{"id":10556,"date":"2023-04-11T12:34:19","date_gmt":"2023-04-11T12:34:19","guid":{"rendered":"https:\/\/www.bitnovo.com\/blog\/?p=10556"},"modified":"2025-09-10T15:22:57","modified_gmt":"2025-09-10T15:22:57","slug":"what-is-a-sybil-attack-guide-for-dummies","status":"publish","type":"post","link":"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies","title":{"rendered":"What is a Sybil attack? Guide for Dummies"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 counter-hierarchy ez-toc-counter ez-toc-transparent ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Alternar tabla de contenidos\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #ffffff;color:#ffffff\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #ffffff;color:#ffffff\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#what_is_a_sybil_attack\" >What is a Sybil attack?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#how_does_a_sybil_attack_work\" >How does a Sybil attack work?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#how_can_it_be_prevented\" >How can it be prevented?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#1_grant_different_powers_to_different_members\" >1. Grant different powers to different members<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#2_generate_costs_to_create_an_identity\" >2. Generate costs to create an identity<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#3_limit_the_number_of_identities_per_node\" >3. Limit the number of identities per node.<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#4_validate_identities_before_joining_the_network\" >4. Validate identities before joining the network.<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-sybil-attack-guide-for-dummies\/#5_apply_a_set_of_rules_for_the_generation_of_new_blocks\" >5. Apply a set of rules for the generation of new blocks.<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Tiempo de lectura:<\/span> <span class=\"rt-time\"> 3<\/span> <span class=\"rt-label rt-postfix\">minutos<\/span><\/span><p class=\"p1\"><span class=\"s1\">One of the greatest concerns in the technological era in which we live<strong>\u00a0is the malicious use of bots or artificial intelligences.\u00a0<\/strong><\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">Consequently, contrary to what we would think,\u00a0<strong>blockchain networks<\/strong>\u00a0(secure environments)\u00a0<strong>can also be affected<\/strong>\u00a0either by Byzantine failures, DDoS attacks (denial of service attack), among others.\u00a0<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">Today we will discuss one particular attack that can threaten the security of any system and is a constant concern in the crypto ecosystem.<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">As it could not be otherwise, let\u2019s start by knowing what Sybil\u2019s attacks (Sybil Attack) are.\u00a0\u00a0<\/span><\/p>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<h2><span class=\"ez-toc-section\" id=\"what_is_a_sybil_attack\"><\/span>What is a Sybil attack?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<div class=\"is-divider divider clearfix\"><\/div>\n<p class=\"p1\"><span class=\"s1\">A Sybil attack\u00a0<strong>is an attack that threatens the security of a system<\/strong>, since it is a malicious actor that attempts to\u00a0<strong>completely control a network, using multiple fake identities, nodes or pcs.\u00a0<\/strong><\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">This type of attack usually occurs in\u00a0<strong>p2p (peer to peer) networks<\/strong>, that is, networks that work through a series of nodes or computers that work in the same way as each other.\u00a0<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">One way in which I could exemplify these attacks is with\u00a0<strong>presidential voting.<\/strong><\/span><\/p>\n<p><b>Example<\/b><\/p>\n<p>Let\u2019s imagine that we have two candidates and one of them is more popular and is expected to win.<\/p>\n<p class=\"p1\"><span class=\"s1\">However, several of the people who have access to the ballots, take the voters\u2019 data, get rid of these votes and introduce new ballots with votes for the less popular candidate.\u00a0<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">Thus, in this process,\u00a0<strong>votes are being falsified and, therefore, the identities of voters in order to have a complete administration of the voting system.\u00a0<\/strong><\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">In a common scenario, we could go so far as to identify people who monitor voting or who violated cyber rules.<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">However, in a decentralized universe where anonymity prevails,\u00a0<strong>it is really difficult<\/strong>\u00a0to conclude that identities come from a single person.<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">As a curious fact, the name \u201cSybil\u201d comes from the 1973 book \u201cSybil\u201d by journalist Flora Theta Schreiber.\u00a0<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">This book studies the case of Shirley Ardell Manson, whose pseudonym is Sybil Dorsett, a woman diagnosed with dissociative identity disorder (DID), formerly called \u201cmultiple personality disorder.\u201d\u00a0<\/span><\/p>\n<p class=\"p1\"><span class=\"s1\">In 2002, Brian Zil, a Microsoft computer scientist, suggested the name for a paper by John R. Douceur, a researcher on the subject at Microsoft.\u00a0<\/span><\/p>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<h2><span class=\"ez-toc-section\" id=\"how_does_a_sybil_attack_work\"><\/span>How does a Sybil attack work?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<div class=\"is-divider divider clearfix\"><\/div>\n<p>As mentioned before, a peer to peer network works by means of nodes. Each node has a function within the system.<\/p>\n<p><strong>A successful Sybil attack on a blockchain is one in which enough identities or nodes are created to influence others.<\/strong><\/p>\n<p>Even complete dominance can be obtained if the fake identities manage to outvote the honest nodes in the network, as in the example of the under-recognized presidential candidate.<\/p>\n<p>Once you achieve system contamination by the large number of identities, you can:<\/p>\n<ul>\n<li>\n<ul>\n<li><strong>Alter routes.<\/strong><\/li>\n<li><strong>Modify stored content.<\/strong><\/li>\n<li><strong>Deny the creation of blocks,\u00a0<\/strong>which prevents the recording and operation of transactions.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>If it manages to reach a large scale where they can control most of the network, a<a href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-a-51-blockchain-attack\/\">\u00a051% attack<\/a>\u00a0can occur.