idnits 2.17.00 (12 Aug 2021) /tmp/idnits36469/draft-irtf-qirg-quantum-internet-use-cases-11.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- -- The document date (18 April 2022) is 26 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Unused Reference: 'Hill' is defined on line 1220, but no explicit reference was found in the text == Unused Reference: 'I-D.dahlberg-ll-quantum' is defined on line 1229, but no explicit reference was found in the text == Unused Reference: 'RFC2119' is defined on line 1326, but no explicit reference was found in the text == Unused Reference: 'Wang' is defined on line 1363, but no explicit reference was found in the text Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 QIRG C. Wang 3 Internet-Draft A. Rahman 4 Intended status: Informational InterDigital Communications, LLC 5 Expires: 20 October 2022 R. Li 6 Kanazawa University 7 M. Aelmans 8 Juniper Networks 9 K. Chakraborty 10 The University of Edinburgh 11 18 April 2022 13 Application Scenarios for the Quantum Internet 14 draft-irtf-qirg-quantum-internet-use-cases-11 16 Abstract 18 The Quantum Internet has the potential to improve application 19 functionality by incorporating quantum information technology into 20 the infrastructure of the overall Internet. This document provides 21 an overview of some applications expected to be used on the Quantum 22 Internet and categorizes them. Some general requirements for the 23 Quantum Internet are also discussed. The intent of this document is 24 to describe a framework for applications, and describe a few selected 25 application scenarios for the Quantum Internet. This document is a 26 product of the Quantum Internet Research Group (QIRG). 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at https://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on 20 October 2022. 45 Copyright Notice 47 Copyright (c) 2022 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 52 license-info) in effect on the date of publication of this document. 53 Please review these documents carefully, as they describe your rights 54 and restrictions with respect to this document. Code Components 55 extracted from this document must include Revised BSD License text as 56 described in Section 4.e of the Trust Legal Provisions and are 57 provided without warranty as described in the Revised BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 2. Terms and Acronyms List . . . . . . . . . . . . . . . . . . . 3 63 3. Quantum Internet Applications . . . . . . . . . . . . . . . . 6 64 3.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 6 65 3.2. Classification by Application Usage . . . . . . . . . . . 6 66 3.2.1. Quantum Cryptography Applications . . . . . . . . . . 7 67 3.2.2. Quantum Sensing/Metrology Applications . . . . . . . 7 68 3.2.3. Quantum Computing Applications . . . . . . . . . . . 8 69 4. Selected Quantum Internet Application Scenarios . . . . . . . 9 70 4.1. Secure Communication Setup . . . . . . . . . . . . . . . 9 71 4.2. Secure Quantum Computing with Privacy Preservation . . . 13 72 4.3. Distributed Quantum Computing . . . . . . . . . . . . . . 16 73 5. General Requirements . . . . . . . . . . . . . . . . . . . . 19 74 5.1. Background . . . . . . . . . . . . . . . . . . . . . . . 19 75 5.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 21 76 6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 22 77 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 78 8. Security Considerations . . . . . . . . . . . . . . . . . . . 23 79 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 80 10. Informative References . . . . . . . . . . . . . . . . . . . 25 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 83 1. Introduction 85 The Classical Internet has been constantly growing since it first 86 became commercially popular in the early 1990's. It essentially 87 consists of a large number of end-nodes (e.g., laptops, smart phones, 88 network servers) connected by routers and clustered in Autonomous 89 Systems. The end-nodes may run applications that provide service for 90 the end-users such as processing and transmission of voice, video or 91 data. The connections between the various nodes in the Internet 92 include backbone links (e.g., fiber optics) and access links (e.g., 93 WiFi, cellular wireless, Digital Subscriber Lines (DSLs)). Bits are 94 transmitted across the Classical Internet in packets. 96 Research and experiments have picked up over the last few years for 97 developing the Quantum Internet [Wehner]. End-nodes will also be 98 part of the Quantum Internet, in that case called quantum end-nodes 99 that may be connected by quantum repeaters/routers. These quantum 100 end-nodes will also run value-added applications which will be 101 discussed later. 103 The physical layer quantum channels between the various nodes in the 104 Quantum Internet can be either waveguides such as optical fibers or 105 free space. Photonic channels are particularly useful because light 106 (photons) is very suitable for physically realizing qubits. Qubits 107 are expected to be transferred across the Quantum Internet. The 108 Quantum Internet will operate according to quantum physical 109 principles such as quantum superposition and entanglement 110 [I-D.irtf-qirg-principles]. 112 The Quantum Internet is not anticipated to replace, but rather to 113 enhance the Classical Internet and/or provide breakthrough 114 applications. For instance, quantum key distribution can improve the 115 security of the Classical Internet; the powerful computation 116 capability of quantum computing can expedite and optimize 117 computation-intensive tasks (e.g., routing modelling) in the 118 Classical Internet. The Quantum Internet will run in conjunction 119 with the Classical Internet. The process of integrating the Quantum 120 Internet with the Classical Internet is similar to, but with more 121 profound implications, as the process of introducing any new 122 communication and networking paradigm into the existing Internet. 123 The intent of this document is to provide a common understanding and 124 framework of applications and application scenarios for the Quantum 125 Internet. 127 This document represents the consensus of the Quantum Internet 128 Research Group (QIRG). It has been reviewed extensively by Research 129 Group (RG) members with expertise in both quantum physics and 130 Classical Internet operation. 132 2. Terms and Acronyms List 134 This document assumes that the reader is familiar with the quantum 135 information technology related terms and concepts that are described 136 in [I-D.irtf-qirg-principles]. In addition, the following terms and 137 acronyms are defined herein for clarity: 139 * Bell Pairs - A special type of two-qubits quantum states. The two 140 qubits show a correlation that cannot be observed in classical 141 information theory. We refer to such correlation as quantum 142 entanglement. Bell pairs exhibit the maximal quantum 143 entanglement. One example of a Bell pair is 144 (|00>+|11>)/(Sqrt(2)). The Bell pairs are a fundamental resource 145 for quantum communication. 