# Issue with S/MIME decryption most likley caused by Exchange attaching corporate signatures

**URL:** <https://community.ciphermail.com/t/issue-with-s-mime-decryption-most-likley-caused-by-exchange-attaching-corporate-signatures/614>\
**Category:** Gateway\
**Created:** [April 23, 2018, 10:31am UTC](https://community.ciphermail.com/t/issue-with-s-mime-decryption-most-likley-caused-by-exchange-attaching-corporate-signatures/614 "2018-04-23T10:31:55Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Olaf\_Schwarz1](https://avatars.discourse-cdn.com/v4/letter/o/3da27b/32.png) [@Olaf\_Schwarz1](https://community.ciphermail.com/u/Olaf_Schwarz1)\
**Post date:** [April 23, 2018, 10:31am UTC](https://community.ciphermail.com/t/issue-with-s-mime-decryption-most-likley-caused-by-exchange-attaching-corporate-signatures/614/1 "2018-04-23T10:31:55Z")

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Looked good in first tests.  
Thanks for helping out.

Best regards  
Olaf

> **···**
>
> On 04/20/2018 06:08 PM, Martijn Brinkers wrote:
> 
> > Opaque signed are signed message but in encoded form and require a mail  
> > client that supports S/MIME. Clear text signed messages can be read with  
> > a non S/MIME aware mail client. Outlook opaquely signs a message before  
> > encrypting it.
> > 
> > Can you check with a mail client that supports S/MIME (Thunderbird,  
> > Outlook etc.) whether you can read the message?
> > 
> > If the message is opaquely signed, the "solution" is to have ciphermail  
> > remove the signature. The result in then a normal message.