666 lines
21 KiB
Plaintext
666 lines
21 KiB
Plaintext
=pod
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=head1 NAME
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openssl-cms,
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cms - CMS utility
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=head1 SYNOPSIS
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B<openssl> B<cms>
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[B<-encrypt>]
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[B<-decrypt>]
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[B<-sign>]
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[B<-verify>]
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[B<-cmsout>]
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[B<-resign>]
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[B<-data_create>]
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[B<-data_out>]
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[B<-digest_create>]
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[B<-digest_verify>]
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[B<-compress>]
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[B<-uncompress>]
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[B<-EncryptedData_encrypt>]
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[B<-sign_receipt>]
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[B<-verify_receipt receipt>]
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[B<-in filename>]
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[B<-inform SMIME|PEM|DER>]
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[B<-rctform SMIME|PEM|DER>]
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[B<-out filename>]
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[B<-outform SMIME|PEM|DER>]
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[B<-stream -indef -noindef>]
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[B<-noindef>]
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[B<-content filename>]
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[B<-text>]
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[B<-noout>]
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[B<-print>]
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[B<-CAfile file>]
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[B<-CApath dir>]
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[B<-no_alt_chains>]
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[B<-md digest>]
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[B<-[cipher]>]
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[B<-nointern>]
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[B<-no_signer_cert_verify>]
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[B<-nocerts>]
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[B<-noattr>]
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[B<-nosmimecap>]
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[B<-binary>]
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[B<-nodetach>]
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[B<-certfile file>]
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[B<-certsout file>]
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[B<-signer file>]
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[B<-recip file>]
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[B<-keyid>]
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[B<-receipt_request_all -receipt_request_first>]
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[B<-receipt_request_from emailaddress>]
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[B<-receipt_request_to emailaddress>]
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[B<-receipt_request_print>]
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[B<-secretkey key>]
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[B<-secretkeyid id>]
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[B<-econtent_type type>]
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[B<-inkey file>]
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[B<-keyopt name:parameter>]
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[B<-passin arg>]
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[B<-rand file(s)>]
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[B<cert.pem...>]
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[B<-to addr>]
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[B<-from addr>]
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[B<-subject subj>]
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[cert.pem]...
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=head1 DESCRIPTION
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The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
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verify, compress and uncompress S/MIME messages.
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=head1 COMMAND OPTIONS
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There are fourteen operation options that set the type of operation to be
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performed. The meaning of the other options varies according to the operation
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type.
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=over 4
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=item B<-encrypt>
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encrypt mail for the given recipient certificates. Input file is the message
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to be encrypted. The output file is the encrypted mail in MIME format. The
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actual CMS type is <B>EnvelopedData<B>.
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Note that no revocation check is done for the recipient cert, so if that
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key has been compromised, others may be able to decrypt the text.
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=item B<-decrypt>
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decrypt mail using the supplied certificate and private key. Expects an
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encrypted mail message in MIME format for the input file. The decrypted mail
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is written to the output file.
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=item B<-debug_decrypt>
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this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
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with caution: see the notes section below.
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=item B<-sign>
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sign mail using the supplied certificate and private key. Input file is
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the message to be signed. The signed message in MIME format is written
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to the output file.
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=item B<-verify>
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verify signed mail. Expects a signed mail message on input and outputs
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the signed data. Both clear text and opaque signing is supported.
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=item B<-cmsout>
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takes an input message and writes out a PEM encoded CMS structure.
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=item B<-resign>
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resign a message: take an existing message and one or more new signers.
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=item B<-data_create>
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Create a CMS B<Data> type.
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=item B<-data_out>
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B<Data> type and output the content.
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=item B<-digest_create>
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Create a CMS B<DigestedData> type.
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=item B<-digest_verify>
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Verify a CMS B<DigestedData> type and output the content.
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=item B<-compress>
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Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
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support for this option to work, otherwise it will output an error.
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=item B<-uncompress>
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Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
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compiled with B<zlib> support for this option to work, otherwise it will
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output an error.
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=item B<-EncryptedData_encrypt>
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Encrypt content using supplied symmetric key and algorithm using a CMS
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B<EncrytedData> type and output the content.
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=item B<-sign_receipt>
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Generate and output a signed receipt for the supplied message. The input
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message B<must> contain a signed receipt request. Functionality is otherwise
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similar to the B<-sign> operation.