147 * Bit - Binary Digit (i.e., fundamental unit of information in 148 classical communications and classical computing). 150 * Classical Internet - The existing, deployed Internet (circa 2020) 151 where bits are transmitted in packets between nodes to convey 152 information. The Classical Internet supports applications which 153 may be enhanced by the Quantum Internet. For example, the end-to- 154 end security of a Classical Internet application may be improved 155 by secure communication setup using a quantum application. 157 * Entanglement Swapping: It is a process of sharing an entanglement 158 between two distant parties via some intermediate nodes. For 159 example, suppose there are three parties A, B, C, and each of the 160 parties (A, B) and (B, C) share Bell pairs. B can use the qubits 161 it shares with A and C to perform entanglement swapping 162 operations, and as a result, A and C share Bell pairs. 164 * Fast Byzantine Negotiation - A Quantum-based method for fast 165 agreement in Byzantine negotiations [Ben-Or] [Taherkhani]. 167 * Local Operations and Classical Communication (LOCC) - A method 168 where nodes communicate in rounds, in which (1) they can send any 169 classical information to each other; (2) they can perform local 170 quantum operations individually; and (3) the actions performed in 171 each round can depend on the results from previous rounds. 173 * Noisy Intermediate-Scale Quantum (NISQ) - NISQ was defined in 174 [Preskill] to represent a near-term era in quantum technology. 175 According to this definition, NISQ computers have two salient 176 features: (1) The size of NISQ computers range from 50 to a few 177 hundred physical qubits (i.e., intermediate-scale); and (2) Qubits 178 in NISQ computers have inherent errors and the control over them 179 is imperfect (i.e., noisy). 181 * Packet - A self-identified message with in-band addresses or other 182 information that can be used for forwarding the message. The 183 message contains an ordered set of bits of determinate number. 184 The bits contained in a packet are classical bits. 186 * Prepare-and-Measure - A set of Quantum Internet scenarios where 187 quantum nodes only support simple quantum functionalities (i.e., 188 prepare qubits and measure qubits). For example, BB84 [BB84] is a 189 prepare-and-measure quantum key distribution protocol. 191 * Quantum Computer (QC) - A quantum end-node that also has quantum 192 memory and quantum computing capabilities is regarded as a full- 193 fledged quantum computer. 195 * Quantum End-node - An end-node hosts user applications and 196 interfaces with the rest of the Internet. Typically, an end-node 197 may serve in a client, server, or peer-to-peer role as part of the 198 application. If the end-node is part of a Quantum Network (i.e, 199 is a quantum end-node), it must be able to generate/transfer and 200 receive/process qubits. A quantum end-node must also be able to 201 interface to the Classical Internet for control purposes and thus 202 also be able to receive, process, and transmit classical bits/ 203 packets. 205 * Quantum Internet - A network of Quantum Networks. The Quantum 206 Internet is expected to be merged into the Classical Internet. 207 The Quantum Internet may either improve classical applications or 208 may enable new quantum applications. 210 * Quantum Key Distribution (QKD) - A method that leverages quantum 211 mechanics such as no-cloning theorem to let two parties create the 212 same arbitrary classical key. 214 * Quantum Network - A new type of network enabled by quantum 215 information technology where quantum resources such as qubits and 216 entanglement are transferred and utilized between quantum nodes. 217 The Quantum Network will use both quantum channels, and classical 218 channels provided by the Classical Internet, referred to as a 219 hybrid implementation. 221 * Quantum Teleportation - A technique for transferring quantum 222 information via local operations and classical communication 223 (LOCC). If two parties share a Bell pair, then using quantum 224 teleportation a sender can transfer a quantum data bit to a 225 receiver without sending it physically via a quantum channel. 227 * Qubit - Quantum Bit (i.e., fundamental unit of information in 228 quantum communication and quantum computing). It is similar to a 229 classic bit in that the state of a qubit is either "0" or "1" 230 after it is measured, and is denoted as its basis state vector |0> 231 or |1>. However, the qubit is different than a classic bit in 232 that the qubit can be in a linear combination of both states 233 before it is measured and termed to be in superposition. Any of 234 several Degrees of Freedom (DOF) of a photon (e.g., polarization, 235 time bib, and/or frequency) or an electron (e.g., spin) can be 236 used to encode a qubit. 238 * Transmit a Qubit - An operation of encoding a qubit into a mobile 239 carrier (i.e., typically photon) and passing it through a quantum 240 channel from a sender (a transmitter) to a receiver. 242 * Teleport a Qubit - An operation on two or more carriers in 243 succession to move a qubit from a sender to a receiver using 244 quantum teleportation. 246 * Transfer a Qubit - An operation to move a qubit from a sender to a 247 receiver without specifying the means of moving the qubit, which 248 could be "transmit" or "teleport". 250 3. Quantum Internet Applications 252 3.1. Overview 254 The Quantum Internet is expected to be beneficial for a subset of 255 existing and new applications. The expected applications for the 256 Quantum Internet are still being developed as we are in the formative 257 stages of the Quantum Internet [Castelvecchi] [Wehner]. However, an 258 initial (and non-exhaustive) list of the applications to be supported 259 on the Quantum Internet can be identified and classified using two 260 different schemes. Note, this document does not include quantum 261 computing applications that are purely local to a given node (e.g., 262 quantum random number generator). 264 3.2. Classification by Application Usage 266 Applications may be grouped by the usage that they serve. 267 Specifically, applications may be grouped according to the following 268 categories: 270 * Quantum cryptography applications - Refer to the use of quantum 271 information technology for cryptographic tasks such as quantum key 272 distribution and quantum commitment. 274 * Quantum sensors applications - Refer to the use of quantum 275 information technology for supporting distributed sensors (e.g., 276 clock synchronization [Jozsa2000] [Komar] [Guo] ). 278 * Quantum computing applications - Refer to the use of quantum 279 information technology for supporting remote quantum computing 280 facilities (e.g., distributed quantum computing). 282 This scheme can be easily understood by both a technical and non- 283 technical audience. The next sections describe the scheme in more 284 detail. 286 3.2.1. Quantum Cryptography Applications 288 Examples of quantum cryptography applications include quantum-based 289 secure communication setup and fast Byzantine negotiation. 