# Header interpretation

**URL:** <https://community.ciphermail.com/t/header-interpretation/170>\
**Category:** Gateway\
**Created:** [February 25, 2011, 8:57am UTC](https://community.ciphermail.com/t/header-interpretation/170 "2011-02-25T08:57:21Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Bernhard\_Heinzle](https://avatars.discourse-cdn.com/v4/letter/b/71e660/32.png) [@Bernhard\_Heinzle](https://community.ciphermail.com/u/Bernhard_Heinzle)\
**Post date:** [February 25, 2011, 8:57am UTC](https://community.ciphermail.com/t/header-interpretation/170/1 "2011-02-25T08:57:21Z")

</div>

Hello,

i'm trying to set up header interpretation rules for MS exchange. But  
i've got the problem that i can define regular expressions for the  
value of the header but not for the name of the header itself.

In my test cases i always had  
X-Djigzo-Info-Signer-Trusted-0-1: True  
or  
X-Djigzo-Info-Signer-Trusted-0-0: True  
(same thing with the "Verified" header).

Are there any other numbering combinations (1-0, 0-2, ...) that can  
occur for the \*-Signer\* header?

Regarding the headers for the encryption:  
Is the existence a header with the name  
X-Djigzo-Info-Encryption-Algorithm-0: and any value sufficient to  
notify the user that the message was encrypted? And is it possible  
that the name of the header contains any other numbers than 0?

Many thanks in advance!

Regards,  
Bernhard

---

<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:** [February 25, 2011, 9:08am UTC](https://community.ciphermail.com/t/header-interpretation/170/2 "2011-02-25T09:08:16Z")

</div>

This is more or less explained in Appendix A of the S/MIME support guide  
but it boils down to this:

An S/MIME message can be encrypted and signed with multiple levels in  
random order. For example a message can be signed, then encrypted and  
then signed again. The numbering scheme shows for which level the  
particular header is. So for example if a message is signed and then  
encrypted (the most standard version) the  
X-Djigzo-Info-Encryption-Algorithm-0 tells you with which encryption  
algorithm the message was encrypted.  
Because the message is 'peeled' from outer layer to inner layer, when a  
message is signed and then encrypted, the outer layer is encrypted,  
hence the -0 level.

To answer your question, if the header  
X-Djigzo-Info-Encryption-Algorithm-0 is present, it means that the outer  
layer was encrypted so that should be sufficient if that's the only  
information you need.

Kind regards,

Martijn

> **···**
>
> On 02/25/2011 09:57 AM, Bernhard Heinzle wrote:
> 
> > Hello,
> > 
> > i'm trying to set up header interpretation rules for MS exchange. But  
> > i've got the problem that i can define regular expressions for the  
> > value of the header but not for the name of the header itself.
> > 
> > In my test cases i always had  
> > X-Djigzo-Info-Signer-Trusted-0-1: True  
> > or  
> > X-Djigzo-Info-Signer-Trusted-0-0: True  
> > (same thing with the "Verified" header).
> > 
> > Are there any other numbering combinations (1-0, 0-2, ...) that can  
> > occur for the \*-Signer\* header?
> > 
> > Regarding the headers for the encryption:  
> > Is the existence a header with the name  
> > X-Djigzo-Info-Encryption-Algorithm-0: and any value sufficient to  
> > notify the user that the message was encrypted? And is it possible  
> > that the name of the header contains any other numbers than 0?
> 
> --  
> Djigzo open source email encryption

---

<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:** [February 25, 2011, 9:38am UTC](https://community.ciphermail.com/t/header-interpretation/170/3 "2011-02-25T09:38:29Z")

</div>

I forgot to answer you question about signing.

Yes other combination are possible but only is special cases. As  
explained in the previous email, there can be multiple levels. In  
addition to that a level can have multiple signers so in theory the  
following \*-Signer\* headers are possible:

\*-Signer\*-N-N where N is a number \>= 0.

In you case however I would only support

\*-Signer\*-0-N

And perhaps even only

\*-Signer\*-0-0 or,  
\*-Signer\*-0-1

All other combinations are possible but almost impossible to explain to  
end-users.

Kind regards,

Martijn

> **···**
>
> On 02/25/2011 09:57 AM, Bernhard Heinzle wrote:
> 
> > i'm trying to set up header interpretation rules for MS exchange. But  
> > i've got the problem that i can define regular expressions for the  
> > value of the header but not for the name of the header itself.
> > 
> > In my test cases i always had  
> > X-Djigzo-Info-Signer-Trusted-0-1: True  
> > or  
> > X-Djigzo-Info-Signer-Trusted-0-0: True  
> > (same thing with the "Verified" header).
> > 
> > Are there any other numbering combinations (1-0, 0-2, ...) that can  
> > occur for the \*-Signer\* header?
> 
> --  
> Djigzo open source email encryption