DKIM check invalid with PHPMailer

Question

I've just install PHPMailer and DKIM and everything seems to be ok. DNS are replicated with DKIM record, RSA key are generated and placed at the right place. But.. result when I send a message is : invalid.

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Message contains this DKIM Signature:
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; l=1713; s=dkim;
    t=1465233482; c=relaxed/simple;
    h=From:To:Date:Subject;
    d=xxxxx.xxx; i=root@localhost;
    z=From:=20=3D?UTF-8?Q?La_Mod=3DC3=3DA9ration_de_CA?=3D=20
    |To:=20cN9Ush6VQgBfiS@dkimvalidator.com
    |Date:=20Mon,=206=20Jun=202016=2019:18:02=20+0200
    |Subject:=20Suppression=20de=20votre=20compte;
    bh=IzoJggwtPQOV/aIyy0WsyBQ2qKwcfHgljU7aOHPA+JI=;
    b=

Signature Information:
v= Version:         1
a= Algorithm:       rsa-sha256
c= Method:          relaxed/simple
d= Domain:          xxxxx.xxx
s= Selector:        dkim
q= Protocol:        dns/txt
bh=                 IzoJggwtPQOV/aIyy0WsyBQ2qKwcfHgljU7aOHPA+JI=
h= Signed Headers:  From:To:Date:Subject
b= Data:            
Public Key DNS Lookup


Building DNS Query for dkim._domainkey.xxxxx.xxx
Retrieved this publickey from DNS: v=DKIM1; k=rsa;p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCh4qoAjuc4qrO01aWQ2wjRnbyuI3wKliRsjbPvGE4neh2ac8WiOyZeuPPoq6LuqNLQbzgkpB49b7Za88D5AOACx7RxY0ahjDF+H76us1BI62yZnAiwhS27aLNlI7DqbbcNURjRNIod/zRs/i1Empgpqf2WFLqneNS/lcADiEA7GQIDAQAB
Validating Signature


result = invalid
Details: bad identity

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Something wrong.. but what ? Is it normal that "b= Data:" is empty ? When I have a look inside de PHPMailer Class, it's pretty normal, code is 'b=;' and nothing else.

Could someone be able to give me more explanations ?

Thanks a lot

FZ

Answer 1

Something is up with your config = the b param should not be empty. If you look at the code you'll see that the base64-encoded signature appended to that string via the response from the DKMIN_sign function, which must mean that something is going wrong inside that function, specifically, the call to openssl_sign must be failing, most likely that it's failing to get your private key.