291 1. Secure communication setup - Refers to secure cryptographic key 292 distribution between two or more end-nodes. The most well-known 293 method is referred to as Quantum Key Distribution (QKD) [Renner], 294 which has been mathematically proven to be unbreakable. 296 2. Fast Byzantine negotiation - Refers to a Quantum-based method for 297 fast agreement in Byzantine negotiations [Ben-Or], for example, 298 to reduce the number of expected communication rounds and in turn 299 achieve faster agreement, in contrast to classical Byzantine 300 negotiations. A quantum aided Byzantine agreement on quantum 301 repeater networks as proposed in [Taherkhani] includes 302 optimization techniques to greatly reduce the quantum circuit 303 depth and the number of qubits in each node. Quantum-based 304 methods for fast agreement in Byzantine negotiations can be used 305 for improving consensus protocols such as practical Byzantine 306 Fault Tolerance(pBFT), as well as other distributed computing 307 features which use Byzantine negotiations. 309 3. Quantum money - The main security requirement of money is 310 unforgeability. A quantum money scheme aims to fulfill by 311 exploiting the no-cloning property of the unknown quantum states. 312 Though the original idea of quantum money dates back to 1970, 313 these early protocols allow only the issuing bank to verify a 314 quantum banknote. However, the recent protocols such as public- 315 key quantum money [Zhandry] allow anyone to verify the banknotes 316 locally. 318 3.2.2. Quantum Sensing/Metrology Applications 320 The entanglement, superposition, interference, squeezing properties 321 can enhance the sensitivity of the quantum sensors and eventually can 322 outperform the classical strategies. Examples of quantum sensor 323 applications include network clock synchronization, high sensitivity 324 sensing, etc. These applications mainly leverage a network of 325 entangled quantum sensors (i.e. quantum sensor networks) for high- 326 precision multi-parameter estimation [Proctor]. 328 1. Network clock synchronization - Refers to a world wide set of 329 atomic clocks connected by the Quantum Internet to achieve an 330 ultra precise clock signal [Komar] with fundamental precision 331 limits set by quantum theory. 333 2. High sensitivity sensing - Refers to applications that leverage 334 quantum phenomena to achieve reliable nanoscale sensing of 335 physical magnitudes. For example, [Guo] uses an entangled 336 quantum network for measuring the average phase shift among 337 multiple distributed nodes. 339 3. Interferometric Telescopes using Quantum Information - 340 Interferometric techniques are used to combine signals from two 341 or more telescopes to obtain measurements with higher resolution 342 than what could be obtained with either telescope individually. 343 It can make measurements of very small astronomical objects if 344 the telescopes are spread out over a wide area. However, the 345 phase fluctuations and photon loss introduced by the 346 communication channel between the telescopes put a limitation on 347 the baseline lengths of the optical interferometers. This 348 limitation can be potentially avoided using quantum 349 teleportation. In general, by sharing EPR-pairs using quantum 350 repeaters, the optical interferometers can communicate photons 351 over long distances, providing arbitrarily long baselines 352 [Gottesman2012]. 354 3.2.3. Quantum Computing Applications 356 In this section, we include the applications for the quantum 357 computing. Note that, for the next couple of years we will have 358 quantum computers as a cloud service. Sometimes, to run such 359 applications in the cloud while preserving the privacy, a client and 360 a server need to exchange qubits. Therefore, such privacy preserving 361 quantum computing applications require a Quantum Internet to execute. 363 Examples of quantum computing include distributed quantum computing 364 and secure quantum computing with privacy preservation, which can 365 enable new types of cloud computing. 367 1. Distributed quantum computing - Refers to a collection of remote 368 small-capacity quantum computers (i.e., each supporting a 369 relatively small number of qubits) that are connected and work 370 together in a coordinated fashion so as to simulate a virtual 371 large capacity quantum computer [Wehner]. 373 2. Secure quantum computing with privacy preservation - Refers to 374 private, or blind, quantum computation, which provides a way for 375 a client to delegate a computation task to one or more remote 376 quantum computers without disclosing the source data to be 377 computed over [Fitzsimons]. 379 4. Selected Quantum Internet Application Scenarios 381 The Quantum Internet will support a variety of applications and 382 deployment configurations. This section details a few key 383 application scenarios which illustrates the benefits of the Quantum 384 Internet. In system engineering, an application scenario is 385 typically made up of a set of possible sequences of interactions 386 between nodes and users in a particular environment and related to a 387 particular goal. This will be the definition that we use in this 388 section. 390 4.1. Secure Communication Setup 392 In this scenario, two banks (i.e., Bank #1 and Bank #2) need to have 393 secure communications for transmitting important financial 394 transaction records (see Figure 1). For this purpose, they first 395 need to securely share a classic secret cryptographic key (i.e., a 396 sequence of classical bits), which is triggered by an end-user banker 397 at Bank #1. This results in a source quantum node A at Bank #1 to 398 securely establish a classical secret key with a destination quantum 399 node B at Bank #2. This is referred to as a secure communication 400 setup. Note that the quantum node A and B may be either a bare-bone 401 quantum end-node or a full-fledged quantum computer. This 402 application scenario shows that the Quantum Internet can be leveraged 403 to improve the security of Classical Internet applications of which 404 the financial application shown in Figure 1 is an example. 406 One requirement for this secure communication setup process is that 407 it should not be vulnerable to any classical or quantum computing 408 attack. This can be realized using QKD which is unbreakable in 409 principle. QKD can securely establish a secret key between two 410 quantum nodes, using a classical authentication channel and insecure 411 quantum channel without physically transmitting the key through the 412 network and thus achieving the required security. However, care must 413 be taken to ensure that the QKD system is safe against physical side 414 channel attacks which can compromise the system. An example of a 415 physical side channel attack is to surreptitiously inject additional 416 light into the optical devices used in QKD to learn side information 417 about the system such as the polarization. Other specialized 418 physical attacks against QKD also use a classical authentication 419 channel and insecure quantum channel such as the phase-remapping 420 attack, photon number splitting attack, and decoy state attack 422 [Zhao2018]. QKD can be used for many other cryptographic 423 communications, such as IPSec and Transport Layer Security (TLS) 424 where involved parties need to establish a shared security key, 425 although it usually introduces a high latency. 