Hello Derek,
Yes it is valid and comes up properly. ; is merely a line break or indicator of end to record value.
For users of cPanel or Plesk:
Take the entire record and add ; in the end. and but them in between double quotes " " if the above doesn't work.
Example:
"p=MIIBIjANBgKbEN+1EeTvppeowIDAQAB;"
Below this is for Derek and Advanced users for information only:
What cPanel or Plesk does after saving with ; at the end is that it adds \ at the end before ; Don't be alarmed these are just indicators of end of record or separators.
p=MIIBIjANBgKbEN+1EeTvppeowIDAQAB\;
But records show up without both when you view the same Public Key on MXtoolbox or DmarcAnalyzer
Though just adding p= is not the right approach. As MXToolbox also complains:
The syntax and semantics of this tag value before being encoded in base64 are defined by the (k) tag.
On dmarcanalyzer.com complains of a missing version:
Unknown DKIM protocol version v=
These are mainly due to unconventional implementations per
RFC 5863 the DKIM RFCs. You can find newer variants here
RFC8463 and
RFC8301
Which are DKIM Version and Signer missing .
v=DKIM1; k=rsa; p=xyz;
This was there before SmarterMail 17 if I remember correctly.
Specifying the version and the signer are two other aspects of it apart from the key to be compliant with the DKIM standards.