{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,4]],"date-time":"2026-06-04T11:12:32Z","timestamp":1780571552641,"version":"3.54.1"},"reference-count":133,"publisher":"Association for Computing Machinery (ACM)","issue":"4","license":[{"start":{"date-parts":[[2020,8,20]],"date-time":"2020-08-20T00:00:00Z","timestamp":1597881600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.acm.org\/publications\/policies\/copyright_policy#Background"}],"funder":[{"DOI":"10.13039\/100008982","name":"Qatar National Research Fund","doi-asserted-by":"publisher","award":["NPRP 11S-0109-180242"],"award-info":[{"award-number":["NPRP 11S-0109-180242"]}],"id":[{"id":"10.13039\/100008982","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["dl.acm.org"],"crossmark-restriction":true},"short-container-title":["ACM Comput. Surv."],"published-print":{"date-parts":[[2021,7,31]]},"abstract":"<jats:p>Cryptographic algorithms have been used not only to create robust ciphertexts but also to generate cryptograms that, contrary to the classic goal of cryptography, are meant to be broken. These cryptograms, generally called puzzles, require the use of a certain amount of resources to be solved, hence introducing a cost that is often regarded as a time delay\u2014though it could involve other metrics as well, such as bandwidth. These powerful features have made puzzles the core of many security protocols, acquiring increasing importance in the IT security landscape. The concept of a puzzle has subsequently been extended to other types of schemes that do not use cryptographic functions, such as CAPTCHAs, which are used to discriminate humans from machines. Overall, puzzles have experienced a renewed interest with the advent of Bitcoin, which uses a CPU-intensive puzzle as proof of work. In this article, we provide a comprehensive study of the most important puzzle construction schemes available in the literature, categorizing them according to several attributes, such as resource type, verification type, and applications. We have redefined the term puzzle by collecting and integrating the scattered notions used in different works, to cover all the existing applications. Moreover, we provide an overview of the possible applications, identifying key requirements and different design approaches. Finally, we highlight the features and limitations of each approach, providing a useful guide for the future development of new puzzle schemes.<\/jats:p>","DOI":"10.1145\/3396374","type":"journal-article","created":{"date-parts":[[2020,7,7]],"date-time":"2020-07-07T12:38:30Z","timestamp":1594125510000},"page":"1-38","update-policy":"https:\/\/doi.org\/10.1145\/crossmark-policy","source":"Crossref","is-referenced-by-count":34,"title":["Foundations, Properties, and Security Applications of Puzzles"],"prefix":"10.1145","volume":"53","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2689-348X","authenticated-orcid":false,"given":"Isra Mohamed","family":"Ali","sequence":"first","affiliation":[{"name":"Hamad Bin Khalifa University (HBKU), College of Science and Engineering (CSE), Division of Information and Computing Technology (ICT), Doha, Qatar"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8237-0539","authenticated-orcid":false,"given":"Maurantonio","family":"Caprolu","sequence":"additional","affiliation":[{"name":"Hamad Bin Khalifa University (HBKU), College of Science and Engineering (CSE), Division of Information and Computing Technology (ICT), Doha, Qatar"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1909-0336","authenticated-orcid":false,"given":"Roberto Di","family":"Pietro","sequence":"additional","affiliation":[{"name":"Hamad Bin Khalifa University (HBKU), College of Science and Engineering (CSE), Division of Information and Computing Technology (ICT), Doha, Qatar"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"320","published-online":{"date-parts":[[2020,8,20]]},"reference":[{"key":"e_1_2_1_1_1","doi-asserted-by":"publisher","DOI":"10.1145\/1064340.1064341"},{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1109\/ACSAC.2009.33"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-56617-7_2"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-70500-2_17"},{"key":"e_1_2_1_5_1","doi-asserted-by":"publisher","DOI":"10.1145\/3176258.3176327"},{"key":"e_1_2_1_6_1","volume-title":"Proceedings of the IEEE International Conference on Software Quality, Reliability and Security Companion (QRS-C\u201918)","author":"Amoretti M."},{"key":"e_1_2_1_8_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-10879-7_31"},{"key":"e_1_2_1_9_1","volume-title":"Proceedings of the International Workshop on Security Protocols. Springer, 170--177","author":"Aura Tuomas","year":"2000"},{"key":"e_1_2_1_10_1","unstructured":"Adam Back. 2002. Hashcash - A denial of service counter-measure. Retrieved from http:\/\/citeseerx.ist.psu.edu\/viewdoc\/summary?doi=10.1.1.15.8.  Adam Back. 2002. Hashcash - A denial of service counter-measure. Retrieved from http:\/\/citeseerx.ist.psu.edu\/viewdoc\/summary?doi=10.1.1.15.8."},{"key":"e_1_2_1_11_1","doi-asserted-by":"publisher","DOI":"10.1109\/ICDAR.2003.1227619"},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-96884-1_26"},{"key":"e_1_2_1_13_1","volume-title":"Proceedings of the Conference on Advances in Cryptology (CRYPTO\u201909)","author":"Barak Boaz","year":"2009"},{"key":"e_1_2_1_14_1","volume-title":"Keromytis","author":"Barbera Marco Valerio","year":"2013"},{"key":"e_1_2_1_15_1","doi-asserted-by":"publisher","DOI":"10.1109\/EuroSP.2016.31"},{"key":"e_1_2_1_16_1","volume-title":"Proceedings of the USENIX Security Symposium. 315--326","author":"Biryukov Alex","year":"2016"},{"key":"e_1_2_1_17_1","doi-asserted-by":"publisher","DOI":"10.5195\/LEDGER.2017.48"},{"key":"e_1_2_1_18_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-53644-5_20"},{"key":"e_1_2_1_19_1","unstructured":"M. Blum L. A. Von Ahn J. Langford and N. Hopper. 2000. The captcha project (completely automatic public turing test to tell computers and humans apart). School of Computer Science Carnegie-Mellon University. Retrieved from http:\/\/www.captcha.net.  M. Blum L. A. Von Ahn J. Langford and N. Hopper. 2000. The captcha project (completely automatic public turing test to tell computers and humans apart). School of Computer Science Carnegie-Mellon University. Retrieved from http:\/\/www.captcha.net."},{"key":"e_1_2_1_20_1","doi-asserted-by":"publisher","DOI":"10.1109\/MC.2004.1297298"},{"key":"e_1_2_1_21_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-96884-1_25"},{"key":"e_1_2_1_22_1","volume-title":"Proceedings of the IEEE Symposium on Security and Privacy (SP\u201915)","author":"Bonneau Joseph"},{"key":"e_1_2_1_23_1","doi-asserted-by":"publisher","DOI":"10.1109\/P2P.2006.10"},{"key":"e_1_2_1_24_1","volume-title":"2018 IEEE International Conference on Software Quality, Reliability and Security Companion (QRS-C'18)","author":"Amoretti M."