From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34780C468C6 for ; Thu, 19 Jul 2018 14:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A840B2084C for ; Thu, 19 Jul 2018 14:21:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=thunk.org header.i=@thunk.org header.b="hSRqRsze" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A840B2084C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731676AbeGSPFR (ORCPT ); Thu, 19 Jul 2018 11:05:17 -0400 Received: from imap.thunk.org ([74.207.234.97]:33674 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727575AbeGSPFQ (ORCPT ); Thu, 19 Jul 2018 11:05:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=aO9pp5UDhzp+MnmYgQF+FElc/xFcpj+54fndI7BnxDU=; b=hSRqRsze6T3UnLZGOKgGZquv4V Gw6nDQ0RphS8WLVJ6EJn/MbcsmuwreIewzMI1NsB+fGtCLvwGDxA5J9pTWpNjEf5XEFHFurLF+a+2 xqoPUWgevGCWrXcDWp8Dj/wMCQFMYmbdiY5ZOTClN0S8nX80fWojQ0kVQdG4tn6egMcA=; Received: from root (helo=callcc.thunk.org) by imap.thunk.org with local-esmtp (Exim 4.89) (envelope-from ) id 1fg9oV-0005LD-MJ; Thu, 19 Jul 2018 14:21:51 +0000 Received: by callcc.thunk.org (Postfix, from userid 15806) id B5CBA7A6413; Thu, 19 Jul 2018 10:21:48 -0400 (EDT) Date: Thu, 19 Jul 2018 10:21:48 -0400 From: "Theodore Y. Ts'o" To: Sandy Harris Cc: Linux Crypto Mailing List , Linux Kernel Developers List , labbott@redhat.com Subject: Re: [PATCH] random: addu a config option to trust the CPU's hwrng Message-ID: <20180719142148.GH30706@thunk.org> Mail-Followup-To: "Theodore Y. Ts'o" , Sandy Harris , Linux Crypto Mailing List , Linux Kernel Developers List , labbott@redhat.com References: <20180718014344.1309-1-tytso@mit.edu> <20180718015154.GE3489@thunk.org> <20180718173621.GC30706@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 18, 2018 at 04:22:35PM -0400, Sandy Harris wrote: > > Yes & one of those can also solve any difficulty with random(4) at > startup. Another alternative, perhaps easier on some systems, is > Denker's Turbid trng: > https://www.av8n.com/turbid/paper/turbid.htm In the link above I saw breadboards with resistors plugged in, alligator clips to TRG plugs, shield boxes with aluminum foil, and doing calibrations using voltmeters. While that induced a pleasant flashback to my junior high days when I experimented with electronics, I'm not entirely sure most sysadmins would call that "easy". :-) - Ted