{"id":3013,"date":"2013-09-29T09:18:51","date_gmt":"2013-09-29T09:18:51","guid":{"rendered":"http:\/\/really.zonky.org\/?p=3013"},"modified":"2013-09-29T09:19:56","modified_gmt":"2013-09-29T09:19:56","slug":"linux-devurandom-devrandom","status":"publish","type":"post","link":"https:\/\/really.zonky.org\/?p=3013","title":{"rendered":"Linux: \/dev\/urandom \u2260 \/dev\/random"},"content":{"rendered":"<p>As some people know, the Linux device for generating random numbers (<em>\/dev\/random<\/em>) blocks when there isn&#8217;t sufficient entropy to safely generate random numbers. But people will still persist on advising using\u00a0<em>\/dev\/urandom<\/em> as an alternative :-<\/p>\n<p style=\"padding-left: 30px;\">&#8220;To sum up, under both Linux and FreeBSD, you should use\u00a0<code>\/dev\/urandom<\/code>, not\u00a0<code>\/dev\/random<\/code>.&#8221;<\/p>\n<p style=\"padding-left: 30px;\">&#8220;Just go ahead and use \/dev\/urandom as is&#8221;<\/p>\n<p style=\"padding-left: 30px;\">&#8220;Oracle wants us to move \/dev\/random and link \/dev\/urandom&#8221;<\/p>\n<p style=\"padding-left: 30px;\">&#8220;You can remove \/dev\/random and link that to \/dev\/urandom to help prevent blocking&#8221;<\/p>\n<p>Now it is true that\u00a0<em>\/dev\/urandom<\/em> is usually good enough, but to advise people to use\u00a0<em>\/dev\/urandom<\/em> without considering whether it is sufficient or not is irresponsible. True random numbers can be very important for cryptography, and without knowing it, we use cryptography every day; such as when we browse the web, make <em>ssh<\/em> connections, check PGP keys, etc. Using a weak random number generator can weaken the cryptographic process fatally.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>As some people know, the Linux device for generating random numbers (\/dev\/random) blocks when there isn&#8217;t sufficient entropy to safely generate random numbers. But people will still persist on advising using\u00a0\/dev\/urandom as an alternative :- &#8220;To sum up, under both Linux and FreeBSD, you should use\u00a0\/dev\/urandom, not\u00a0\/dev\/random.&#8221; &#8220;Just go ahead and use \/dev\/urandom as is&#8221; <a href='https:\/\/really.zonky.org\/?p=3013' class='excerpt-more'>[&#8230;]<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"_share_on_mastodon":"0"},"categories":[4,209,489],"tags":[1018,1125,43,1126],"class_list":["post-3013","post","type-post","status-publish","format-standard","hentry","category-it","category-linux-it","category-security","tag-devrandom","tag-cryptography","tag-linux","tag-oracle","category-4-id","category-209-id","category-489-id","post-seq-1","post-parity-odd","meta-position-corners","fix"],"share_on_mastodon":{"url":"","error":""},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p1f2KI-MB","_links":{"self":[{"href":"https:\/\/really.zonky.org\/index.php?rest_route=\/wp\/v2\/posts\/3013","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/really.zonky.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/really.zonky.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/really.zonky.org\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/really.zonky.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3013"}],"version-history":[{"count":2,"href":"https:\/\/really.zonky.org\/index.php?rest_route=\/wp\/v2\/posts\/3013\/revisions"}],"predecessor-version":[{"id":3044,"href":"https:\/\/really.zonky.org\/index.php?rest_route=\/wp\/v2\/posts\/3013\/revisions\/3044"}],"wp:attachment":[{"href":"https:\/\/really.zonky.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3013"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/really.zonky.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3013"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/really.zonky.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3013"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}