SMIME(1)                            OpenSSL                           SMIME(1)

       smime - S/MIME utility

       openssl smime [-encrypt] [-decrypt] [-sign] [-verify] [-pk7out] [-des]
       [-des3] [-rc2-40] [-rc2-64] [-rc2-128] [-in file] [-certfile file]
       [-signer file] [-recip  file] [-inform SMIME|PEM|DER] [-passin arg]
       [-inkey file] [-out file] [-outform SMIME|PEM|DER] [-content file] [-to
       addr] [-from ad] [-subject s] [-text] [-rand file(s)] [cert.pem]...

       The smime command handles S/MIME mail. It can encrypt, decrypt, sign
       and verify S/MIME messages.

       There are five operation options that set the type of operation to be
       performed.  The meaning of the other options varies according to the
       operation type.

           encrypt mail for the given recipient certificates. Input file is
           the message to be encrypted. The output file is the encrypted mail
           in MIME format.

           decrypt mail using the supplied certificate and private key.
           Expects an encrypted mail message in MIME format for the input
           file. The decrypted mail is written to the output file.

           sign mail using the supplied certificate and private key. Input
           file is the message to be signed. The signed message in MIME format
           is written to the output file.

           verify signed mail. Expects a signed mail message on input and out-
           puts the signed data. Both clear text and opaque signing is sup-

           takes an input message and writes out a PEM encoded PKCS#7 struc-

       -in filename
           the input message to be encrypted or signed or the MIME message to
           be decrypted or verified.

       -inform SMIME|PEM|DER
           this specifies the input format for the PKCS#7 structure. The
           default is SMIME which reads an S/MIME format message. PEM and DER
           format change this to expect PEM and DER format PKCS#7 structures
           instead. This currently only affects the input format of the PKCS#7
           structure, if no PKCS#7 structure is being input (for example with
           -encrypt or -sign) this option has no effect.

       -out filename
           the message text that has been decrypted or verified or the output
           MIME format message that has been signed or verified.

       -outform SMIME|PEM|DER
           this specifies the output format for the PKCS#7 structure. The
           default is SMIME which write an S/MIME format message. PEM and DER
           format change this to write PEM and DER format PKCS#7 structures
           instead. This currently only affects the output format of the
           PKCS#7 structure, if no PKCS#7 structure is being output (for exam-
           ple with -verify or -decrypt) this option has no effect.

       -content filename
           This specifies a file containing the detached content, this is only
           useful with the -verify command. This is only usable if the PKCS#7
           structure is using the detached signature form where the content is
           not included. This option will override any content if the input
           format is S/MIME and it uses the multipart/signed MIME content

           this option adds plain text (text/plain) MIME headers to the sup-
           plied message if encrypting or signing. If decrypting or verifying
           it strips off text headers: if the decrypted or verified message is
           not of MIME type text/plain then an error occurs.

       -CAfile file
           a file containing trusted CA certificates, only used with -verify.

       -CApath dir
           a directory containing trusted CA certificates, only used with
           -verify. This directory must be a standard certificate directory:
           that is a hash of each subject name (using x509 -hash) should be
           linked to each certificate.

       -des -des3 -rc2-40 -rc2-64 -rc2-128
           the encryption algorithm to use. DES (56 bits), triple DES (168
           bits) or 40, 64 or 128 bit RC2 respectively if not specified 40 bit
           RC2 is used. Only used with -encrypt.

           when verifying a message normally certificates (if any) included in
           the message are searched for the signing certificate. With this
           option only the certificates specified in the -certfile option are
           used.  The supplied certificates can still be used as untrusted CAs

           do not verify the signers certificate of a signed message.

           do not do chain verification of signers certificates: that is don't
           use the certificates in the signed message as untrusted CAs.

           don't try to verify the signatures on the message.

           when signing a message the signer's certificate is normally
           included with this option it is excluded. This will reduce the size
           of the signed message but the verifier must have a copy of the
           signers certificate available locally (passed using the -certfile
           option for example).

           normally when a message is signed a set of attributes are included
           which include the signing time and supported symmetric algorithms.
           With this option they are not included.

           normally the input message is converted to "canonical" format which
           is effectively using CR and LF as end of line: as required by the
           S/MIME specification. When this option is present no translation
           occurs. This is useful when handling binary data which may not be
           in MIME format.

           when signing a message use opaque signing: this form is more resis-
           tant to translation by mail relays but it cannot be read by mail
           agents that do not support S/MIME.  Without this option cleartext
           signing with the MIME type multipart/signed is used.

       -certfile file
           allows additional certificates to be specified. When signing these
           will be included with the message. When verifying these will be
           searched for the signers certificates. The certificates should be
           in PEM format.

