I want to sign this canonical HEADER+DKIM-SIGNATURE with RSA1 and private key for DKIM verification :
subject:ddddd
from:btt@domain.com
to:email@gmail.com
dkim-signature:v=1; a=rsa-sha1; c=relaxed/relaxed; s=selector1; d=domain.com; h=Subject:From:To; i=btt@domain.com; bh=rcr9nmkeqsjAGn29CUiUNJFRSmc=; b=

But i get a different signature when i compare the generated one with the signature i get from email header using PowerMta.

Can you notice any issue on the format of my content?