{"id":57,"date":"2008-07-06T14:22:53","date_gmt":"2008-07-06T12:22:53","guid":{"rendered":"http:\/\/bergs.biz\/blog\/?p=57"},"modified":"2015-06-19T09:22:03","modified_gmt":"2015-06-19T07:22:03","slug":"gpg-with-idea-on-the-mac","status":"publish","type":"post","link":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/","title":{"rendered":"GPG with IDEA on the Mac"},"content":{"rendered":"<p>One of the first things I did when I got my new Mac was install Mozilla Thunderbird, the invaluable EnigMail extension, which is a very easy-to-use frontend to GNU Privacy Guard (GPG), and of course GPG itself.<\/p>\n<p>All went very smoothly, and to check whether the installation was fine I tried to opened an encrypted message which I had received some days ago. Unfortunetly GPG couldn&#8217;t decrypt the message. A quick look at EnigMail&#8217;s console window told me that the message was encrypted using <a title=\"International Data Encryption Algorithm\" href=\"http:\/\/en.wikipedia.org\/wiki\/International_Data_Encryption_Algorithm\" target=\"_blank\">IDEA<\/a>, and that the version of GPG I had installed was lacking support of that encryption algorithm.<\/p>\n<p><!--more-->So I downloaded myself the <a title=\"source code of IDEA plugin\" href=\"ftp:\/\/ftp.gnupg.dk\/pub\/contrib-dk\/idea.c.gz \">source<\/a> of the IDEA plugin, which is just a single C source file. A quick search at Google pointed me to <a href=\"http:\/\/macgpg.sourceforge.net\/en\/docs\/howto-install-IDEA.txt.asc\" target=\"_blank\">this<\/a> page on MacPGP, which unfortunately only described how to compile the module into GPG, which is not what I wanted. It&#8217;s also possible to compile IDEA into a dynamically-loadable module (that GPG loads with dlopen). I prefer that method because when a new version of GPG becomes available, I don&#8217;t have to recompile everything, but the new version willl automatically use the dynamic module I compiled erlier.<\/p>\n<p>I couldn&#8217;t find any instructions how to compile the source file into a dynamic module, but I had fragments of the command-line still in my mind. I quickly came up with the following which did the trick for me:<\/p>\n<pre>gcc -dynamic -Wall -O2 -shared -fPIC -c -o idea.o idea.c\r\nlibtool -dynamic -o idea.do -lc idea.o<\/pre>\n<p>To make GPG use that module I changed <code>.gnupg\/gpg.conf<\/code> to include the following option:<\/p>\n<pre>load-extension \/usr\/local\/lib\/gnupg\/idea.do<\/pre>\n<p>I restarted Thunderbird and invoked the console again. As you can see, IDEA support is now present:<\/p>\n<pre>Supported algorithms:\r\nPubkey: RSA, RSA-E, RSA-S, ELG-E, DSA\r\nCipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH\r\nHash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224\r\nCompression: Uncompressed, ZIP, ZLIB, BZIP2<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>How to compile IDEA as a dynamically-loadable module for GPG on a Mac.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,27],"tags":[29,28,31],"class_list":["post-57","post","type-post","status-publish","format-standard","hentry","category-computers","category-mac-computers","tag-encryption","tag-gpg","tag-security"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>GPG with IDEA on the Mac - Ralf&#039;s Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"GPG with IDEA on the Mac - Ralf&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"How to compile IDEA as a dynamically-loadable module for GPG on a Mac.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/\" \/>\n<meta property=\"og:site_name\" content=\"Ralf&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2008-07-06T12:22:53+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2015-06-19T07:22:03+00:00\" \/>\n<meta name=\"author\" content=\"Ralf Bergs\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@ralfbergs\" \/>\n<meta name=\"twitter:site\" content=\"@ralfbergs\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Ralf Bergs\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/\"},\"author\":{\"name\":\"Ralf Bergs\",\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/#\\\/schema\\\/person\\\/354e37390b493c875f972bd313d29201\"},\"headline\":\"GPG with IDEA on the Mac\",\"datePublished\":\"2008-07-06T12:22:53+00:00\",\"dateModified\":\"2015-06-19T07:22:03+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/\"},\"wordCount\":275,\"commentCount\":4,\"publisher\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/#\\\/schema\\\/person\\\/354e37390b493c875f972bd313d29201\"},\"keywords\":[\"encryption\",\"gpg\",\"security\"],\"articleSection\":[\"Computers\",\"Mac\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/\",\"url\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/\",\"name\":\"GPG with IDEA on the Mac - Ralf&#039;s Blog\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/#website\"},\"datePublished\":\"2008-07-06T12:22:53+00:00\",\"dateModified\":\"2015-06-19T07:22:03+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/2008\\\/07\\\/06\\\/gpg-with-idea-on-the-mac\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"GPG with IDEA on the