427 QKD is the most mature feature of the quantum information technology, 428 and has been commercially released in small-scale and short-distance 429 deployments. More QKD use cases are described in ETSI documents 430 [ETSI-QKD-UseCases]; in addition, the ETSI document 431 [ETSI-QKD-Interfaces] specifies interfaces between QKD users and QKD 432 devices. 434 In general, the prepare and measure QKD protocols (e.g., [BB84]) 435 without using entanglement work as follows: 437 1. The source quantum node A encodes classical bits to qubits. 438 Basically, the source node A generates two random classical bit 439 strings X, Y. Among them, it uses the bit string X to choose the 440 basis and uses Y to choose the state corresponding to the chosen 441 basis. For example, if X=0 then in case of BB84 protocol Alice 442 prepares the state in {|0>, |1>}-basis; otherwise she prepares 443 the state in {|+>, |->}-basis. Similarly, if Y=0 then Alice 444 prepares the qubit either |0> or |+> (depending on the value of 445 X), and if Y =1, then Alice prepares the qubit either |1> or |->. 447 2. The source quantum node A sends qubits to the destination quantum 448 node B via quantum channel. 450 3. The destination quantum node receives qubits and measures each of 451 them in one of the two basis at random. 453 4. The destination quantum node informs the source node of its 454 choice of basis for each qubit. 456 5. The source quantum node informs the destination node which random 457 quantum basis is correct. 459 6. Both nodes discard any measurement bit under different quantum 460 basis and remaining bits could be used as the secret key. Before 461 generating the final secret key, there is a post-processing 462 procedure over authenticated classical channels. The classical 463 post-processing part can be subdivided into three steps, namely 464 parameter estimation, error-correction, and privacy 465 amplification. In the parameter estimation phase, both Alice and 466 Bob use some of the bits to estimate the channel error. If it is 467 larger than some threshold value, they abort the protocol 468 otherwise move to the error-correction phase. Basically, if an 469 eavesdropper tries to intercept and read qubits sent from node A 470 to node B, the eavesdropper will be detected due to the entropic 471 uncertainty relation property theorem of quantum mechanics. As a 472 part of the post-processing procedure, both nodes usually also 473 perform information reconciliation [Elkouss] for efficient error 474 correction and/or conduct privacy amplification [Tang] for 475 generating the final information-theoretical secure keys. 477 7. The post-processing procedure needs to be performed over an 478 authenticated classical channel. In other words, the source 479 quantum node and the destination quantum node need to 480 authenticate the classical channel to make sure there is no 481 eavesdroppers or man-in-the-middle attacks, according to certain 482 authentication protocols such as [Kiktenko]. In [Kiktenko], the 483 authenticity of the classical channel is checked at the very end 484 of the post-processing procedure instead of doing it for each 485 classical message exchanged between the quantum source node and 486 the quantum destination node. 488 It is worth noting that: 490 1. There are some entanglement-based QKD protocols, such as 491 [Treiber][E91][BBM92], which work differently than the above 492 steps. The entanglement-based schemes, where entangled states 493 are prepared externally to the source quantum node and the 494 destination quantum node, are not normally considered "prepare- 495 and-measure" as defined in [Wehner]; other entanglement-based 496 schemes, where entanglement is generated within the source 497 quantum node can still be considered "prepare-and-measure"; send- 498 and-return schemes can still be "prepare-and-measure", if the 499 information content, from which keys will be derived, is prepared 500 within the source quantum node before being sent to the 501 destination quantum node for measurement. 503 2. There are many enhanced QKD protocols based on [BB84]. For 504 example, a series of loopholes have been identified due to the 505 imperfections of measurement devices; there are several solutions 506 to take into account these attacks such as measurement-device- 507 independent QKD [Zhang2019]. These enhanced QKD protocols can 508 work differently than the steps of BB84 protocol [BB84]. 510 3. For large-scale QKD, QKD Networks (QKDN) are required, which can 511 be regarded as a subset of a Quantum Internet. A QKDN may 512 consist of a QKD application layer, a QKD network layer, and a 513 QKD link layer [Qin]. One or multiple trusted QKD relays 514 [Zhang2018] may exist between the source quantum node A and the 515 destination quantum node B, which are connected by a QKDN. 516 Alternatively, a QKDN may rely on entanglement distribution and 517 entanglement-based QKD protocols; as a result, quantum-repeaters/ 518 routers instead of trusted QKD relays are needed for large-scale 519 QKD. 521 4. QKD provides an information-theoretical way to share secret keys 522 between two parties in the presence of Eve. However, this is true 523 in theory, and there is a significant gap between theory and 524 practice. By exploiting the imperfection of the detectors Eve 525 can gain information about the shared key [Xu]. To avoid such 526 side-channel attacks in [Lo], the researchers provide a QKD 527 protocol called Measurement Device-Independent (MDI) QKD that 528 allows two users (a transmitter "Alice" and a receiver "Bob") to 529 communicate with perfect security, even if the (measurement) 530 hardware they are using has been tampered with (e.g., by an 531 eavesdropper) and thus is not trusted. It is achieved by 532 measuring correlations between signals from Alice and Bob rather 533 than the actual signals themselves. 535 5. QKD protocols based on Continuous Variable (CV-QKD) have recently 536 seen plenty of interest as they only require telecommunications 537 equipment that is readily available and is also in common use 538 industry-wide. This kind of technology is a potentially high- 539 performance technique for secure key distribution over limited 540 distances. The recent demonstration of CV-QKD shows 541 compatibility with classical coherent detection schemes that are 542 widely used for high bandwidth classical communication systems 543 [Grosshans]. Note that we still do not have a quantum repeater 544 for the continuous variable systems; hence, this kind of QKD 545 technologies can be used for the short distance communications or 546 trusted relay-based QKD networks. 