View p7m file with openssl
How to view the content of a .p7m file Normally a .p7m file is what in openssl terms is a DER file 1 (note: it work also with cms command). openssl smime -verify -in smime.p7m -inform der -noverify -signer cert.pem -out textdata where: -verify to tell openssl that you will feed a signed mail message on input and outputs the signed data. -noverify do not verify the signers certificate of a signed message.
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