},{"key":"e_1_2_1_25_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-22792-9_22"},{"key":"e_1_2_1_26_1","volume-title":"Proceedings of the 8th USENIX Workshop on Offensive Technologies (WOOT\u201914)","author":"Bursztein Elie"},{"key":"e_1_2_1_27_1","doi-asserted-by":"publisher","DOI":"10.1109\/SP.2010.31"},{"key":"e_1_2_1_28_1","doi-asserted-by":"publisher","DOI":"10.1109\/SCT.1993.336546"},{"key":"e_1_2_1_29_1","doi-asserted-by":"publisher","DOI":"10.1109\/IPDS.1998.707724"},{"key":"e_1_2_1_30_1","volume-title":"Proceedings of the IEEE International Conference on Edge Computing (EDGE\u201919)","author":"Caprolu M.","year":"2019"},{"key":"e_1_2_1_31_1","doi-asserted-by":"publisher","DOI":"10.5555\/648025.744369"},{"key":"e_1_2_1_32_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-10366-7_30"},{"key":"e_1_2_1_33_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-78375-8_15"},{"key":"e_1_2_1_34_1","unstructured":"Wei Dai. 1998. B-money proposal. White Paper.  Wei Dai. 1998. B-money proposal. White Paper."},{"key":"e_1_2_1_35_1","unstructured":"Dancho Danchev. 2008. Inside India\u2019s CAPTCHA solving economy. Retrieved from https:\/\/www.zdnet.com\/article\/inside-indias-captcha-solving-economy\/.  Dancho Danchev. 2008. Inside India\u2019s CAPTCHA solving economy. Retrieved from https:\/\/www.zdnet.com\/article\/inside-indias-captcha-solving-economy\/."},{"key":"e_1_2_1_36_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.joule.2018.04.016"},{"key":"e_1_2_1_37_1","volume-title":"Proceedings of the USENIX Security Symposium","volume":"42","author":"Dean Drew","year":"2001"},{"key":"e_1_2_1_38_1","doi-asserted-by":"publisher","DOI":"10.21236\/ADA465464"},{"key":"e_1_2_1_39_1","volume-title":"Rubin","author":"Doshi Sujata","year":"2006"},{"key":"e_1_2_1_40_1","doi-asserted-by":"publisher","DOI":"10.5555\/646334.687813"},{"key":"e_1_2_1_41_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-540-45146-4_25"},{"key":"e_1_2_1_42_1","volume-title":"Proceedings of the Annual International Cryptology Conference. Springer, 139--147","author":"Dwork Cynthia","year":"1992"},{"key":"e_1_2_1_43_1","doi-asserted-by":"publisher","DOI":"10.1007\/11535218_3"},{"key":"e_1_2_1_44_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-48000-7_29"},{"key":"e_1_2_1_45_1","doi-asserted-by":"publisher","DOI":"10.1145\/3212998"},{"key":"e_1_2_1_46_1","doi-asserted-by":"publisher","DOI":"10.1109\/MSPEC.2017.8048837"},{"key":"e_1_2_1_47_1","volume-title":"Proceedings of the ACM SIGCOMM Computer Communication Review","volume":"33","year":"2003"},{"key":"e_1_2_1_48_1","volume-title":"Proceedings of the 24th Annual Joint Conference of the IEEE Computer and Communications Societies (INFOCOM\u201905)","volume":"4","author":"Kaiser E.","year":"2005"},{"key":"e_1_2_1_49_1","volume-title":"Franklin and Dahlia Malkhi","author":"Matthew","year":"1997"},{"key":"e_1_2_1_50_1","doi-asserted-by":"publisher","DOI":"10.1145\/2818000.2818006"},{"key":"e_1_2_1_51_1","volume-title":"Network Security, Scott C.