Tried so far OpenSSL smime -decrypt -in 'Secret.p7m' -inkey 'Key.pem' > Result.txtħ548:error:0906D06C:PEM routines:PEM_read_bio:no start line.\crypto\pem\pem_libĬontent-Type: application/pkcs7-mime name='smime.p7m' Ĭontent-Disposition: attachment filename='smime. CipherMail for Android is an Android application which can be used with your existing Android mail application to send and receive S/MIME digitally signed. Security tools downloads - P7S Viewer by Secure Soft and many more programs are available for instant and free download. Both desktop and mobile devices enable you to view and (sometimes) edit these files, depending on the software used. Windows, Mac, and Linux operating systems can be used to view P7M files. My knownledge about security is limited so I need some help here. The P7M File Extension are listed predominantly as Encrypted Files.