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X-Original-To: cryptography@metzdowd.com Date: Mon, 09 Sep 2013 13:42:36 +1000 From: "James A. Donald" <jamesd@echeque.com> To: cryptography@metzdowd.com In-Reply-To: <20130908211541.557a7c5a@jabberwock.cb.piermont.com> Reply-To: jamesd@echeque.com Errors-To: cryptography-bounces+crypto.discuss=bloom-picayune.mit.edu@metzdowd.com This is a multi-part message in MIME format. --===============0286895679079601675== Content-Type: multipart/alternative; boundary="------------000004020107020100090706" This is a multi-part message in MIME format. --------------000004020107020100090706 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2013-09-09 11:15 AM, Perry E. Metzger wrote: > Lenstra, Heninger and others have both shown mass breaks of keys based > on random number generator flaws in the field. Random number > generators have been the source of a huge number of breaks over time. > > Perhaps you don't see the big worry, but real world experience says > it is something everyone else should worry about anyway. Real world experience is that there is nothing to worry about /if you do it right/. And that it is frequently not done right. When you screw up AES or such, your test vectors fail, your unit test fails, so you fix it, whereas if you screw up entropy, everything appears to work fine. It is hard, perhaps impossible, to have test suite that makes sure that your entropy collection works. One can, however, have a test suite that ascertains that on any two runs of the program, most items collected for entropy are different except for those that are expected to be the same, and that on any run, any item collected for entropy does make a difference. Does your unit test check your entropy collection? --------------000004020107020100090706 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit <html> <head> <meta content="text/html; charset=UTF-8" http-equiv="Content-Type"> </head> <body bgcolor="#FFFFFF" text="#000000"> <div class="moz-cite-prefix">On 2013-09-09 11:15 AM, Perry E. Metzger wrote:<br> </div> <blockquote cite="mid:20130908211541.557a7c5a@jabberwock.cb.piermont.com" type="cite"> <pre wrap="">Lenstra, Heninger and others have both shown mass breaks of keys based on random number generator flaws in the field. Random number generators have been the source of a huge number of breaks over time. Perhaps you don't see the big worry, but real world experience says it is something everyone else should worry about anyway.</pre> </blockquote> <br> Real world experience is that there is nothing to worry about <i>if you do it right</i>. And that it is frequently not done right.<br> <br> When you screw up AES or such, your test vectors fail, your unit test fails, so you fix it, whereas if you screw up entropy, everything appears to work fine.<br> <br> It is hard, perhaps impossible, to have test suite that makes sure that your entropy collection works.<br> <br> One can, however, have a test suite that ascertains that on any two runs of the program, most items collected for entropy are different except for those that are expected to be the same, and that on any run, any item collected for entropy does make a difference.<br> <br> Does your unit test check your entropy collection?<br> <br> </body> </html> --------------000004020107020100090706-- --===============0286895679079601675== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ The cryptography mailing list cryptography@metzdowd.com http://www.metzdowd.com/mailman/listinfo/cryptography --===============0286895679079601675==--
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