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SMIME(1)                                           OpenSSL                                          SMIME(1)



NAME
       smime - S/MIME utility

SYNOPSIS
       openssl smime [-encrypt] [-decrypt] [-sign] [-verify] [-pk7out] [-des] [-des3] [-rc2-40] [-rc2-64]
       [-rc2-128] [-aes128] [-aes192] [-aes256] [-camellia128] [-camellia192] [-camellia256] [-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]...

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

COMMAND OPTIONS
       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
           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
           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
           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
           verify signed mail. Expects a signed mail message on input and outputs the signed data. Both
           clear text and opaque signing is supported.

       -pk7out
           takes an input message and writes out a PEM encoded PKCS#7 structure.

       -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 example 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 type.

       -text
           this option adds plain text (text/plain) MIME headers to the supplied 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 -aes128 -aes192 -aes256 -camellia128 -camellia192 -camellia256
           the encryption algorithm to use. DES (56 bits), triple DES (168 bits), 40, 64 or 128 bit RC2,
           128, 192 or 256 bit AES, or 128, 192 or 256 bit Camellia respectively.  If not specified 40 bit
           RC2 is used. Only used with -encrypt.

       -nointern
           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 however.

       -noverify
           do not verify the signers certificate of a signed message.

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

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

       -nocerts
           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).

       -noattr
           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.

       -binary
           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.

       -nodetach
           when signing a message use opaque signing: this form is more resistant 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 certificate must match one of the
           recipients of the message or an error occurs.

       -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 number generator, or an EGD socket
           (see RAND_egd(3)).  Multiple files can be specified separated by a OS-dependent character.  The
           separator is ; for MS-Windows, , for OpenVMS, and : for all others.

       cert.pem...
           one or more certificates of message recipients: used when encrypting 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.

NOTES
       The MIME message must be sent without any blank lines between the headers 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 necessary 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 headers.

       A "signed and encrypted" message is one where a signed message is then encrypted. This can be
       produced by encrypting an already signed message: 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.

EXIT CODES
       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 message.

       4   an error occurred decrypting or verifying the message.

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

EXAMPLES
       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 headers:

        openssl smime -sign -in in.txt -text -signer mycert.pem \
               -from steve@openssl.org -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 steve@openssl.org \
               -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 steve@openssl.org -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 signature by line wrapping the base64 encoded structure and
       surrounding it with:

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

       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

       Create an encrypted message using 128 bit Camellia:

        openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem

BUGS
       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 encryption 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.



50                                               2013-03-05                                         SMIME(1)

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