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Dr Stevens has more up to date cost estimates: <a href="https://sites.google.com/site/itstheshappening/" class="">https://sites.google.com/site/itstheshappening/</a>
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<div class="">"<span class="">Concretely, we estimate the SHA-1 collision cost today (i.e., Fall 2015) between 75K$ and 120K$ renting Amazon EC2 cloud computing over a few months.</span><span style="color: rgb(40, 55, 105); font-family: 'Lucida Grande', 'Lucida Sans Unicode', Arial, sans-serif; font-size: 13.3333px; orphans: 2; widows: 2; background-color: rgb(255, 255, 255);" class="">"</span></div>
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<div class="">Cordialement,</div>
<div class="">Erwann Abalea</div>
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<blockquote type="cite" class="">
<div class="">Le 16 déc. 2016 à 15:22, Gervase Markham via Public <<a href="mailto:public@cabforum.org" class="">public@cabforum.org</a>> a écrit :</div>
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<div class="">On 13/12/16 21:40, Ryan Sleevi via Public wrote:<br class="">
<blockquote type="cite" class="">I understand the desire to remove SHA-1 before it has actually shown<br class="">
true weakness.<br class="">
</blockquote>
<br class="">
<a href="https://www.schneier.com/blog/archives/2012/10/when_will_we_se.html" class="">https://www.schneier.com/blog/archives/2012/10/when_will_we_se.html</a> :<br class="">
<br class="">
"The cost of the attack will be approximately:<br class="">
<br class="">
2^13 * 28.4 = 221.4 ~ $2.77M in 2012<br class="">
<br class="">
2^11 * 28.4 = 219.4 ~ $700K by 2015<br class="">
<br class="">
2^9 * 28.4 = 217.4 ~ $173K by 2018<br class="">
<br class="">
2^7 * 28.4 = 215.4 ~ $43K by 2021<br class="">
<br class="">
A collision attack is therefore well within the range of what an<br class="">
organized crime syndicate can practically budget by 2018, and a<br class="">
university research project by 2021.<br class="">
<br class="">
Since this argument only takes into account commodity hardware and not<br class="">
instruction set improvements (e.g., ARM 8 specifies a SHA-1<br class="">
instruction), other commodity computing devices with even greater<br class="">
processing power (e.g., GPUs), and custom hardware, the need to<br class="">
transition from SHA-1 for collision resistance functions is probably<br class="">
more urgent than this back-of-the-envelope analysis suggests."<br class="">
<br class="">
If I were going to calculate a SHA-1 collision, the certificate of a<br class="">
machine handling tens or hundreds of thousands of credit cards a day<br class="">
would be a reasonably obvious target, ISTM.<br class="">
<br class="">
Gerv<br class="">
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