548 6. Secret sharing can be used to distribute a secret key among 549 multiple nodes by letting each node know a share or a part of the 550 secret key, while no single node can know the entire secret key. 551 The secret key can only be re-constructed via collaboration from 552 a sufficient number of nodes. Quantum Secret Sharing (QSS) 553 typically refers to the scenario: The secret key to be shared is 554 based on quantum states instead of classical bits. QSS enables 555 to split and share such quantum states among multiple nodes. 557 As a result, the Quantum Internet in Figure 1 contains quantum 558 channels. And in order to support secure communication setup 559 especially in large-scale deployment, it also requires entanglement 560 generation and entanglement distribution 561 [I-D.van-meter-qirg-quantum-connection-setup], quantum repeaters/ 562 routers, and/or trusted QKD relays. 564 +---------------+ 565 | End User | 566 |(e.g., Banker) | 567 +---------------+ 568 ^ 569 | User Interface 570 | (e.g., GUI) 571 V 572 +-----------------+ /--------\ +-----------------+ 573 | |--->( Quantum )--->| | 574 | Source | ( Internet ) | Destination | 575 | Quantum | \--------/ | Quantum | 576 | Node A | | Node B | 577 | (e.g., Bank #1) | /--------\ | (e.g., Bank #2) | 578 | | ( Classical) | | 579 | |<-->( Internet )<-->| | 580 +-----------------+ \--------/ +-----------------+ 582 Figure 1: Secure Communication Setup 584 4.2. Secure Quantum Computing with Privacy Preservation 586 Secure computation with privacy preservation refers to the following 587 scenario: 589 1. A client node with source data delegates the computation of the 590 source data to a remote computation node (i.e. a server). 592 2. Furthermore, the client node does not want to disclose any source 593 data to the remote computation node, which preserves the source 594 data privacy. 596 3. Note that there is no assumption or guarantee that the remote 597 computation node is a trusted entity from the source data privacy 598 perspective. 600 As an example illustrated in Figure 2, a terminal node can be a small 601 quantum computer with limited computation capability compared to a 602 remote quantum computation node (e.g., a remote mainframe quantum 603 computer), but the terminal node needs to run a more computation- 604 intensive task (e.g., Shor's factoring algorithm). The terminal node 605 can create individual qubits and send them to the remote quantum 606 computation node. Then, the remote quantum computation node can 607 entangle the qubits, calculate on them, measure them, generate 608 measurement results in classical bits, and return the measurement 609 results to the terminal node. It is noted that those measurement 610 results will look like purely random data to the remote quantum 611 computation node because the initial states of the qubits were chosen 612 in a cryptographically secure fashion. 614 As a new client/server computation model, BQC generally enables: 1) 615 The client delegates a computation function to the server; 2) The 616 client does not send original qubits to the server, but send 617 transformed qubits to the server; 3) The computation function is 618 performed at the server on the transformed qubits to generate 619 temporary result qubits, which could be quantum-circuit-based 620 computation or measurement-based quantum computation. The server 621 sends the temporary result qubits to the client; 4) The client 622 receives the temporary result qubits and transforms them to the final 623 result qubits. During this process, the server can not figure out 624 the original qubits from the transformed qubits. Also, it will not 625 take too much efforts on the client side to transform the original 626 qubits to the transformed qubits, or transform the temporary result 627 qubits to the final result qubits. One of the very first BQC 628 protocols such as [Childs] follows this process, although the client 629 needs some basic quantum features such as quantum memory, qubit 630 preparation and measurement, and qubit transmission. Measurement- 631 based quantum computation is out of the scope of this document and 632 more details about it can be found in [Jozsa2005]. 634 It is worth noting that: 636 1. The BQC protocol in [Childs] is a circuit-based BQC model, where 637 the client only performs simple quantum circuit for qubit 638 transformation, while the server performs a sequence of quantum 639 logic gates. Qubits are transmitted back and forth between the 640 client and the server. 642 2. Universal BQC in [Broadbent] is a measurement-based BQC model, 643 which is based on measurement-based quantum computing leveraging 644 entangled states. The principle in UBQC is based on the fact the 645 quantum teleportation plus a rotated Bell measurement realizes a 646 quantum computation, which can be repeated multiple times to 647 realize a sequence of quantum computation. In this approach, the 648 client first prepares transformed qubits and sends them to the 649 server and the server needs first to prepare entangled states 650 from all received qubits. Then, multiple interaction and 651 measurement rounds happen between the client and the server. For 652 each round, the client computes and sends new measurement 653 instructions or measurement adaptations to the server; then, the 654 server performs the measurement according to the received 655 measurement instructions to generate measurement results (qubits 656 or in classic bits); the client receives the measurement results 657 and transforms them to the final results. 659 3. A hybrid universal BQC is proposed in [Zhang2009], where the 660 server performs both quantum circuits like [Childs] and quantum 661 measurements like [Broadbent] to reduce the number of required 662 entangled states in [Broadbent]. Also, the client is much 663 simpler than the client in [Childs]. This hybrid BQC is a 664 combination of circuit-based BQC model and measurement-based BQC 665 model. 667 4. It will be ideal if the client in BQC is a purely classical 668 client, which only needs to interact with the server using 669 classical channel and communications. [Huang] demonstrates such 670 an approach, where a classical client leverages two entangled 671 servers to perform BQC, with the assumption that both servers 672 cannot communicate with each other; otherwise, the blindness or 673 privacy of the client cannot be guaranteed. The scenario as 674 demonstrated in [Huang] is essentially an example of BQC with 675 multiple servers. 677 5. How to verify that the server will perform what the client 678 requests or expects is an important issue in many BQC protocols, 679 referred to as verifiable BQC. [Fitzsimons] discusses this issue 680 and compares it in various BQC protocols. 682 In Figure 2, the Quantum Internet contains quantum channels and 683 quantum repeaters/routers for long-distance qubits transmission 684 [I-D.irtf-qirg-principles]. 