Ok, there we go: https://github.com/mono/mono/pull/2350 
<https://github.com/mono/mono/pull/2350>

- Alex

> Am 15.12.2015 um 20:37 schrieb Sebastien Pouliot 
> <sebastien.poul...@gmail.com>:
> 
> Hey,
> 
> There should not be any issues changing the default to SHA1, that was an 
> already tested configuration. However a change to SHA256 would require some 
> testing, as some constants might be missing (or did not even exists back in 
> 2003 ;-).
> 
> Sebastien
> 
> On Tue, Dec 15, 2015 at 2:28 PM, Eric Lawrence <bay...@gmail.com 
> <mailto:bay...@gmail.com>> wrote:
> As far as I know, all systems that support MD5 Authenticode signatures also 
> support SHA1 signatures, so breakage from this change seems quite unlikely. 
> 
> (Alas, this is not true of SHA256, which is only supported on modern versions 
> of Windows, and not presently supported by signcode.exe at all).
> 
> On Tue, Dec 15, 2015 at 1:12 PM, Alexander Köplinger 
> <alexander.koeplin...@xamarin.com <mailto:alexander.koeplin...@xamarin.com>> 
> wrote:
> I like it. Does changing the default have any backwards compatibility issues?
> 
> Looks like the default comes from 
> https://github.com/mono/mono/blob/b7a308f660de8174b64697a422abfc7315d07b8c/mcs/class/Mono.Security/Mono.Security.Authenticode/AuthenticodeFormatter.cs#L80
>  
> <https://github.com/mono/mono/blob/b7a308f660de8174b64697a422abfc7315d07b8c/mcs/class/Mono.Security/Mono.Security.Authenticode/AuthenticodeFormatter.cs#L80>
>  so we’d need to decide if we should change it there or make a targeted fix 
> just for signcode.
> 
> - Alex
> 
>> Am 15.12.2015 um 20:00 schrieb Eric Lawrence <bay...@gmail.com 
>> <mailto:bay...@gmail.com>>:
>> 
>> (resend, as Miguel suggested I should join the list)
>> 
>> Today, the signcode application distributed with Mono defaults to using MD5 
>> for Authenticode signing. This has resulted in vulnerable signatures on at 
>> least two broadly distributed projects (CoPilot and WordPress Desktop; see 
>> http://textslashplain.com/2015/12/15/hashes-and-code-signing/ 
>> <http://textslashplain.com/2015/12/15/hashes-and-code-signing/>).
>>  
>> MD5 signatures are dangerous because the collision attacks against MD5 get 
>> better and cheaper with each passing day, and any MD5 signature is 
>> vulnerable to abuse for the lifetime of the signing certificate—the package 
>> WordPress signed last week could be exploited until 11/21/2018 unless 
>> Automattic is willing to revoke their signing certificate before that time 
>> (costly).
>>  
>> SHA1 is considerably stronger than MD5 and signcode already supports it; it 
>> just needs to be made default. The command line argument (-a md5) could be 
>> used for anyone that really needs an MD5 signature for any reason.
>>  
>> Thanks for your consideration!
>>  
>> -Eric Lawrence
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> 
> 
> 
> 
> -- 
> Eric Lawrence
> Bayden Systems
> http://www.bayden.com <http://www.bayden.com/>
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