-H. Huang, David MacCallum, and Ding-Zhu Du (Eds.)","author":"Gao Yi"},{"key":"e_1_2_1_52_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-46803-6_10"},{"key":"e_1_2_1_54_1","volume-title":"Proceedings of the International Workshop on Security Protocols. Springer, 80--96","author":"Gligor Virgil D.","year":"2003"},{"key":"e_1_2_1_55_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.future.2012.08.013"},{"key":"e_1_2_1_56_1","volume-title":"Proceedings of the 3rd Romanian-Hungarian Joint Symposium on Applied Computational Intelligence (SACI\u201906)","author":"Groza Bogdan","year":"2006"},{"key":"e_1_2_1_57_1","volume-title":"Proceedings of the IEEE International Symposium on Performance Analysis of Systems and Software (ISPASS\u201919)","author":"Han R.","year":"2019"},{"key":"e_1_2_1_58_1","doi-asserted-by":"publisher","DOI":"10.1016\/B978-0-12-385510-7.00003-5"},{"key":"e_1_2_1_59_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-53890-6_24"},{"key":"e_1_2_1_60_1","doi-asserted-by":"publisher","DOI":"10.1109\/ISBAST.2012.17"},{"key":"e_1_2_1_61_1","volume-title":"Secure Information Networks","author":"Jakobsson Markus"},{"key":"e_1_2_1_62_1","doi-asserted-by":"publisher","DOI":"10.1109\/CIT.2010.193"},{"key":"e_1_2_1_63_1","volume-title":"Proceedings of the Network and Distributed System Security Symposium (NDSS\u201999)","volume":"99","author":"Juels Ari"},{"key":"e_1_2_1_64_1","doi-asserted-by":"publisher","DOI":"10.1109\/INFOCOM.2008.4544602"},{"key":"e_1_2_1_65_1","doi-asserted-by":"publisher","DOI":"10.1145\/3339252.3341498"},{"key":"e_1_2_1_66_1","volume-title":"Proceedings of the European Symposium on Research in Computer Security. Springer, 679--697","author":"Ghassan"},{"key":"e_1_2_1_68_1","volume-title":"Proceedings of the Conference on Usable Software and Interface Design","volume":"2","author":"Khot Rohit Ashok","year":"2009"},{"key":"e_1_2_1_69_1","doi-asserted-by":"publisher","DOI":"10.1109\/ICDCS.2018.00051"},{"key":"e_1_2_1_70_1","doi-asserted-by":"publisher","DOI":"10.1145\/358790.358797"},{"key":"e_1_2_1_71_1","volume-title":"Proceedings of the Workshop on Economics and Information Security.","author":"Laurie Ben","year":"2004"},{"key":"e_1_2_1_72_1","doi-asserted-by":"publisher","DOI":"10.1145\/2207676.2208385"},{"key":"e_1_2_1_73_1","doi-asserted-by":"publisher","DOI":"10.1109\/IMF.2018.00016"},{"key":"e_1_2_1_74_1","first-page":"2","volume-title":"Litecoin-open source","author":"Lee Charles"},{"key":"e_1_2_1_75_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF01457454"},{"key":"e_1_2_1_76_1","doi-asserted-by":"publisher","DOI":"10.1145\/2382536.2382548"},{"key":"e_1_2_1_77_1","first-page":"195","article-title":"Method for selectively restricting access to computer systems","volume":"6","author":"Lillibridge Mark D.","year":"2001","journal-title":"U.S. Patent"},{"key":"e_1_2_1_78_1","doi-asserted-by":"publisher","DOI":"10.1109\/FOCS.2017.59"},{"key":"e_1_2_1_79_1","volume-title":"5th Annual Workshop on the Economics of Information Security (WEIS'16)","author":"Liu Debin","year":"2006"},{"key":"e_1_2_1_80_1","doi-asserted-by":"publisher","DOI":"10.1109\/ACCESS.2018.2826518"},{"key":"e_1_2_1_82_1","volume-title":"Mathematical puzzles","author":"Loyd Sam"},{"key":"e_1_2_1_83_1","doi-asserted-by":"publisher","DOI":"10.1109\/CSF.2015.34"},{"key":"e_1_2_1_84_1","doi-asserted-by":"publisher","DOI":"10.1109\/ITCC.2005.200"},{"key":"e_1_2_1_85_1","doi-asserted-by":"publisher","DOI":"10.1145\/2422436.2422479"},{"key":"e_1_2_1_86_1","article-title":"The impact of quantum computing on present cryptography","volume":"9","author":"Mavroeidis Vasileios","year":"2018","journal-title":"Int. J. Adv. Comput. Sci. Appl."},{"key":"e_1_2_1_87_1","volume-title":"Dept. Elect. Comput. Eng.","author":"McNevin Timothy J."