{"id":"https://openalex.org/W180870158","doi":"https://doi.org/10.1016/b978-0-12-385510-7.00003-5","title":"CAPTCHAs","display_name":"CAPTCHAs","publication_year":2011,"publication_date":"2011-01-01","ids":{"openalex":"https://openalex.org/W180870158","doi":"https://doi.org/10.1016/b978-0-12-385510-7.00003-5","mag":"180870158"},"language":"en","primary_location":{"id":"doi:10.1016/b978-0-12-385510-7.00003-5","is_oa":false,"landing_page_url":"https://doi.org/10.1016/b978-0-12-385510-7.00003-5","pdf_url":null,"source":{"id":"https://openalex.org/S183285281","display_name":"Advances in computers","issn_l":"0065-2458","issn":["0065-2458"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320990","host_organization_name":"Elsevier BV","host_organization_lineage":["https://openalex.org/P4310320990"],"host_organization_lineage_names":["Elsevier BV"],"type":"book series"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Advances in Computers","raw_type":"book-chapter"},"type":"book-chapter","indexed_in":["crossref"],"open_access":{"is_oa":false,"oa_status":"closed","oa_url":null,"any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5016433443","display_name":"Jos\u00e9 Mar\u00eda G\u00f3mez Hidalgo","orcid":"https://orcid.org/0000-0001-7755-1896"},"institutions":[{"id":"https://openalex.org/I134820265","display_name":"Consejo Superior de Investigaciones Cient\u00edficas","ror":"https://ror.org/02gfc7t72","country_code":"ES","type":"government","lineage":["https://openalex.org/I134820265"]},{"id":"https://openalex.org/I4210095385","display_name":"Instituto de F\u00edsica Fundamental","ror":"https://ror.org/009wseg80","country_code":"ES","type":"facility","lineage":["https://openalex.org/I134820265","https://openalex.org/I4210095385"]}],"countries":["ES"],"is_corresponding":false,"raw_author_name":"Jos\u00e9 Mar\u00eda G\u00f3mez Hidalgo","raw_affiliation_strings":["Instituto de F\u00edsica Aplicada, Consejo Superior de Investigaciones Cient\u00edficas, Serrano 144, Madrid, Spain","Optenet, R&D Department, C/Jos\u00e9 Echegaray 8, edificio 3, Parque Empresarial Alvia, 28230 Las Rozas, Madrid Spain"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Instituto de F\u00edsica Aplicada, Consejo Superior de Investigaciones Cient\u00edficas, Serrano 144, Madrid, Spain","institution_ids":["https://openalex.org/I134820265","https://openalex.org/I4210095385"]},{"raw_affiliation_string":"Optenet, R&D Department, C/Jos\u00e9 Echegaray 8, edificio 3, Parque Empresarial Alvia, 28230 Las Rozas, Madrid Spain","institution_ids":[]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5070555024","display_name":"Gonzalo \u00c1lvarez","orcid":"https://orcid.org/0000-0002-8379-5595"},"institutions":[{"id":"https://openalex.org/I134820265","display_name":"Consejo Superior de Investigaciones Cient\u00edficas","ror":"https://ror.org/02gfc7t72","country_code":"ES","type":"government","lineage":["https://openalex.org/I134820265"]},{"id":"https://openalex.org/I4210095385","display_name":"Instituto de F\u00edsica Fundamental","ror":"https://ror.org/009wseg80","country_code":"ES","type":"facility","lineage":["https://openalex.org/I134820265","https://openalex.org/I4210095385"]}],"countries":["ES"],"is_corresponding":false,"raw_author_name":"Gonzalo Alvarez","raw_affiliation_strings":["Instituto de F\u00edsica Aplicada, Consejo Superior de Investigaciones Cient\u00edficas, Serrano 144, Madrid, Spain","Optenet, R&D Department, C/Jos\u00e9 Echegaray 8, edificio 3, Parque Empresarial Alvia, 28230 Las Rozas, Madrid Spain"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Instituto de F\u00edsica Aplicada, Consejo Superior de Investigaciones Cient\u00edficas, Serrano 144, Madrid, Spain","institution_ids":["https://openalex.org/I134820265","https://openalex.org/I4210095385"]},{"raw_affiliation_string":"Optenet, R&D Department, C/Jos\u00e9 Echegaray 8, edificio 3, Parque Empresarial Alvia, 28230 Las Rozas, Madrid Spain","institution_ids":[]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":2,"corresponding_author_ids":[],"corresponding_institution_ids":[],"apc_list":null,"apc_paid":null,"fwci":9.9867,"has_fulltext":false,"cited_by_count":32,"citation_normalized_percentile":{"value":0.97845601,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":89,"max":99},"biblio":{"volume":null,"issue":null,"first_page":"109","last_page":"181"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11800","display_name":"User