<div dir="auto">With that said, if performance is an issue, you might want to look into using SHA512 instead due to optimizations on 64bit platforms.</div><div class="gmail_extra"><br><div class="gmail_quote">On Mar 15, 2017 15:16, "Alex Gaynor" <<a href="mailto:alex.gaynor@gmail.com">alex.gaynor@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">It's also worth noting that the correct time to switch is not when something is broken, it's well before then.<div><br></div><div>Alex</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Mar 15, 2017 at 5:14 PM, Paul Kehrer <span dir="ltr"><<a href="mailto:paul.l.kehrer@gmail.com" target="_blank">paul.l.kehrer@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div id="m_3859927787729804502m_-3568911810663304059bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">Echoing Alex's comments, SHA1's problems do not affect HMAC constructions so there's no current security issue. That said, optics in cryptography can be important (as you're seeing with your user requests now). You will save yourself a great deal of low grade noise in the future by simply switching now.</div><div><div class="m_3859927787729804502h5"> <div id="m_3859927787729804502m_-3568911810663304059bloop_sign_1489612267227323136" class="m_3859927787729804502m_-3568911810663304059bloop_sign"><br></div><p class="m_3859927787729804502m_-3568911810663304059airmail_on">On March 15, 2017 at 1:53:24 PM, Alex Gaynor (<a href="mailto:alex.gaynor@gmail.com" target="_blank">alex.gaynor@gmail.com</a>) wrote:</p> <blockquote type="cite" class="m_3859927787729804502m_-3568911810663304059clean_bq"><span><div><div></div><div>
<div dir="ltr">Hi David,
<div><br></div>
<div>You're correct that HMAC's security is still fine when used
with SHA-1, HMAC-MD5 is even secure believe it or not.</div>
<div><br></div>
<div>That said, I'd generally recommend people migrate to
HMAC-SHA-256 anyways, to make analyzing their software
easier.</div>
<div><br></div>
<div>Alex</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Mar 15, 2017 at 1:48 PM, David
Lord <span dir="ltr"><<a href="mailto:davidism@gmail.com" target="_blank">davidism@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div>Hello cryptography,<br></div>
<div><br>
Over at the Flask repos, we've had a number of requests to use
SHA-256 instead of SHA-1 in a couple places.<br>
Werkzeug defaults to SHA-1 as part of PBKDF2 to generate password
hashes.<br></div>
ItsDangerous defaults to SHA-1 as part of HMAC signatures.<br>
<br></div>
After some discussion I concluded that as used in those two
methods, SHA-1's collision issues were not relevant.<br></div>
However, I'd like to get a second opinion from the cryptography
experts.<br>
<br></div>
I can change the default to SHA-256, but if it's not actually
making things more secure then that's just increasing time and
space for no reason.<br>
<br></div>
Thanks,<br></div>
David<br></div>
<br>
______________________________<wbr>_________________<br>
Cryptography-dev mailing list<br>
<a href="mailto:Cryptography-dev@python.org" target="_blank">Cryptography-dev@python.org</a><br>
<a href="https://mail.python.org/mailman/listinfo/cryptography-dev" rel="noreferrer" target="_blank">https://mail.python.org/mailma<wbr>n/listinfo/cryptography-dev</a><br>
<br></blockquote>
</div>
<br>
<br clear="all">
<div><br></div>
--<br>
<div class="m_3859927787729804502m_-3568911810663304059gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">"I disapprove of what you say, but I will defend to
the death your right to say it." -- Evelyn Beatrice Hall
(summarizing Voltaire)<br>
"The people's good is the highest law." -- Cicero</div>
<div dir="ltr">GPG Key fingerprint: D1B3 ADC0 E023 8CA6<br>
<div><br></div>
</div>
</div>
</div>
</div>
</div>
______________________________<wbr>_________________
<br>Cryptography-dev mailing list
<br><a href="mailto:Cryptography-dev@python.org" target="_blank">Cryptography-dev@python.org</a>
<br><a href="https://mail.python.org/mailman/listinfo/cryptography-dev" target="_blank">https://mail.python.org/mailma<wbr>n/listinfo/cryptography-dev</a>
<br></div></div></span></blockquote></div></div></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="m_3859927787729804502gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr">"I disapprove of what you say, but I will defend to the death your right to say it." -- Evelyn Beatrice Hall (summarizing Voltaire)<br>"The people's good is the highest law." -- Cicero</div><div dir="ltr">GPG Key fingerprint: D1B3 ADC0 E023 8CA6<br><div><br></div></div></div></div></div>
</div>
<br>______________________________<wbr>_________________<br>
Cryptography-dev mailing list<br>
<a href="mailto:Cryptography-dev@python.org">Cryptography-dev@python.org</a><br>
<a href="https://mail.python.org/mailman/listinfo/cryptography-dev" rel="noreferrer" target="_blank">https://mail.python.org/<wbr>mailman/listinfo/cryptography-<wbr>dev</a><br>
<br></blockquote></div></div>