# Valid S/MIME Header?

**URL:** <https://community.ciphermail.com/t/valid-s-mime-header/370>\
**Category:** Gateway\
**Created:** [July 21, 2014, 4:41pm UTC](https://community.ciphermail.com/t/valid-s-mime-header/370 "2014-07-21T16:41:29Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![lst\_hoe021](https://avatars.discourse-cdn.com/v4/letter/l/58956e/32.png) [@lst\_hoe021](https://community.ciphermail.com/u/lst_hoe021)\
**Post date:** [July 21, 2014, 4:41pm UTC](https://community.ciphermail.com/t/valid-s-mime-header/370/1 "2014-07-21T16:41:29Z")

</div>

Hello,

today we got a mail to a mostly idle domain which has not set "remove  
certificates" so signed e-mail would pass by. The e-mail in question  
was encrypted and was decrypted as it should from my point of view,  
but the messaging system where the mail was finally viewed does only  
display the smime.p7m. The header was  
This is a multipart message in MIME format

--27817437  
Content-Type: application/x-pkcs7-mime; name="=?iso-8859-1?Q?smime.p7m?="  
Content-Transfer-Encoding: Base64  
Content-Disposition: attachment; filename="=?iso-8859-1?Q?smime.p7m?="

which lacks the "smime-type", no? Thunderbird display the mail and  
content fine, but does not show any "Signed" signal for the mail at  
all...

Regards

Andreas

---

<div class="post-metadata">

**Author:** ![martijn](https://dub1.discourse-cdn.com/flex017/user_avatar/community.ciphermail.com/martijn/32/127_2.png) [@martijn](https://community.ciphermail.com/u/martijn)\
**Post date:** [July 21, 2014, 7:19pm UTC](https://community.ciphermail.com/t/valid-s-mime-header/370/2 "2014-07-21T19:19:37Z")

</div>

Since the content type is application/x-pkcs7-mime and name is smime.p7m  
it probably is a S/MIME opaque signed attachment. What is strange is  
that an smime.p7m is normally never used with a multipart message since  
this is not a valid S/MIME message. It looks like the message was opaque  
signed and then the message was changed (disclaimer service?) and then  
encrypted.

Can you send me the message of list so I can investigate the message?

Kind regards,

Martijn Brinkers

> **···**
>
> On 07/21/2014 06:41 PM, lst\_hoe02(a)kwsoft.de wrote:
> 
> > today we got a mail to a mostly idle domain which has not set "remove  
> > certificates" so signed e-mail would pass by. The e-mail in question was  
> > encrypted and was decrypted as it should from my point of view, but the  
> > messaging system where the mail was finally viewed does only display the  
> > smime.p7m. The header was  
> > This is a multipart message in MIME format
> > 
> > --27817437  
> > Content-Type: application/x-pkcs7-mime; name="=?iso-8859-1?Q?smime.p7m?="  
> > Content-Transfer-Encoding: Base64  
> > Content-Disposition: attachment; filename="=?iso-8859-1?Q?smime.p7m?="
> > 
> > which lacks the "smime-type", no? Thunderbird display the mail and  
> > content fine, but does not show any "Signed" signal for the mail at all...
> 
> --  
> CipherMail email encryption
> 
> Open source email encryption gateway with support for S/MIME, OpenPGP  
> and PDF messaging.
> 
> > **[CipherMail email encryption and digital signatures](https://www.ciphermail.com)**
> >
> > Easy to use server-side email encryption for automatic encryption and digital signing of email.
> 
> Twitter: [http://twitter.com/CipherMail](http://twitter.com/CipherMail)