Authentication and Security Systems","score":1.0,"subfield":{"id":"https://openalex.org/subfields/1710","display_name":"Information Systems"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T11800","display_name":"User Authentication and Security Systems","score":1.0,"subfield":{"id":"https://openalex.org/subfields/1710","display_name":"Information Systems"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11644","display_name":"Spam and Phishing Detection","score":0.9972000122070312,"subfield":{"id":"https://openalex.org/subfields/1710","display_name":"Information Systems"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11241","display_name":"Advanced Malware Detection Techniques","score":0.9966999888420105,"subfield":{"id":"https://openalex.org/subfields/1711","display_name":"Signal Processing"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/captcha","display_name":"CAPTCHA","score":0.9660429358482361},{"id":"https://openalex.org/keywords/turing-test","display_name":"Turing test","score":0.885719358921051},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.7693013548851013},{"id":"https://openalex.org/keywords/hacker","display_name":"Hacker","score":0.7027207612991333},{"id":"https://openalex.org/keywords/turing","display_name":"Turing","score":0.5559195876121521},{"id":"https://openalex.org/keywords/usability","display_name":"Usability","score":0.5360717177391052},{"id":"https://openalex.org/keywords/world-wide-web","display_name":"World Wide Web","score":0.5228163003921509},{"id":"https://openalex.org/keywords/field","display_name":"Field (mathematics)","score":0.49208277463912964},{"id":"https://openalex.org/keywords/test","display_name":"Test (biology)","score":0.4400450587272644},{"id":"https://openalex.org/keywords/computer-security","display_name":"Computer security","score":0.4292508661746979},{"id":"https://openalex.org/keywords/web-service","display_name":"Web service","score":0.4116551876068115},{"id":"https://openalex.org/keywords/human\u2013computer-interaction","display_name":"Human\u2013computer interaction","score":0.2675410211086273},{"id":"https://openalex.org/keywords/artificial-intelligence","display_name":"Artificial intelligence","score":0.24654647707939148},{"id":"https://openalex.org/keywords/programming-language","display_name":"Programming language","score":0.08530893921852112}],"concepts":[{"id":"https://openalex.org/C163339463","wikidata":"https://www.wikidata.org/wiki/Q484598","display_name":"CAPTCHA","level":2,"score":0.9660429358482361},{"id":"https://openalex.org/C577917","wikidata":"https://www.wikidata.org/wiki/Q189223","display_name":"Turing test","level":2,"score":0.885719358921051},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.7693013548851013},{"id":"https://openalex.org/C86844869","wikidata":"https://www.wikidata.org/wiki/Q2798820","display_name":"Hacker","level":2,"score":0.7027207612991333},{"id":"https://openalex.org/C9870796","wikidata":"https://www.wikidata.org/wiki/Q490481","display_name":"Turing","level":2,"score":0.5559195876121521},{"id":"https://openalex.org/C170130773","wikidata":"https://www.wikidata.org/wiki/Q216378","display_name":"Usability","level":2,"score":0.5360717177391052},{"id":"https://openalex.org/C136764020","wikidata":"https://www.wikidata.org/wiki/Q466","display_name":"World Wide Web","level":1,"score":0.5228163003921509},{"id":"https://openalex.org/C9652623","wikidata":"https://www.wikidata.org/wiki/Q190109","display_name":"Field (mathematics)","level":2,"score":0.49208277463912964},{"id":"https://openalex.org/C2777267654","wikidata":"https://www.wikidata.org/wiki/Q3519023","display_name":"Test (biology)","level":2,"score":0.4400450587272644},{"id":"https://openalex.org/C38652104","wikidata":"https://www.wikidata.org/wiki/Q3510521","display_name":"Computer security","level":1,"score":0.4292508661746979},{"id":"https://openalex.org/C35578498","wikidata":"https://www.wikidata.org/wiki/Q193424","display_name":"Web