View source for Brand Indicators for Message Identification (BIMI)

[[Category:InboxSys]]
[[Category:Deliverability]]
[[Category:Authentication]]
[[Category:Reputation]]

'''Brand Indicators for Message Identification''', or '''BIMI''', is a specification allowing for the display of brand logos in the inbox. BIMI is currently an RFC [https://datatracker.ietf.org/doc/draft-brand-indicators-for-message-identification/ draft].

=Prerequisites=

BIMI requires a valid and passing [[DMARC]] record, with the policy set to either "reject" or "quarantine". 

=DNS record=

A BIMI DNS record is set on a subdomain named '''default._bimi'''. It contains the following elements:

* A BIMI version (Currently only '''BIMI1''' is available).
* A link to a BIMI '''logo'''.
* Optional: A link to a BIMI certificate ('''VMC''' or '''CMC''').

BIMI DNS records looks like this:

<pre>
$ host -t txt default._bimi.example.com
default._bimi.example.com descriptive text "v=BIMI1; l=https://example.com/logo.svg; a=https://example.com/image/certificate.pem;"
</pre>

==BIMI logo==

The logo that's included in the "v"-switch of the BIMI DNS record should comply to the folowing: 

* It must be in [[wikipedia:SVG_Tiny_P/S|SVG (Tiny P/S)]] format.
* The "version" attribute must be set to "1.2"
* A <title> element must be included that reflects the company name.
* A <desc> (i.e. the "description") element is not required, but this should be included to support accessibility.
* The image must be sqare. Length and width should have the same value.
* The image size shouldn't exceed 32 Kb.
* No external links or references (other than to the specified XML namespaces) should be included.
* No scripts, animation, or other interactive elements should be included.
* No "x=" or "y=" attributes should be included within the <svg> root element.
* The image should not have a transparent background.

==BIMI certificate==

The optional BIMI certificate is used to digitally sign the logo and the [[RFC5322.From|senderdomain]]. It contains other elements, such as an organisation name, a list of domains signed by this certificate and an expiration date. There are 2 types of certificate: '''VMC''' and '''CMC'''. CMC certificates are slightly less expensive than VMC certificates. They are issued by certification authorities (Entrust or DigiCert) recognized by the [https://bimigroup.org/ BIMI Working Group]. 

It is [https://community.letsencrypt.org/t/verified-mark-certificates/176835 not possible to create valid VMC or CMC certificates] with a free service such as [https://letsencrypt.org Letsencrypt].

===Difference between VMC and CMC certificates===

{| class="wikitable"
|+ VMC vs. CMC
! Requirement !! VMC !! CMC
|-
! scope="row"| Trademark Registration
| Yes
| No 
|-
! scope="row"| Logo in use
| Can be used immediately
| Must have been in use since 1 year
|}

=BIMI adoption by ISPs=

{| class="wikitable"
|+ Email clients supporting BIMI
! Client !! VMC !! CMC !! Self-Asserted !! Comment
|-
! scope="row"| AOL / Yahoo!
| No
| No
| Yes
| Only for bulk messages from high-reputation domains
|-
! scope="row"| Apple Mail
| Yes
| No
| No
|-
! scope="row"| Fastmail
| No
| No
| Yes
|-
! scope="row"| Gmail
| Yes
| Yes
| No
| Only VMC certificates get a blue checkmark.
|-
! scope="row"| La Poste
| Yes
| No
| Yes
| Domains without VMCs must be submitted and manually verified by La Poste.
|}

=Useful links=

* [https://datatracker.ietf.org/doc/draft-brand-indicators-for-message-identification/ BIMI draft]
* [[wikipedia:Brand_Indicators_for_Message_Identification]]
* [https://bimigroup.org/creating-bimi-svg-logo-files/ Creating BIMI svg logo files]