{"id":70394,"date":"2026-05-15T16:06:18","date_gmt":"2026-05-15T15:06:18","guid":{"rendered":"https:\/\/ekiwi-blog.de\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/"},"modified":"2026-07-19T12:33:56","modified_gmt":"2026-07-19T11:33:56","slug":"openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus","status":"publish","type":"post","link":"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/","title":{"rendered":"OpenSSL DLLs for Windows: A collection for developers (e.g. Lazarus)"},"content":{"rendered":"<p>When developing Windows applications\u2014for example with Lazarus (Free Pascal)\u2014OpenSSL is often required for encrypted network connections. Because Windows does not include these libraries by default, the appropriate DLL files must be distributed with the application.<\/p>\n<p><!--more--><\/p>\n<p>For my own projects, I have assembled a selection of frequently required OpenSSL files and am making them available for download here.<\/p>\n<hr>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of content<\/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=\"Toggle Table of Content\"><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: #999;color:#999\" 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: #999;color:#999\" 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 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#Package_contents\" >Package contents<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#OpenSSL_3x_64-bit\" >OpenSSL 3.x (64-bit)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#OpenSSL_11x_64-bit\" >OpenSSL 1.1.x (64-bit)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#OpenSSL_11x_32-bit\" >OpenSSL 1.1.x (32-bit)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#Older_OpenSSL_versions_10x\" >Older OpenSSL versions (1.0.x)<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#Usage\" >Usage<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/ekiwi-blog.de\/en\/70394\/openssl-dlls-for-windows-a-collection-for-developers-eg-lazarus\/#Security_note\" >Security note<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Package_contents\"><\/span>Package contents<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The collection contains files from different OpenSSL branches and for different architectures. The required libraries depend on the age of the project, the components used, and the target platform.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"OpenSSL_3x_64-bit\"><\/span>OpenSSL 3.x (64-bit)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>These files are required by many newer 64-bit applications and modern HTTP clients:<\/p>\n<ul>\n<li><b><code>libcrypto-3-x64.dll<\/code><\/b><\/li>\n<li><b><code>libssl-3-x64.dll<\/code><\/b><\/li>\n<li><b><code>libcrypto.dll<\/code><\/b> \u2014 used as a generic fallback name by certain frameworks<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"OpenSSL_11x_64-bit\"><\/span>OpenSSL 1.1.x (64-bit)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>These files are used by 64-bit applications and components that have not yet transitioned to OpenSSL 3.x:<\/p>\n<ul>\n<li><b><code>libcrypto-1_1-x64.dll<\/code><\/b><\/li>\n<li><b><code>libssl-1_1-x64.dll<\/code><\/b><\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"OpenSSL_11x_32-bit\"><\/span>OpenSSL 1.1.x (32-bit)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>These files are required by 32-bit applications, including Lazarus applications compiled for the <code>i386-win32<\/code> target:<\/p>\n<ul>\n<li><b><code>libcrypto-1_1.dll<\/code><\/b><\/li>\n<li><b><code>libssl-1_1.dll<\/code><\/b><\/li>\n<\/ul>\n<p>Both files must be used together and must not be combined with their 64-bit counterparts.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Older_OpenSSL_versions_10x\"><\/span>Older OpenSSL versions (1.0.x)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>These files are frequently required by older projects or network components, including certain versions of Indy or Synapse:<\/p>\n<ul>\n<li><b><code>libeay32.dll<\/code><\/b><\/li>\n<li><b><code>ssleay32.dll<\/code><\/b><\/li>\n<\/ul>\n<p>The number <code>32<\/code> in these filenames is historical and is not always a reliable indication of the actual architecture. If in doubt, verify the architecture before using the files.<\/p>\n<hr>\n<h2><span class=\"ez-toc-section\" id=\"Usage\"><\/span>Usage<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>The safest approach is generally to copy the required DLL pair directly into the directory containing the application executable\u2014that is, next to the <code>.exe<\/code> file. This keeps the application portable and ensures that it uses the exact libraries with which it was tested.<\/p>\n<p>Keep the following points in mind:<\/p>\n<ul>\n<li>A 32-bit application requires 32-bit DLLs.<\/li>\n<li>A 64-bit application requires 64-bit DLLs.<\/li>\n<li><code>libssl<\/code> and <code>libcrypto<\/code> must come from the same OpenSSL package.<\/li>\n<li>Files from different OpenSSL versions must not be mixed.<\/li>\n<li>Renaming newer DLLs to older filenames does not make them compatible.<\/li>\n<li>Avoid placing the DLLs in Windows system directories, as this can cause version and architecture conflicts.<\/li>\n<\/ul>\n<hr>\n<h2><span class=\"ez-toc-section\" id=\"Security_note\"><\/span>Security note<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Public support for OpenSSL 1.1.1 ended in September 2023. It should only be used when required for compatibility and when migration to a currently supported OpenSSL version is not yet possible.<\/p>\n<p>The older <code>ssleay32.dll<\/code> and <code>libeay32.dll<\/code> files date from 2018. They no longer meet current security standards and contain known vulnerabilities. They should only be used to maintain compatibility with existing, preferably isolated, legacy systems.<\/p>\n<p>For new or security-critical applications, use a currently supported OpenSSL release whenever the application and its TLS integration support it.<\/p>\n<p><a href=\"https:\/\/ekiwi-blog.de\/wp-content\/uploads\/2026\/05\/libssl.zip\">Download the DLL files<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>When developing Windows applications\u2014for example with Lazarus (Free Pascal)\u2014OpenSSL is often required for encrypted network connections. Because Windows does not<\/p>\n","protected":false},"author":1,"featured_media":14619,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1555],"tags":[3942,3943,3384,2068],"class_list":["post-70394","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-software-en","tag-development-en","tag-dll-en","tag-lazarus-en","tag-windows-en-2"],"_links":{"self":[{"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/posts\/70394","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/comments?post=70394"}],"version-history":[{"count":0,"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/posts\/70394\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/media\/14619"}],"wp:attachment":[{"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/media?parent=70394"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/categories?post=70394"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ekiwi-blog.de\/en\/wp-json\/wp\/v2\/tags?post=70394"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}