service","level":2,"score":0.4116551876068115},{"id":"https://openalex.org/C107457646","wikidata":"https://www.wikidata.org/wiki/Q207434","display_name":"Human\u2013computer interaction","level":1,"score":0.2675410211086273},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.24654647707939148},{"id":"https://openalex.org/C199360897","wikidata":"https://www.wikidata.org/wiki/Q9143","display_name":"Programming language","level":1,"score":0.08530893921852112},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.0},{"id":"https://openalex.org/C151730666","wikidata":"https://www.wikidata.org/wiki/Q7205","display_name":"Paleontology","level":1,"score":0.0},{"id":"https://openalex.org/C202444582","wikidata":"https://www.wikidata.org/wiki/Q837863","display_name":"Pure mathematics","level":1,"score":0.0},{"id":"https://openalex.org/C86803240","wikidata":"https://www.wikidata.org/wiki/Q420","display_name":"Biology","level":0,"score":0.0}],"mesh":[],"locations_count":1,"locations":[{"id":"doi:10.1016/b978-0-12-385510-7.00003-5","is_oa":false,"landing_page_url":"https://doi.org/10.1016/b978-0-12-385510-7.00003-5","pdf_url":null,"source":{"id":"https://openalex.org/S183285281","display_name":"Advances in computers","issn_l":"0065-2458","issn":["0065-2458"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320990","host_organization_name":"Elsevier BV","host_organization_lineage":["https://openalex.org/P4310320990"],"host_organization_lineage_names":["Elsevier BV"],"type":"book series"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Advances in Computers","raw_type":"book-chapter"}],"best_oa_location":null,"sustainable_development_goals":[],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":169,"referenced_works":["https://openalex.org/W18310804","https://openalex.org/W114267068","https://openalex.org/W1482696268","https://openalex.org/W1484545732","https://openalex.org/W1485610138","https://openalex.org/W1535343243","https://openalex.org/W1537809898","https://openalex.org/W1550302713","https://openalex.org/W1567048812","https://openalex.org/W1583532599","https://openalex.org/W1584565669","https://openalex.org/W1592017725","https://openalex.org/W1603565383","https://openalex.org/W1613836731","https://openalex.org/W1660562555","https://openalex.org/W1726017835","https://openalex.org/W1805165030","https://openalex.org/W1907757315","https://openalex.org/W1934382142","https://openalex.org/W1965636838","https://openalex.org/W1969420741","https://openalex.org/W1969670714","https://openalex.org/W1970243262","https://openalex.org/W1974008446","https://openalex.org/W1990178240","https://openalex.org/W1992837034","https://openalex.org/W1998176547","https://openalex.org/W2001771035","https://openalex.org/W2003453784","https://openalex.org/W2015824828","https://openalex.org/W2022710553","https://openalex.org/W2023103153","https://openalex.org/W2029891985","https://openalex.org/W2030497396","https://openalex.org/W2031859714","https://openalex.org/W2033148163","https://openalex.org/W2034248029","https://openalex.org/W2045782640","https://openalex.org/W2047535635","https://openalex.org/W2060853104","https://openalex.org/W2061777480","https://openalex.org/W2067655915","https://openalex.org/W2069902204","https://openalex.org/W2072410439","https://openalex.org/W2073458816","https://openalex.org/W2075785508","https://openalex.org/W2082839416","https://openalex.org/W2084062832","https://openalex.org/W2086464669","https://openalex.org/W2092944485","https://openalex.org/W2093703852","https://openalex.org/W2096153383","https://openalex.org/W2099256741","https://openalex.org/W2100172693","https://openalex.org/W2102698388","https://openalex.org/W2105598383","https://openalex.org/W2107612984","https://openalex.org/W2108724351","https://openalex.org/W2112981015","https://openalex.org/W2113321599","https://openalex.org/W2115171321","https://openalex.org/W2115601549","https://openalex.org/W2116241551","https://openalex.org/W2116406464","https://openalex.org/W2116705992","https://openalex.org/W2118757751","https://openalex.org/W2125561172","https://openalex.org/W2127385077","https://openalex.org/W2129824148","https://openalex.org/W2133300631","https://openalex.org/W2134909295","https://openalex.org/W2137562222","https://openalex.org/W2139024815","https://