686 +----------------+ /--------\ +-------------------+ 687 | |--->( Quantum )--->| | 688 | | ( Internet ) | Remote Quantum | 689 | Terminal | \--------/ | Computation | 690 | Node | | Node | 691 | (e.g., A Small| /--------\ | (e.g., Remote | 692 | Quantum | ( Classical) | Mainframe) | 693 | Computer) |<-->( Internet )<-->| Quantum Computer)| 694 +----------------+ \--------/ +-------------------+ 696 Figure 2: Secure Quantum Computing with Privacy Preservation 698 4.3. Distributed Quantum Computing 700 There can be two types of distributed quantum computing [Denchev]: 702 1. Leverage quantum mechanics to enhance classical distributed 703 computing. For example, entangled quantum states can be 704 exploited to improve leader election in classical distributed 705 computing, by simply measuring the entangled quantum states at 706 each party (e.g., a node or a device) without introducing any 707 classical communications among distributed parties [Pal]. 708 Normally, pre-shared entanglement needs first be established 709 among distributed parties, followed by LOCC operations at each 710 party. And it generally does not need to transmit qubits among 711 distributed parties. 713 2. Distribute quantum computing functions to distributed quantum 714 computers. A quantum computing task or function (e.g., quantum 715 gates) is split and distributed to multiple physically separate 716 quantum computers. And it may or may not need to transmit qubits 717 (either inputs or outputs) among those distributed quantum 718 computers. Pre-shared entangled states may be needed to transmit 719 quantum states among distributed quantum computers without using 720 quantum communications, similar to quantum teleportation. For 721 example, [Gottesman1999] and [Eisert] have proved that a CNOT 722 gate can be realized jointly by and distributed to multiple 723 quantum computers. The rest of this section focuses on this type 724 of distributed quantum computing. 726 As a scenario for the second type of distributed quantum computing, 727 Noisy Intermediate-Scale Quantum (NISQ) computers distributed in 728 different locations are available for sharing. According to the 729 definition in [Preskill], a NISQ computer can only realize a small 730 number of qubits and has limited quantum error correction. In order 731 to gain higher computation power before fully-fledged quantum 732 computers become available, NISQ computers can be connected via 733 classical and quantum channels. This scenario is referred to as 734 distributed quantum computing [Caleffi] [Cacciapuoti2020] 735 [Cacciapuoti2019]. This application scenario reflects the vastly 736 increased computing power which quantum computers as a part of the 737 Quantum Internet can bring, in contrast to classical computers in the 738 Classical Internet, in the context of distributed quantum computing 739 ecosystem [Cuomo]. According to [Cuomo], quantum teleportation 740 enables a new communication paradigm, referred to as teledata 741 [VanMeter2006-01], which moves quantum states among qubits to 742 distributed quantum computers. In addition, distributed quantum 743 computation also needs the capability of remotely performing quantum 744 computation on qubits on distributed quantum computers, which can be 745 enabled by the technique called telegate [VanMeter2006-02]. 747 As an example, scientists can leverage these connected NISQ computer 748 to solve highly complex scientific computation problems, such as 749 analysis of chemical interactions for medical drug development [Cao] 750 (see Figure 3). In this case, qubits will be transmitted among 751 connected quantum computers via quantum channels, while classic 752 control messages will be transmitted among them via classical 753 channels for coordination and control purpose. Another example of 754 distributed quantum computing is secure Multi-Party Quantum 755 Computation (MPQC) [Crepeau], which can be regarded as a quantum 756 version of classical secure Multi-Party Computation (MPC). In a 757 secure MPQC protocol, multiple participants jointly perform quantum 758 computation on a set of input quantum states, which are prepared and 759 provided by different participants. One of the primary aims of the 760 secure MPQC is to guarantee that each participant will not know input 761 quantum states provided by other participants. Secure MPQC relies on 762 verifiable quantum secret sharing [Lipinska]. 764 For the example shown in Figure 3, qubits from one NISQ computer to 765 another NISQ computer are very sensitive and should not be lost. For 766 this purpose, quantum teleportation can be leveraged to teleport 767 sensitive data qubits from one quantum computer A to another quantum 768 computer B. Note that Figure 3 does not cover measurement-based 769 distributed quantum computing, where quantum teleportation may not be 770 required. When quantum teleportation is employed, the following 771 steps happen between A and B. In fact, LOCC [Chitambar] operations 772 are conducted at the quantum computers A and B in order to achieve 773 quantum teleportation as illustrated in Figure 3. 775 1. The quantum computer A locally generates some sensitive data 776 qubits to be teleported to the quantum computer B. 778 2. A shared entanglement is established between the quantum computer 779 A and the quantum computer B (i.e., there are two entangled 780 qubits: q1 at A and q2 at B). For example, the quantum computer 781 A can generate two entangled qubits (i.e., q1 and q2) and sends 782 q2 to the quantum computer B via quantum communications. 784 3. Then, the quantum computer A performs a Bell measurement of the 785 entangled qubit q1 and the sensitive data qubit. 787 4. The result from this Bell measurement will be encoded in two 788 classical bits, which will be physically transmitted via a 789 classical channel to the quantum computer B. 791 5. Based on the received two classical bits, the quantum computer B 792 modifies the state of the entangled qubit q2 in the way to 793 generate a new qubit identical to the sensitive data qubit at the 794 quantum computer A. 796 In Figure 3, the Quantum Internet contains quantum channels and 797 quantum repeaters/routers [I-D.irtf-qirg-principles]. This 798 application scenario needs to support entanglement generation and 799 entanglement distribution (or quantum connection) setup 800 [I-D.van-meter-qirg-quantum-connection-setup] in order to support 801 quantum teleportation. 803 +-----------------+ 804 | End-User | 805 |(e.g., Scientist)| 806 +-----------------+ 807 ^ 808 |User Interface (e.g. GUI) 809 | 810 +------------------+-------------------+ 811 | | 812 | | 813 V V 814 +----------------+ /--------\ +----------------+ 815 | |--->( Quantum )--->| | 816 | | ( Internet ) | | 817 | Quantum | \--------/ | Quantum | 818 | Computer A | | Computer B | 819 | (e.g., Site #1)| /--------\ | (e.g., Site #2)| 820 | | ( Classical) | | 821 | |<-->( Internet )<-->| | 822 +----------------+ \--------/ +----------------+ 823 Figure 3: Distributed Quantum Computing 825 5. General Requirements 827 5.1. Background 829 Quantum technologies are steadily evolving and improving. Therefore, 830 it is hard to predict the timeline and future milestones of quantum 831 technologies as pointed out in [Grumbling] for quantum computing. 