SSL-Certificates with SHA256 signature

Hanno's Blog

Monday, February 1. 2010

SSL-Certificates with SHA256 signature


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Weblog: topsy.com
Tracked: Feb 06, 01:42

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Thanks for testing this. I wondered about the same since I had the same problem. I suspect that this > then sha1 incompatibility is just something that gets carried on inside some long untouched config files or man pages for http daemons.

Your site works also with Links 2.2 and Chromium 5.0.308.0 (37385).

I wonder, why not use sha384 or sha512? Did you think of testing those as well?
#1 Pavel (Homepage) on 2010-02-02 03:50 (Reply)
Fuck the CA mafia, everyone should use monkeysphere-style web of trust for HTTPS.
#2 Anonymous on 2010-02-02 04:41 (Reply)
could you please make a wiki on it (sha256 instead of sha1),
like : http://fr.gentoo-wiki.com/wiki/Apache2/Certificats_SSL
see you
Loux
#3 Loux on 2010-02-02 07:54 (Reply)
To reproduce a potential problem:

1) Visit the page with Mozilla Firefox 3.6, granting your browser a temporary security exception
2) Click on the lock in the bottom right corner of the browser window
3) Click "View certificate"

Result: there is no word "SHA256" displayed in the default tab of the certificate window.

4) Click on the "CA root cert" link, view the certficate.

Result: again, there is no word "SHA256" in the default tab. One can only compare MD5 and SHA-1 fingerprints with values obtained, say, from you by phone. I don't know if this is good enough.
#4 Alexander E. Patrakov (Homepage) on 2010-02-02 11:53 (Reply)
As I said, hash functions are used at different places in SSL. The one you mention, the fingerprint, is unrelated to the signing algorithm, so there's no problem (although it might be worth working on that as well).
#4.1 Hanno (Homepage) on 2010-02-02 11:56 (Reply)
Both SHA256 and SHA512 seem to work with Firefox 1.0 and Konqueror 4.0.3.
#5 Anonymous on 2010-02-02 14:11 (Reply)
I am running Windows 2003 SP2 bought at the same day it was released and have no problem (off course, the Service Pack was applied latter...). Don't know if any of the Service Packs fixed the issue.
Both SHA256 and SHA512 worked.
#6 Vinícius G. A. de Oliveira on 2010-02-04 23:58 (Reply)
When I browse to your sha512 testcase (using google chrome on osx 10.6.2) the certificate info reports "SHA-1 with RSA Encryption", instead of the expected sha512.
Maybe there's a mistake in your web server config?

Btw in my point of view people should just start to use sha256/sha512 signed certificates, no matter if it doesn't work on windows machines ... otherwise they'll never implement these features in their OS. Everybody just simply put some pressure on the guys.
#7 kkBV6 on 2010-02-08 20:17 (Reply)
Hi, no, not a mistake in my web server config, your system doesn't support SNI (several SSL certificates on one IP).
#7.1 Hanno (Homepage) on 2010-02-11 00:02 (Reply)
One more testcase. Works on WinXP+SP2 with IE7, Opera 10 and FF 3.6
#8 Pavel S. (Homepage) on 2010-02-11 00:18 (Reply)
I think the test would be much more convincing if there was a CA, that one could configure to trust, so that we'd be really checking that the path is properly verified. The CAPI used by microsoft can manipulate a cert even when it can't verify it's signature, and that all what is done here as soon as the path isn't verified.

XP/SP3 is the minimum required to use SHA-256 with IE, I believe those who reported succes with SP2 were not actually exerting the use of SHA256 since by clicking trough they were just blindly accepting a cert without any verification.
#9 jmdesp on 2010-03-21 10:55 (Reply)
> I think the test would be much more convincing if there was
> a CA, that one could configure to trust, so that we'd be
> really checking that the path is properly verified.

I have placed the root cert on the page, you can import it:
http://sha2.hboeck.de/sha2.crt
#9.1 Hanno (Homepage) on 2010-03-21 12:11 (Reply)
The https://sha2.hboeck.de/ works fine with me.

But on https://sha512.hboeck.de/ I am getting a certificate issued to *.shokokeks.org using SHA1 (3 hierarchy chain up to a different root).
#10 wqsxgrl on 2010-06-03 10:00 (Reply)
So are there any CAs offering SHA256 signed certificates?

It seems all the CAs I've checked have SHA256 keys in their root stores, but they aren't actually being used yet to sign SSL certs.
#11 nukemjoe on 2010-10-07 01:56 (Reply)
I know this is old but sine I got a hit on SHA256 signature algorithm thought I would add this for others. Some older programs do have issues with this. Currently we have a problem with weblogic 10.3.x (inour case 10.3.6) can't read CA files with SHA256 and has to have JSSE enable to read a server cert (from a outbound request). Just an FYI.
#12 Jack Krouse (Homepage) on 2014-05-07 16:34 (Reply)

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