},{"key":"e_1_2_1_88_1","doi-asserted-by":"publisher","DOI":"10.1145\/359460.359473"},{"key":"e_1_2_1_89_1","doi-asserted-by":"publisher","DOI":"10.1145\/2702123.2702127"},{"key":"e_1_2_1_90_1","doi-asserted-by":"publisher","DOI":"10.1109\/SP.2014.37"},{"key":"e_1_2_1_91_1","doi-asserted-by":"publisher","DOI":"10.1145\/2810103.2813621"},{"key":"e_1_2_1_92_1","volume-title":"LaViola Jr","author":"Miller Andrew","year":"2014"},{"key":"e_1_2_1_93_1","doi-asserted-by":"publisher","DOI":"10.1109\/CVPR.2003.1211347"},{"key":"e_1_2_1_95_1","volume-title":"Proceedings of the USENIX Security Symposium","volume":"10","author":"Motoyama Marti","year":"2010"},{"key":"e_1_2_1_96_1","volume-title":"Bitcoin: A peer-to-peer electronic cash system. Manubot.","author":"Nakamoto Satoshi","year":"2019"},{"key":"e_1_2_1_97_1","unstructured":"Moni Naor. 1996. Verification of a human in the loop or identification via the turing test. Retrieved from http:\/\/www.wisdom.weizmann.ac.il\/~naor\/PAPERS\/humanabs.html.  Moni Naor. 1996. Verification of a human in the loop or identification via the turing test. Retrieved from http:\/\/www.wisdom.weizmann.ac.il\/~naor\/PAPERS\/humanabs.html."},{"key":"e_1_2_1_98_1","doi-asserted-by":"publisher","DOI":"10.1145\/3132259"},{"key":"e_1_2_1_99_1","volume-title":"2019 49th Annual IEEE\/IFIP International Conference on Dependable Systems and Networks (DSN'19)","author":"Noureddine M. A."},{"key":"e_1_2_1_101_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jalgor.2003.12.002"},{"key":"e_1_2_1_102_1","doi-asserted-by":"publisher","DOI":"10.1145\/1282427.1282413"},{"key":"e_1_2_1_103_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-56614-6_22"},{"key":"e_1_2_1_104_1","unstructured":"Colin Percival. 2009. Stronger key derivation via sequential memory-hard functions. BSDCan.  Colin Percival. 2009. Stronger key derivation via sequential memory-hard functions. BSDCan."},{"key":"e_1_2_1_105_1","doi-asserted-by":"publisher","DOI":"10.1145\/2073290.2073302"},{"key":"e_1_2_1_106_1","volume-title":"Simple verifiable delay functions.IACR Cryptol. ePrint Arch. 2018","author":"Pietrzak Krzysztof","year":"2018"},{"key":"e_1_2_1_107_1","first-page":"495","article-title":"Spam reduction in real time communications by human interaction proof","volume":"8","author":"Ramanathan Rajesh","year":"2013","journal-title":"U.S. Patent"},{"key":"e_1_2_1_108_1","volume-title":"Proceedings of the International Conference on Information Security and Cryptology. Springer, 319--331","author":"Rangasamy Jothi","year":"2011"},{"key":"e_1_2_1_109_1","doi-asserted-by":"publisher","DOI":"10.1109\/TPDS.2010.57"},{"key":"e_1_2_1_110_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-10772-6_11"},{"key":"e_1_2_1_111_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.comcom.2009.11.009"},{"key":"e_1_2_1_112_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-53641-4_11"},{"key":"e_1_2_1_113_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-70500-2_16"},{"key":"e_1_2_1_114_1","volume-title":"Rivest and Adi Shamir","author":"Ronald","year":"1996"},{"key":"e_1_2_1_115_1","volume-title":"Wagner","author":"Rivest Ronald L.","year":"1996"},{"key":"e_1_2_1_116_1","doi-asserted-by":"publisher","DOI":"10.1109\/INFCOM.2007.328"},{"key":"e_1_2_1_117_1","doi-asserted-by":"publisher","DOI":"10.1109\/SFCS.1994.365700"},{"key":"e_1_2_1_118_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-02620-1_27"},{"key":"e_1_2_1_119_1","volume-title":"Proceedings of the 24th USENIX Security Symposium (USENIX\u201915)","author":"Sun Yixin","year":"2015"},{"key":"e_1_2_1_120_1","volume-title":"Bit gold, unenumerated. blogspot.com (Mar. 29","author":"Szabo Nick","year":"2006"},{"key":"e_1_2_1_121_1","volume-title":"On non-parallelizable deterministic client puzzle scheme with batch verification modes","author":"Tang Qiang"},{"key":"e_1_2_1_122_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-540-76969-9_16"},{"key":"e_1_2_1_123_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-662-48051-9_4"},{"key":"e_1_2_1_124_1","doi-asserted-by":"publisher","DOI":"10.1109\/COMST.2016.2535718"},{"key":"e_1_2_1_125_1","unstructured":"Nicolas Van Saberhagen. 2013. CryptoNote v 2.0.  Nicolas Van Saberhagen. 2013. CryptoNote v 2.0."},{"key":"e_1_2_1_126_1","doi-asserted-by":"publisher","DOI":"10.1007\/3-540-39200-9_18"},{"key":"e_1_2_1_127_1","volume-title":"recaptcha: Human-based character recognition via web security measures. Science 321, 5895","author":"Ahn Luis Von","year":"2008"},{"key":"e_1_2_1_128_1","doi-asserted-by":"publisher","DOI":"10.1007\/3-540-45708-9_19"},{"key":"e_1_2_1_129_1","doi-asserted-by":"publisher","DOI":"10.1145\/1731060.1731063"},{"key":"e_1_2_1_130_1","volume-title":"Zehui Xiong, Dusit Niyato, Ping Wang, Peizhao Hu, and Yonggang Wen.","author":"Wang Wenbo","year":"2018"},{"key":"e_1_2_1_131_1","volume-title":"Proceedings of the Symposium on Security and Privacy. IEEE, 78--92","author":"Wang XiaoFeng"},{"key":"e_1_2_1_132_1","volume-title":"Proceedings of the 11th ACM Conference on Computer and Communications Security (CCS\u201904)","author":"Wang XiaoFeng"},{"key":"e_1_2_1_133_1","volume-title":"Proceedings of the 11th ACM Conference on Computer and Communications Security. ACM, 246--256","author":"Waters Brent"},{"key":"e_1_2_1_134_1","first-page":"907","article-title":"Method for electing aggregator nodes in a network","volume":"7","author":"Westhoff Dirk","year":"2011","journal-title":"U.S. Patent"},{"key":"e_1_2_1_135_1","first-page":"1","article-title":"Ethereum: A secure decentralised generalised transaction ledger","volume":"151","author":"Wood Gavin","year":"2014","journal-title":"Ethereum Project Yellow Paper"},{"key":"e_1_2_1_136_1","volume-title":"Proceedings of the USENIX Security Symposium. 49--64","author":"Xu Yi"},{"key":"e_1_2_1_137_1","doi-asserted-by":"publisher","DOI":"10.1145\/1455770.1455839"},{"key":"e_1_2_1_138_1","doi-asserted-by":"publisher","DOI":"10.1145\/1408664.1408671"},{"key":"e_1_2_1_139_1","doi-asserted-by":"publisher","DOI":"10.1109\/TIFS.2012.2186294"}],"container-title":["ACM Computing Surveys"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/3396374","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/dl.acm.org\/doi\/pdf\/10.1145\/3396374","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,6,17]],"date-time":"2025-06-17T22:38:46Z","timestamp":1750199926000},"score":1,"resource":{"primary":{"URL":"https:\/\/dl.acm.org\/doi\/10.1145\/3396374"}},"subtitle":["A Survey"],"short-title":[],"issued":{"date-parts":[[2020,8,20]]},"references-count":133,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2021,7,31]]}},"alternative-id":["10.1145\/3396374"],"URL":"https:\/\/doi.org\/10.1145\/3396374","relation":{},"ISSN":["0360-0300","1557-7341"],"issn-type":[{"value":"0360-0300","type":"print"},{"value":"1557-7341","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,8,20]]},"assertion":[{"value":"2019-09-01","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2020-04-01","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2020-08-20","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}