Basic example of AMPScript SHA256() function, returning SHA256 hash tag based on the string value

AMPScript Encryption (Simple).html

%%[
SET @CheckForEmail = IsEmailAddress(_SubscriberKey)

IF @CheckForEmail == 'false' THEN
 SET @FinalSubscriberKey = _SubscriberKey
ELSE
 SET @FinalSubscriberKey = SHA256(_SubscriberKey,'UTF-16')
ENDIF

SET @Link = CONCAT('https://[DomainStuffHere]?mcsubkey=', @FinalSubscriberKey)
]%%

<p>
<strong>Staging URL with AMPScript =</strong> <a href="%%=RedirectTo(@Link)=%%">%%=RedirectTo(@Link)=%%</a>
</p>
<p>
  <strong>1. SubscriberKey (original) =</strong> %%_SubscriberKey%%
  <br>
  <strong>2. SubscriberKey (if email true) =</strong> %%=v(@FinalSubscriberKey)=%%
</p>
<hr>
<p>
  Salesforce Documentation: https://developer.salesforce.com/docs/atlas.en-us.noversion.mc-programmatic-content.meta/mc-programmatic-content/SHA256.htm
</p>