\u00a0<\/strong>In it, the order of transactions can be changed, spending can be doubled or transactions can be reversed.<\/p>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div id=\"image_1881134087\" class=\"img has-hover x md-x lg-x y md-y lg-y\">\n<div class=\"img-inner dark\"><img fetchpriority=\"high\" decoding=\"async\" class=\"attachment-large size-large lazyloaded\" src=\"https:\/\/www.bitnovo.com\/blog\/wp-content\/uploads\/2021\/07\/Que-son-los-ataques-de-Sybil2.jpg\" sizes=\"(max-width: 768px) 100vw, 768px\" srcset=\"https:\/\/www.bitnovo.com\/blog\/wp-content\/uploads\/2021\/07\/Que-son-los-ataques-de-Sybil2.jpg 768w, https:\/\/www.bitnovo.com\/blog\/wp-content\/uploads\/2021\/07\/Que-son-los-ataques-de-Sybil2-300x205.jpg 300w\" alt=\"\u00bfQu\u00e9 es un ataque Sybil? Gu\u00eda para Dummies\" width=\"768\" height=\"526\" data-srcset=\"https:\/\/www.bitnovo.com\/blog\/wp-content\/uploads\/2021\/07\/Que-son-los-ataques-de-Sybil2.jpg 768w, https:\/\/www.bitnovo.com\/blog\/wp-content\/uploads\/2021\/07\/Que-son-los-ataques-de-Sybil2-300x205.jpg 300w\" data-src=\"https:\/\/www.bitnovo.com\/blog\/wp-content\/uploads\/2021\/07\/Que-son-los-ataques-de-Sybil2.jpg\" data-sizes=\"(max-width: 768px) 100vw, 768px\" \/><\/div>\n<\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<h2><span class=\"ez-toc-section\" id=\"how_can_it_be_prevented\"><\/span>How can it be prevented?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<div class=\"is-divider divider clearfix\"><\/div>\n<p>There are five essential ways to reduce the risk of such attacks:<\/p>\n<h3><span class=\"ez-toc-section\" id=\"1_grant_different_powers_to_different_members\"><\/span><b>1. Grant different powers to different members<\/b><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>One solution may be reputation systems, in which there are different levels of power according to the trustworthiness of that person within the network.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"2_generate_costs_to_create_an_identity\"><\/span><b><br \/>\n2. Generate costs to create an identity<\/b><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>A sum of money may be requested so that each person can create an identity.<\/p>\n<p>In this way, it will be more complicated for the attacker to cover the costs to execute his attack.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"3_limit_the_number_of_identities_per_node\"><\/span><b><br \/>\n3. Limit the number of identities per node.<\/b><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>One effective way is to disallow multiple fake identities to operate at the same time from the same IP or device.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"4_validate_identities_before_joining_the_network\"><\/span><b><br \/>\n4. Validate identities before joining the network.<\/b><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>There are two ways to do this:<\/p>\n<p><strong>The direct one,<\/strong>\u00a0in which an established entity is in charge of verifying the new member of the network.<\/p>\n<p>On the other hand,\u00a0<strong>the indirect<\/strong>\u00a0<strong>one<\/strong>, which works as a trust system in which the established entity verifies some members.<\/p>\n<p>Then, who can verify the new members who join after them and so on. This mode assumes that new users are honest.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"5_apply_a_set_of_rules_for_the_generation_of_new_blocks\"><\/span><b><br \/>\n5. Apply a set of rules for the generation of new blocks.<\/b><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>The consensus algorithms of different projects, such as Bitcoin, employ \u201crules\u201d to circumvent these attacks.<\/p>\n<p>One of them may be that each node has the computational power necessary to create a new block.<\/p>\n<p>Therefore, it will be difficult to create several identities without them coming from the same PC, especially taking into account algorithms such as\u00a0<a href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-proof-of-work-the-bitcoin-consensus-protocol\/\">Proof of Work.<\/a><\/p>\n<p>Likewise, through rewards they ensure that miners keep their mining honest.<\/p>\n<p>In this blog we have also talked about\u00a0<a href=\"https:\/\/www.bitnovo.com\/blog\/en\/what-is-proof-of-humanity-poh-the-anti-robot-system\/\">Proof of Humanity<\/a>, a novel solution endorsed by\u00a0<a href=\"https:\/\/www.bitnovo.com\/blog\/en\/who-is-vitalik-buterin\/\">Vitalik Buterin<\/a>\u00a0to prevent Sybil attacks. POH creates the first decentralized registry of humans to address this issue.<\/p>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<div class=\"is-divider divider clearfix\"><\/div>\n<p>Congratulations on making it all the way to the end!<\/p>\n<p>If you want to know more about these topics you can click on the related articles below.<\/p>\n<p>See you next time!<\/p>\n","protected":false},"excerpt":{"rendered":"<p><span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">Tiempo de lectura:<\/span> <span class=\"rt-time\"> 3<\/span> <span class=\"rt-label rt-postfix\">minutos<\/span><\/span>One of the greatest concerns in the technological era in which we live\u00a0is the malicious use of bots or artificial intelligences.\u00a0 Consequently, contrary to what we would think,\u00a0blockchain networks\u00a0(secure environments)\u00a0can also be affected\u00a0either by Byzantine failures, DDoS attacks (denial of service attack), among others.\u00a0 Today we will discuss one particular attack that can threaten the [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":7652,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[165],"tags":[],"class_list":["post-10556","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cryptocurrencies"],"_links":{"self":[{"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/posts\/10556","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/comments?post=10556"}],"version-history":[{"count":2,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/posts\/10556\/revisions"}],"predecessor-version":[{"id":24641,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/posts\/10556\/revisions\/24641"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/media\/7652"}],"wp:attachment":[{"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/media?parent=10556"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/categories?post=10556"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bitnovo.com\/blog\/wp-json\/wp\/v2\/tags?post=10556"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}