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=item B<-verify_receipt receipt>
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Verify a signed receipt in filename B<receipt>. The input message B<must>
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contain the original receipt request. Functionality is otherwise similar
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to the B<-verify> operation.
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=item B<-in filename>
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the input message to be encrypted or signed or the message to be decrypted
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or verified.
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=item B<-inform SMIME|PEM|DER>
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this specifies the input format for the CMS structure. The default
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is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
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format change this to expect PEM and DER format CMS structures
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instead. This currently only affects the input format of the CMS
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structure, if no CMS structure is being input (for example with
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B<-encrypt> or B<-sign>) this option has no effect.
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=item B<-rctform SMIME|PEM|DER>
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specify the format for a signed receipt for use with the B<-receipt_verify>
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operation.
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=item B<-out filename>
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the message text that has been decrypted or verified or the output MIME
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format message that has been signed or verified.
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=item B<-outform SMIME|PEM|DER>
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this specifies the output format for the CMS structure. The default
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is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
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format change this to write PEM and DER format CMS structures
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instead. This currently only affects the output format of the CMS
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structure, if no CMS structure is being output (for example with
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B<-verify> or B<-decrypt>) this option has no effect.
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=item B<-stream -indef -noindef>
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the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
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for encoding operations. This permits single pass processing of data without
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the need to hold the entire contents in memory, potentially supporting very
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large files. Streaming is automatically set for S/MIME signing with detached
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data if the output format is B<SMIME> it is currently off by default for all
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other operations.
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=item B<-noindef>
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disable streaming I/O where it would produce and indefinite length constructed
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encoding. This option currently has no effect. In future streaming will be
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enabled by default on all relevant operations and this option will disable it.
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=item B<-content filename>
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This specifies a file containing the detached content, this is only
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useful with the B<-verify> command. This is only usable if the CMS
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structure is using the detached signature form where the content is
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not included. This option will override any content if the input format
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is S/MIME and it uses the multipart/signed MIME content type.
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=item B<-text>
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this option adds plain text (text/plain) MIME headers to the supplied
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message if encrypting or signing. If decrypting or verifying it strips
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off text headers: if the decrypted or verified message is not of MIME
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type text/plain then an error occurs.
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=item B<-noout>
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for the B<-cmsout> operation do not output the parsed CMS structure. This
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is useful when combined with the B<-print> option or if the syntax of the CMS
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structure is being checked.
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=item B<-print>
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for the B<-cmsout> operation print out all fields of the CMS structure. This
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is mainly useful for testing purposes.
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=item B<-CAfile file>
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a file containing trusted CA certificates, only used with B<-verify>.
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=item B<-CApath dir>
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a directory containing trusted CA certificates, only used with
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B<-verify>. This directory must be a standard certificate directory: that
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is a hash of each subject name (using B<x509 -hash>) should be linked
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to each certificate.
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=item B<-md digest>
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digest algorithm to use when signing or resigning. If not present then the
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default digest algorithm for the signing key will be used (usually SHA1).
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=item B<-[cipher]>
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the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
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or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
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EVP_get_cipherbyname() function) can also be used preceded by a dash, for
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example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
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supported by your version of OpenSSL.
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If not specified triple DES is used. Only used with B<-encrypt> and
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B<-EncryptedData_create> commands.
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=item B<-nointern>
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when verifying a message normally certificates (if any) included in
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the message are searched for the signing certificate. With this option
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only the certificates specified in the B<-certfile> option are used.
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The supplied certificates can still be used as untrusted CAs however.
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=item B<-no_signer_cert_verify>
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do not verify the signers certificate of a signed message.
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=item B<-nocerts>
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when signing a message the signer's certificate is normally included
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with this option it is excluded. This will reduce the size of the
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signed message but the verifier must have a copy of the signers certificate
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available locally (passed using the B<-certfile> option for example).
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=item B<-noattr>
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normally when a message is signed a set of attributes are included which
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include the signing time and supported symmetric algorithms. With this
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option they are not included.
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=item B<-nosmimecap>
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exclude the list of supported algorithms from signed attributes, other options
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such as signing time and content type are still included.