openalex.org/W2140257942","https://openalex.org/W2140838239","https://openalex.org/W2141156370","https://openalex.org/W2141282920","https://openalex.org/W2143684471","https://openalex.org/W2143700827","https://openalex.org/W2144409202","https://openalex.org/W2145204224","https://openalex.org/W2145482038","https://openalex.org/W2147019420","https://openalex.org/W2147100356","https://openalex.org/W2152229949","https://openalex.org/W2153601419","https://openalex.org/W2155200289","https://openalex.org/W2156749117","https://openalex.org/W2158928168","https://openalex.org/W2159255787","https://openalex.org/W2161466446","https://openalex.org/W2163390356","https://openalex.org/W2163705281","https://openalex.org/W2167292282","https://openalex.org/W2169214380","https://openalex.org/W2170472066","https://openalex.org/W2171973097","https://openalex.org/W2251410821","https://openalex.org/W2293311870","https://openalex.org/W2293727296","https://openalex.org/W2294526606","https://openalex.org/W2295254414","https://openalex.org/W2295513779","https://openalex.org/W2295754936","https://openalex.org/W2466655566","https://openalex.org/W2476374105","https://openalex.org/W2535058588","https://openalex.org/W2538172118","https://openalex.org/W2544392478","https://openalex.org/W2573956962","https://openalex.org/W2595697910","https://openalex.org/W2597289420","https://openalex.org/W2800648970","https://openalex.org/W3023177273","https://openalex.org/W3150357344","https://openalex.org/W4206109607","https://openalex.org/W4236521339","https://openalex.org/W4243801960","https://openalex.org/W4254515799","https://openalex.org/W6604699679","https://openalex.org/W6628861489","https://openalex.org/W6631886457","https://openalex.org/W6633971801","https://openalex.org/W6638470279","https://openalex.org/W6641832472","https://openalex.org/W6642503327","https://openalex.org/W6642714445","https://openalex.org/W6650179231","https://openalex.org/W6658617526","https://openalex.org/W6659070539","https://openalex.org/W6671357888","https://openalex.org/W6672008901","https://openalex.org/W6673483571","https://openalex.org/W6673840331","https://openalex.org/W6674406320","https://openalex.org/W6674973596","https://openalex.org/W6675510140","https://openalex.org/W6675945248","https://openalex.org/W6676183388","https://openalex.org/W6676293681","https://openalex.org/W6676728134","https://openalex.org/W6676878587","https://openalex.org/W6677551341","https://openalex.org/W6678591372","https://openalex.org/W6679008699","https://openalex.org/W6679706891","https://openalex.org/W6679981236","https://openalex.org/W6680705999","https://openalex.org/W6680811095","https://openalex.org/W6681398885","https://openalex.org/W6681511279","https://openalex.org/W6681687456","https://openalex.org/W6681769880","https://openalex.org/W6682245957","https://openalex.org/W6682764186","https://openalex.org/W6683511782","https://openalex.org/W6684090411","https://openalex.org/W6684847500","https://openalex.org/W6696665504","https://openalex.org/W6696912190","https://openalex.org/W6696941722","https://openalex.org/W6697125189","https://openalex.org/W6697171207","https://openalex.org/W6697412482","https://openalex.org/W6719969877","https://openalex.org/W6728302054","https://openalex.org/W6729394008","https://openalex.org/W6761458585","https://openalex.org/W6825103548"],"related_works":["https://openalex.org/W4312500010","https://openalex.org/W2313567600","https://openalex.org/W2086464669","https://openalex.org/W2965099444","https://openalex.org/W1999034556","https://openalex.org/W1998496804","https://openalex.org/W1991242267","https://openalex.org/W2910114670","https://openalex.org/W3144744384","https://openalex.org/W33990236"],"abstract_inverted_index":null,"counts_by_year":[{"year":2025,"cited_by_count":2},{"year":2024,"cited_by_count":2},{"year":2022,"cited_by_count":4},{"year":2021,"cited_by_count":1},{"year":2020,"cited_by_count":8},{"year":2019,"cited_by_count":1},{"year":2017,"cited_by_count":3},{"year":2016,"cited_by_count":1},{"year":2015,"cited_by_count":4},{"year":2014,"cited_by_count":4},{"year":2013,"cited_by_count":1},{"year":2012,"cited_by_count":1}],"updated_date":"2026-07-22T07:51:19.307946","created_date":"2016-06-24T00:00:00"}