantum computers via quantum channels, while classic control messages will be transmitted among them via classic channels for coordination and control purpose . Qubits from one NISQ computer to another NISQ computer are very sensitive and cannot be lost. For this purpose, quantum teleportation can be leveraged to teleport sensitive data qubits from one quantum computer A to another quantum computer B. Note that Figure 2 does not cover measurement-based distributed quantum computing, where quantum teleportation may not be required.
Specifically, the following steps happen between A and B:
In Figure 2, the Quantum Internet contains quantum channels and quantum repeaters/routers [I-D.irtf-qirg-principles]. This use case needs to support entanglement generation in order to enable quantum teleportation, entanglement distribution or quantum connection setup [I-D.van-meter-qirg-quantum-connection-setup] in order to support long-distance quantum teleportation.
+-----------------+
| End-User |
|(e.g., Scientist)|
+-----------------+
^
|User Interface (e.g. GUI)
|
+------------------+-------------------+
| |
| |
V V
+----------------+ /--------\ +----------------+
| |--->( Quantum )--->| |
| | ( Internet ) | |
| Quantum | \--------/ | Quantum |
| Computer A | | Computer B |
| (e.g., Site #1)| /--------\ | (e.g., Site #2)|
| | ( Classical) | |
| |<-->( Internet )<-->| |
+----------------+ \--------/ +----------------+
Figure 2: Distributed Quantum Computing
Secure computation with privacy preservation refers to the scenario:
As an example illustrated in Figure 3, the client node could be a virtual voice-controlled home assistant device like Amazon's Alexa product. The remote computation node could be a quantum computer in the cloud. A resident as an end-user uses voice to control the home device. The home device captures voice-based commands from the end-user. Then, the home device interfaces to a home quantum terminal node (e.g., a home gateway), which interacts with the remote computation node to perform computation over the captured voice-based commands. The home quantum terminal could be either a bare-bone quantum end-node or a full-fledged quantum computer.
In this particular case, there is no privacy concern since the source data (i.e., captured voice-based commands) will not be sent to the remote computation node which could be compromised. Protocols [Fitzsimons] for delegated quantum computing or blind quantum computation can be leveraged to realize secure delegated computation and guarantee privacy preservation simultaneously. Using delegated quantum computing protocols, the client node does not need send the source data but qubits with some measurement instructions to the remote computation node (e.g., a quantum computer).
After receiving qubits and measurement instructions, the remote computation node performs the following actions:
In Figure 3, the Quantum Internet contains quantum channels and quantum repeaters/routers for long-distance qubits transmission [I-D.irtf-qirg-principles].
+----------------+
| End-User |
|(e.g., Resident)|
+----------------+
^
| User Interface
| (e.g., voice commands)
V
+----------------+
| Home Device |
+----------------+
^
| Classic
| Channel
V
+----------------+ /--------\ +----------------+
| |--->( Quantum )--->| |
| Quantum | ( Internet ) | Remote |
| Terminal | \--------/ | Computation |
| Node | | Node |
| (e.g., Home | /--------\ | (e.g., QC |
| Gateway) | ( Classical) | in Cloud) |
| |<-->( Internet )<-->| |
+----------------+ \--------/ +----------------+
Figure 3: Secure Computation with Privacy Preservation
Based on the above use cases, some general requirements on the Quantum Internet from the networking perspective are introduced below:
This document provides an overview of some expected applications for the Quantum Internet and details selected use cases. The applications are classified as either control plane or data plane functionality as typical for Internet applications. One key take away is that a variety of control plane applications will run on the Quantum Internet. In contrast, the data plane applications running on the Quantum Internet will be focused on supporting different forms of remote quantum computing. This set of applications may, of course, naturally expand over time as the Quantum Internet matures.
This document can also serve as an introductory text to persons interested in learning about the practical uses of the Quantum Internet. Finally, it is hoped that this document will help guide further research and development of the specific Quantum Internet functionality required to implement the applications and uses cases described herein.
This document requests no IANA actions.
This document does not define an architecture nor a specific protocol for the Quantum Internet. It focuses on detailing use cases and describing typical Quantum Internet applications. However, some useful observations can be made regarding security as follows.
It has been clearly identified that once large-scale quantum computing becomes reality it will be able to theoretically break many of the public-key (i.e., asymmetric) cryptosystems currently in use because of the exponential increase of computing power with quantum computing. This would negatively affect many of the security mechanisms currently in use on the classic Internet. This has given strong impetus for starting development of new cryptographic systems that are secure against quantum computing attacks [NISTIR8240].
Paradoxically, development of a Quantum Internet will also mitigate the threats posed by quantum computing attacks against public-key cryptosystems. Specifically, the secure communication setup feature of the Quantum Internet as described in Section 5.1 will be strongly resistant to both classical and quantum computing attacks.
Finally, Section 5.3 provides a method to perform remote quantum computing while preserving the privacy of the source data.
The authors want to thank Xavier de Foy, Wojciech Kozlowski, Ruidong Li, and Gelard Patrick for their very useful reviews and comments to the document.