832 Currently, a NISQ computer can achieve fifty to hundreds of qubits 833 with some given error rate. In fact, the error rates of two-qubit 834 quantum gates have decreased nearly in half every 1.5 years (for 835 trapped ion gates) to 2 years (for superconducting gates). The error 836 rate also increases as the number of qubits increases. For example, 837 a current 20-physical-qubit machine has a total error rate which is 838 close to the total error rate of a 7 year old two-qubit machine 839 [Grumbling]. 841 On the network level, six stages of Quantum Internet development are 842 described in [Wehner] as follows: 844 1. Trusted repeater networks (Stage-1) 846 2. Prepare and measure networks (Stage-2) 848 3. Entanglement distribution networks (Stage-3) 850 4. Quantum memory networks (Stage-4) 852 5. Fault-tolerant few qubit networks (Stage-5) 854 6. Quantum computing networks (Stage-6) 856 The first stage is simple trusted repeater networks, while the final 857 stage is the quantum computing networks where the full-blown Quantum 858 Internet will be achieved. Each intermediate stage brings with it 859 new functionality, new applications, and new characteristics. 860 Figure 4 illustrates Quantum Internet application scenarios as 861 described in this document mapped to the Quantum Internet stages 862 described in [Wehner]. For example, secure communication setup can 863 be supported in Stage-1, Stage-2, or Stage-3, but with different QKD 864 solutions. More specifically: 866 In Stage-1, basic QKD is possible and can be leveraged to support 867 secure communication setup but trusted nodes are required to provide 868 end-to-end security. The primary requirement is the trusted nodes. 870 In Stage-2, the end users can prepare and measure the qubits. In 871 this stage, the users can verify classical passwords without 872 revealing it. 874 In Stage-3, end-to-end security can be enabled based on quantum 875 repeaters and entanglement distribution, to support the same secure 876 communication setup application. The primary requirement is 877 entanglement distribution to enable long-distance QKD. 879 In Stage-4, the quantum repeaters gain the capability of storing and 880 manipulating entangled qubits in the quantum memories. Using these 881 kind of quantum networks, one can run sophisticated applications like 882 blind quantum computing, leader election, quantum secret sharing. 884 In Stage-5, quantum repeaters can perform error correction; hence 885 they can perform fault-tolerant quantum computations on the received 886 data. With the help of these repeaters, it is possible to run 887 distributed quantum computing and quantum sensor applications over a 888 smaller number of qubits. 890 Finally, in Stage-6, distributed quantum computing relying on more 891 qubits can be supported. 893 +---------+----------------------------+------------------------+ 894 | Quantum | Example Quantum | | 895 | Internet| Internet Use | Characteristic | 896 | Stage | Cases | | 897 +---------+----------------------------+------------------------+ 898 | Stage-1 | Secure comm setup | Trusted nodes | 899 | | using basic QKD | | 900 |---------------------------------------------------------------| 901 | Stage-2 | Secure comm setup | Prepare-and-measure | 902 | | using the QKD with | capability | 903 | | end-to-end security | | 904 |---------------------------------------------------------------| 905 | Stage-3 | Secure comm setup | Entanglement | 906 | | using entanglement-enabled | distribution | 907 | | QKD | | 908 |---------------------------------------------------------------| 909 | Stage-4 | Secure/blind quantum | Quantum memory | 910 | | computing | | 911 |---------------------------------------------------------------| 912 | Stage-5 | Higher-Accuracy Clock | Fault tolerance | 913 | | synchronization | | 914 |---------------------------------------------------------------| 915 | Stage-6 | Distributed quantum | More qubits | 916 | | computing | | 917 +---------------------------------------------------------------+ 919 Figure 4: Example Application Scenarios in Different Quantum 920 Internet Stages 922 5.2. Requirements 924 Some general and functional requirements on the Quantum Internet from 925 the networking perspective, based on the above application scenarios, 926 are identified as follows: 928 1. Methods for facilitating quantum applications to interact 929 efficiently with entangled qubits are necessary in order for them 930 to trigger distribution of designated entangled qubits to 931 potentially any other quantum node residing in the Quantum 932 Internet. To accomplish this, specific operations must be 933 performed on entangled qubits (e.g., entanglement swapping, 934 entanglement distillation). Quantum nodes may be quantum end- 935 nodes, quantum repeaters/routers, and/or quantum computers. 937 2. Quantum repeaters/routers should support robust and efficient 938 entanglement distribution in order to extend and establish high- 939 fidelity entanglement connection between two quantum nodes. For 940 achieving this, it is required to first generate an entangled 941 pair on each hop of the path between these two nodes, and then 942 perform entanglement swapping operations at each of the 943 intermediate nodes. 945 3. Quantum end-nodes must send additional information on classical 946 channels to aid in transferring qubits across quantum repeaters/ 947 receivers. This is because qubits are transferred individually 948 and do not have any associated packet header which can help in 949 transferring the qubit. Any extra information to aid in routing, 950 identification, etc., of the qubit(s) must be sent via classical 951 channels. 953 4. Methods for managing and controlling the Quantum Internet 954 including quantum nodes and their quantum resources are 955 necessary. The resources of a quantum node may include quantum 956 memory, quantum channels, qubits, established quantum 957 connections, etc. Such management methods can be used to monitor 958 network status of the Quantum Internet, diagnose and identify 959 potential issues (e.g. quantum connections), and configure 960 quantum nodes with new actions and/or policies (e.g. to perform a 961 new entanglement swapping operation). New management information 962 model for the Quantum Internet may need to be developed. 964 6. Conclusion 966 This document provides an overview of some expected application 967 categories for the Quantum Internet, and then details selected 968 application scenarios. The applications are first grouped by their 969 usage which is a natural and easy to understand classification 970 scheme. This set of applications may, of course, naturally expand 971 over time as the Quantum Internet matures. Finally, some general 972 requirements for the Quantum Internet are also provided. 974 This document can also serve as an introductory text to readers 975 interested in learning about the practical uses of the Quantum 976 Internet. Finally, it is hoped that this document will help guide 977 further research and development of the Quantum Internet 978 functionality required to implement the application scenarios 979 described herein. 981 7. IANA Considerations 983 This document requests no IANA actions. 