       -signer file
           the signers certificate when signing a message. If a message is
           being verified then the signers certificates will be written to
           this file if the verification was successful.

       -recip file
           the recipients certificate when decrypting a message. This certifi-
           cate must match one of the recipients of the message or an error

       -inkey file
           the private key to use when signing or decrypting. This must match
           the corresponding certificate. If this option is not specified then
           the private key must be included in the certificate file specified
           with the -recip or -signer file.

       -passin arg
           the private key password source. For more information about the
           format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).

       -rand file(s)
           a file or files containing random data used to seed the random num-
           ber generator, or an EGD socket (see RAND_egd(3)).  Multiple files
           can be specified separated by a OS-dependent character.  The sepa-
           rator is ; for MS-Windows, , for OpenVMS, and : for all others.

           one or more certificates of message recipients: used when encrypt-
           ing a message.

       -to, -from, -subject
           the relevant mail headers. These are included outside the signed
           portion of a message so they may be included manually. If signing
           then many S/MIME mail clients check the signers certificate's email
           address matches that specified in the From: address.

       The MIME message must be sent without any blank lines between the head-
       ers and the output. Some mail programs will automatically add a blank
       line. Piping the mail directly to sendmail is one way to achieve the
       correct format.

       The supplied message to be signed or encrypted must include the neces-
       sary MIME headers or many S/MIME clients wont display it properly (if
       at all). You can use the -text option to automatically add plain text

       A "signed and encrypted" message is one where a signed message is then
       encrypted. This can be produced by encrypting an already signed mes-
       sage: see the examples section.

       This version of the program only allows one signer per message but it
       will verify multiple signers on received messages. Some S/MIME clients
       choke if a message contains multiple signers. It is possible to sign
       messages "in parallel" by signing an already signed message.

       The options -encrypt and -decrypt reflect common usage in S/MIME
       clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
       encrypted data is used for other purposes.

       0   the operation was completely successfully.

       1   an error occurred parsing the command options.

       2   one of the input files could not be read.

       3   an error occurred creating the PKCS#7 file or when reading the MIME

       4   an error occurred decrypting or verifying the message.

       5   the message was verified correctly but an error occurred writing
           out the signers certificates.

       Create a cleartext signed message:

        openssl smime -sign -in message.txt -text -out mail.msg \
               -signer mycert.pem

       Create and opaque signed message

        openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
               -signer mycert.pem

       Create a signed message, include some additional certificates and read
       the private key from another file:

        openssl smime -sign -in in.txt -text -out mail.msg \
               -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem

       Send a signed message under Unix directly to sendmail, including head-

        openssl smime -sign -in in.txt -text -signer mycert.pem \
               -from -to someone@somewhere \
               -subject "Signed message" | sendmail someone@somewhere

       Verify a message and extract the signer's certificate if successful:

        openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt

       Send encrypted mail using triple DES:

        openssl smime -encrypt -in in.txt -from \
               -to someone@somewhere -subject "Encrypted message" \
               -des3 user.pem -out mail.msg

       Sign and encrypt mail:

        openssl smime -sign -in ml.txt -signer my.pem -text \
               | openssl smime -encrypt -out mail.msg \
               -from -to someone@somewhere \
               -subject "Signed and Encrypted message" -des3 user.pem

       Note: the encryption command does not include the -text option because
       the message being encrypted already has MIME headers.

       Decrypt mail:

        openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem

       The output from Netscape form signing is a PKCS#7 structure with the
       detached signature format. You can use this program to verify the sig-
       nature by line wrapping the base64 encoded structure and surrounding it

        -----BEGIN PKCS7-----
        -----END PKCS7-----

       and using the command,

        openssl smime -verify -inform PEM -in signature.pem -content content.txt

       alternatively you can base64 decode the signature and use

        openssl smime -verify -inform DER -in signature.der -content content.txt

       The MIME parser isn't very clever: it seems to handle most messages
       that I've thrown at it but it may choke on others.

       The code currently will only write out the signer's certificate to a
       file: if the signer has a separate encryption certificate this must be
       manually extracted. There should be some heuristic that determines the
       correct encryption certificate.

       Ideally a database should be maintained of a certificates for each
       email address.

       The code doesn't currently take note of the permitted symmetric encryp-
       tion algorithms as supplied in the SMIMECapabilities signed attribute.
       this means the user has to manually include the correct encryption
       algorithm. It should store the list of permitted ciphers in a database
       and only use those.

       No revocation checking is done on the signer's certificate.

       The current code can only handle S/MIME v2 messages, the more complex
       S/MIME v3 structures may cause parsing errors.

0.9.7a                            2002-11-09                          SMIME(1)