Mac\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/#website\",\"url\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/\",\"name\":\"Ralf's Blog\",\"description\":\"Just another WordPress weblog\",\"publisher\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/#\\\/schema\\\/person\\\/354e37390b493c875f972bd313d29201\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":[\"Person\",\"Organization\"],\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/#\\\/schema\\\/person\\\/354e37390b493c875f972bd313d29201\",\"name\":\"Ralf Bergs\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/Ralf-Tower-2026-1024x1024.jpg\",\"url\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/Ralf-Tower-2026-1024x1024.jpg\",\"contentUrl\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/Ralf-Tower-2026-1024x1024.jpg\",\"width\":1024,\"height\":1024,\"caption\":\"Ralf Bergs\"},\"logo\":{\"@id\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/Ralf-Tower-2026-1024x1024.jpg\"},\"description\":\"Geek, computer guy, licensed and certified electrical and computer engineer, husband, best daddy.\",\"sameAs\":[\"https:\\\/\\\/bergs.biz\\\/\",\"https:\\\/\\\/linkedin.com\\\/in\\\/ralfbergs\\\/\",\"https:\\\/\\\/x.com\\\/ralfbergs\"],\"url\":\"https:\\\/\\\/bergs.biz\\\/blog\\\/author\\\/rabe\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"GPG with IDEA on the Mac - Ralf&#039;s Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/","og_locale":"en_US","og_type":"article","og_title":"GPG with IDEA on the Mac - Ralf&#039;s Blog","og_description":"How to compile IDEA as a dynamically-loadable module for GPG on a Mac.","og_url":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/","og_site_name":"Ralf&#039;s Blog","article_published_time":"2008-07-06T12:22:53+00:00","article_modified_time":"2015-06-19T07:22:03+00:00","author":"Ralf Bergs","twitter_card":"summary_large_image","twitter_creator":"@ralfbergs","twitter_site":"@ralfbergs","twitter_misc":{"Written by":"Ralf Bergs","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/#article","isPartOf":{"@id":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/"},"author":{"name":"Ralf Bergs","@id":"https:\/\/bergs.biz\/blog\/#\/schema\/person\/354e37390b493c875f972bd313d29201"},"headline":"GPG with IDEA on the Mac","datePublished":"2008-07-06T12:22:53+00:00","dateModified":"2015-06-19T07:22:03+00:00","mainEntityOfPage":{"@id":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/"},"wordCount":275,"commentCount":4,"publisher":{"@id":"https:\/\/bergs.biz\/blog\/#\/schema\/person\/354e37390b493c875f972bd313d29201"},"keywords":["encryption","gpg","security"],"articleSection":["Computers","Mac"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/","url":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/","name":"GPG with IDEA on the Mac - Ralf&#039;s Blog","isPartOf":{"@id":"https:\/\/bergs.biz\/blog\/#website"},"datePublished":"2008-07-06T12:22:53+00:00","dateModified":"2015-06-19T07:22:03+00:00","breadcrumb":{"@id":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/bergs.biz\/blog\/2008\/07\/06\/gpg-with-idea-on-the-mac\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/bergs.biz\/blog\/"},{"@type":"ListItem","position":2,"name":"GPG with IDEA on the Mac"}]},{"@type":"WebSite","@id":"https:\/\/bergs.biz\/blog\/#website","url":"https:\/\/bergs.biz\/blog\/","name":"Ralf's Blog","description":"Just another WordPress weblog","publisher":{"@id":"https:\/\/bergs.biz\/blog\/#\/schema\/person\/354e37390b493c875f972bd313d29201"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/bergs.biz\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":["Person","Organization"],"@id":"https:\/\/bergs.biz\/blog\/#\/schema\/person\/354e37390b493c875f972bd313d29201","name":"Ralf Bergs","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/bergs.biz\/blog\/wp-content\/uploads\/2026\/04\/Ralf-Tower-2026-1024x1024.jpg","url":"https:\/\/bergs.biz\/blog\/wp-content\/uploads\/2026\/04\/Ralf-Tower-2026-1024x1024.jpg","contentUrl":"https:\/\/bergs.biz\/blog\/wp-content\/uploads\/2026\/04\/Ralf-Tower-2026-1024x1024.jpg","width":1024,"height":1024,"caption":"Ralf Bergs"},"logo":{"@id":"https:\/\/bergs.biz\/blog\/wp-content\/uploads\/2026\/04\/Ralf-Tower-2026-1024x1024.jpg"},"description":"Geek, computer guy, licensed and certified electrical and computer engineer, husband, best daddy.","sameAs":["https:\/\/bergs.biz\/","https:\/\/linkedin.com\/in\/ralfbergs\/","https:\/\/x.com\/ralfbergs"],"url":"https:\/\/bergs.biz\/blog\/author\/rabe\/"}]}},"_links":{"self":[{"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/posts\/57","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/comments?post=57"}],"version-history":[{"count":1,"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/posts\/57\/revisions"}],"predecessor-version":[{"id":873,"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/posts\/57\/revisions\/873"}],"wp:attachment":[{"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/media?parent=57"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/categories?post=57"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bergs.biz\/blog\/wp-json\/wp\/v2\/tags?post=57"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}