985 8. Security Considerations 987 This document does not define an architecture nor a specific protocol 988 for the Quantum Internet. It focuses instead on detailing 989 application scenarios, requirements, and describing typical Quantum 990 Internet applications. However, some salient observations can be 991 made regarding security of the Quantum Internet as follows. 993 It has been identified in [NISTIR8240] that once large-scale quantum 994 computing becomes reality that it will be able to break many of the 995 public-key (i.e., asymmetric) cryptosystems currently in use. This 996 is because of the increase in computing ability with quantum 997 computers for certain classes of problems (e.g., prime factorization, 998 optimizations). This would negatively affect many of the security 999 mechanisms currently in use on the Classical Internet which are based 1000 on public-key (Diffie-Hellman) encryption. This has given strong 1001 impetus for starting development of new cryptographic systems that 1002 are secure against quantum computing attacks [NISTIR8240]. 1004 Interestingly, development of the Quantum Internet will also mitigate 1005 the threats posed by quantum computing attacks against Diffie-Hellman 1006 based public-key cryptosystems. Specifically, the secure 1007 communication setup feature of the Quantum Internet as described in 1008 Section 4.1 will be strongly resistant to both classical and quantum 1009 computing attacks against Diffie-Hellman based public-key 1010 cryptosystems. 1012 A key additional threat consideration for the Quantum Internet is 1013 pointed to by [RFC7258], which warns of the dangers of pervasive 1014 monitoring as a widespread attack on privacy. Pervasive monitoring 1015 is defined as a widespread, and usually covert, surveillance through 1016 intrusive gathering of application content or protocol metadata such 1017 as headers. This can be accomplished through active or passive 1018 wiretaps, traffic analysis, or subverting the cryptographic keys used 1019 to secure communications. 1021 The secure communication setup feature of the Quantum Internet as 1022 described in Section 4.1 will be strongly resistant to pervasive 1023 monitoring based on directly attacking (Diffie-Hellman) encryption 1024 keys. Also, Section 4.2 describes a method to perform remote quantum 1025 computing while preserving the privacy of the source data. Finally, 1026 the intrinsic property of qubits to decohere if they are observed, 1027 albeit covertly, will theoretically allow detection of unwanted 1028 monitoring in some future solutions. 1030 Modern networks are implemented with zero trust principles where 1031 classical cryptography is used for confidentiality, integrity 1032 protection, and authentication on many of the logical layers of the 1033 network stack, often all the way from device to software in the cloud 1034 [NISTSP800-207]. The cryptographic solutions in use today are based 1035 on well-understood primitives, provably secure protocols and state- 1036 of-the-art implementations that are secure against a variety of side- 1037 channel attacks. 1039 In contrast to conventional cryptography and Post-Quantum 1040 Cryptography (PQC), the security of QKD is inherently tied to the 1041 physical layer, which makes the threat surfaces of QKD and 1042 conventional cryptography quite different. QKD implementations have 1043 already been subjected to publicized attacks [Zhao2008] and the 1044 National Security Agency (NSA) notes that the risk profile of 1045 conventional cryptography is better understood [NSA]. The fact that 1046 conventional cryptography and PQC are implemented at a higher layer 1047 than the physical one means PQC can be used to securely send 1048 protected information through untrusted relays. This is in stark 1049 contrast with QKD, which relies on hop-by-hop security between 1050 intermediate trusted nodes. The PQC approach is better aligned with 1051 the modern technology environment, in which more applications are 1052 moving toward end-to-end security and zero-trust principles. It is 1053 also important to note that while PQC can be deployed as a software 1054 update, QKD requires new hardware. 1056 Regarding QKD implementation details, the NSA states that 1057 communication needs and security requirements physically conflict in 1058 QKD and that the engineering required to balance them has extremely 1059 low tolerance for error. While conventional cryptography can be 1060 implemented in hardware in some cases for performance or other 1061 reasons, QKD is inherently tied to hardware. The NSA points out that 1062 this makes QKD less flexible with regard to upgrades or security 1063 patches. As QKD is fundamentally a point-to-point protocol, the NSA 1064 also notes that QKD networks often require the use of trusted relays, 1065 which increases the security risk from insider threats. 1067 The UK's National Cyber Security Centre cautions against reliance on 1068 QKD, especially in critical national infrastructure sectors, and 1069 suggests that PQC as standardized by the NIST is a better solution 1070 [NCSC]. Meanwhile, the National Cybersecurity Agency of France has 1071 decided that QKD could be considered as a defense-in-depth measure 1072 complementing conventional cryptography, as long as the cost incurred 1073 does not adversely affect the mitigation of current threats to IT 1074 systems [ANNSI]. 1076 9. Acknowledgments 1078 The authors want to thank Michele Amoretti, Mathias Van Den Bossche, 1079 Xavier de Foy, Patrick Gelard, Alvaro Gomez Inesta, Wojciech 1080 Kozlowski, John Mattsson, Rodney Van Meter, Joey Salazar, and Joseph 1081 Touch, and the rest of the QIRG community as a whole for their very 1082 useful reviews and comments to the document. 1084 10. Informative References 1086 [ANNSI] "Should Quantum Key Distribution be Used for Secure 1087 Communications?", Technical Position Paper, French 1088 National Cybersecurity Agency (ANSSI), 2020, 1089 . 1092 [BB84] Bennett, C. H. and G. Brassard, "Quantum Cryptography: 1093 Public Key Distribution and Coin Tossing", 1984, 1094 . 1097 [BBM92] Bennett, C.H., Brassard, G., and N.D. Mermin, "Quantum 1098 Cryptography without Bell's Theorem", Physical Review 1099 Letter, American Physical Society, 1992, 1100 . 1102 [Ben-Or] Ben-Or, M. and A. 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Phys, 2018, 1410 . 1413 Authors' Addresses 1415 Chonggang Wang 1416 InterDigital Communications, LLC 1417 1001 E Hector St 1418 Conshohocken, 19428 1419 United States of America 1420 Email: Chonggang.Wang@InterDigital.com 1422 Akbar Rahman 1423 InterDigital Communications, LLC 1424 1000 Sherbrooke Street West 1425 Montreal H3A 3G4 1426 Canada 1427 Email: rahmansakbar@yahoo.com 1429 Ruidong Li 1430 Kanazawa University 1431 Kakuma-machi, 1432 Ishikawa Prefecture 920-1192 1433 Japan 1434 Email: lrd@se.kanazawa-u.ac.jp 1436 Melchior Aelmans 1437 Juniper Networks 1438 Boeing Avenue 240 1439 Schiphol-Rijk 1440 Email: maelmans@juniper.net 1441 Kaushik Chakraborty 1442 The University of Edinburgh 1443 10 Crichton Street 1444 Edinburgh 1445 EH8 9AB, Scotland 1446 United Kingdom 1447 Email: kchakrab@exseed.edu.ac.uk