# Md5 or sha256 hash of the contact's email in custom header

**URL:** https://forum.mautic.org/t/md5-or-sha256-hash-of-the-contacts-email-in-custom-header/19898
**Category:** Product Support
**Created:** [June 17, 2021, 7:03pm UTC](https://forum.mautic.org/t/md5-or-sha256-hash-of-the-contacts-email-in-custom-header/19898 "2021-06-17T19:03:44Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![jf5](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/jf5/32/5339_2.png) [@jf5](https://forum.mautic.org/u/jf5)
#### Post date: [June 17, 2021, 7:03pm UTC](https://forum.mautic.org/t/md5-or-sha256-hash-of-the-contacts-email-in-custom-header/19898/1 "2021-06-17T19:03:44Z")

</div>

**Your software**  
My Mautic version is: 3.3.3  
My PHP version is: 7.3.27  
My Database type and version is: mariadb:10.2

**Your problem**  
My problem is:

Hello,  
I want to get the md5 or sha256 hash of the contact’s email to add it in a custom header.  
`'list-unsubscribe' => '<mailto: brand.{contactfield=emailmd5}@unsub.brand.com?subject=unsubscribe>'`

What do you think is the best way to go?  
Should we create an extra field and pre-generate the md5 hashes (if necessary is it possible to do this without a custom module?)  
Or  
Is there a way to convert the variable {contactfield=email} in hash?

Thank you !