DKIM-Signature header Email Security.Cloud

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• Email Security.cloud

Issue/Introduction

 

Resolution

Here is a breakdown of the contents in a DKIM-Signature header.

DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=sample.info; s=s20171208; t=1515030923; [email protected];     
bh=kdobFob7juw8qlrpRkjQtVHfb2UCqhKVM5nC/ztx178=;
h=From:Content-Type:Content-Transfer-Encoding:Mime-Version:Date:Subject:Message-Id:To;
b=HMEQb11VS842Y5xrZgAnvv59eBvBkfxZ7R4Ql0TI/Zuhy/nKax1khUhw4wuMtB47Oi
qNFpzp6ueNxBc1i07+81BzitnA+1saXuUnFKxo2yRqNhlOeU/8de6A99IPULnWodv+5H
dMoLjTOjhJ7oGeqPj/+1KfiNVnV3whgjUhY4E=

"v" is the version number

"a" is the hash algorithm used

"c" is the canonization

"d" is the signing domain

"s" is the selector

"t" is the epoch timestamp marking when the message was signed

"i" is the identity of the user or program for which the message has been signed. This can be omitted but if present the domain must match `d` although the username before the `@` may be dropped

"bh" is the hash for the body

"h" is the header fields signed

"b" is the signature key for the body and header hash