the main question of this message is how to get the true ciphertext from S/MIME file?
I created RSA keys and encrypted a message with S/MIME as follow :
1) generate private key : openssl genrsa -out maCle.pem 1024
2) create certificate(public key) : openssl req -new -x509 -key privkey.pem -out certif.pem -days 1095
3) encrypt using smime : openssl smime -encrypt -in plaintext -text -out mail.msg certif.pem
mail.msg looks like:
MIME-Version: 1.0
Content-Disposition: attachment; filename="smime.p7m"
Content-Type: application/x-pkcs7-mime; smime-type=enveloped-data; name="smime.p7m"
Content-Transfer-Encoding: base64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when I decode the base64 from mail.msg I can see informations that are in my certificate (certif.pem). So it seems mail.msg contains a certificate which is NOT encrypted (is that right?) So how can I extract this certificate and how can I extract the true ciphertext that matches with my plaintext?
I thought the certificate in mail.msg was the same in certif.pem but the beginning doesn't match except the first three characters :
certif.pem : MIIC3DCCAkWgAwI...
mail.msg : MIIBnQYJKoZIhvc...
so what is this certificate?