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=item B<-binary>
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normally the input message is converted to "canonical" format which is
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effectively using CR and LF as end of line: as required by the S/MIME
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specification. When this option is present no translation occurs. This
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is useful when handling binary data which may not be in MIME format.
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=item B<-nodetach>
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when signing a message use opaque signing: this form is more resistant
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to translation by mail relays but it cannot be read by mail agents that
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do not support S/MIME. Without this option cleartext signing with
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the MIME type multipart/signed is used.
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=item B<-certfile file>
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allows additional certificates to be specified. When signing these will
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be included with the message. When verifying these will be searched for
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the signers certificates. The certificates should be in PEM format.
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=item B<-certsout file>
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any certificates contained in the message are written to B<file>.
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=item B<-signer file>
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a signing certificate when signing or resigning a message, this option can be
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used multiple times if more than one signer is required. If a message is being
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verified then the signers certificates will be written to this file if the
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verification was successful.
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=item B<-recip file>
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when decrypting a message this specifies the recipients certificate. The
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certificate must match one of the recipients of the message or an error
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occurs.
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When encrypting a message this option may be used multiple times to specify
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each recipient. This form B<must> be used if customised parameters are
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required (for example to specify RSA-OAEP).
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Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
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option.
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=item B<-keyid>
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use subject key identifier to identify certificates instead of issuer name and
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serial number. The supplied certificate B<must> include a subject key
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identifier extension. Supported by B<-sign> and B<-encrypt> options.
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=item B<-receipt_request_all -receipt_request_first>
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for B<-sign> option include a signed receipt request. Indicate requests should
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be provided by all receipient or first tier recipients (those mailed directly
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and not from a mailing list). Ignored it B<-receipt_request_from> is included.
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=item B<-receipt_request_from emailaddress>
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for B<-sign> option include a signed receipt request. Add an explicit email
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address where receipts should be supplied.
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=item B<-receipt_request_to emailaddress>
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Add an explicit email address where signed receipts should be sent to. This
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option B<must> but supplied if a signed receipt it requested.
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=item B<-receipt_request_print>
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For the B<-verify> operation print out the contents of any signed receipt
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requests.
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=item B<-secretkey key>
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specify symmetric key to use. The key must be supplied in hex format and be
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consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
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B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
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with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
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content encryption key using an AES key in the B<KEKRecipientInfo> type.
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=item B<-secretkeyid id>
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the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
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This option B<must> be present if the B<-secretkey> option is used with
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B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
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relevant key if it is not supplied then an attempt is used to decrypt any
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B<KEKRecipientInfo> structures.
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=item B<-econtent_type type>
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set the encapsulated content type to B<type> if not supplied the B<Data> type
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is used. The B<type> argument can be any valid OID name in either text or
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numerical format.
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=item B<-inkey file>
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the private key to use when signing or decrypting. This must match the
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corresponding certificate. If this option is not specified then the
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private key must be included in the certificate file specified with
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the B<-recip> or B<-signer> file. When signing this option can be used
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multiple times to specify successive keys.
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=item B<-keyopt name:opt>
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for signing and encryption this option can be used multiple times to
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set customised parameters for the preceding key or certificate. It can
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currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
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or to modify default parameters for ECDH.
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=item B<-passin arg>
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the private key password source. For more information about the format of B<arg>
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see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
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=item B<-rand file(s)>
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a file or files containing random data used to seed the random number
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generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
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Multiple files can be specified separated by a OS-dependent character.
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The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
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all others.
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=item B<cert.pem...>
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one or more certificates of message recipients: used when encrypting
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a message.
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=item B<-to, -from, -subject>
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the relevant mail headers. These are included outside the signed
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portion of a message so they may be included manually. If signing
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then many S/MIME mail clients check the signers certificate's email
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address matches that specified in the From: address.
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=item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig -no_alt_chains>
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Set various certificate chain valiadition option. See the
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L<B<verify>|verify(1)> manual page for details.
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=back
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=head1 NOTES
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The MIME message must be sent without any blank lines between the
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headers and the output. Some mail programs will automatically add
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a blank line. Piping the mail directly to sendmail is one way to
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achieve the correct format.
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The supplied message to be signed or encrypted must include the
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necessary MIME headers or many S/MIME clients wont display it
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properly (if at all). You can use the B<-text> option to automatically
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add plain text headers.
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A "signed and encrypted" message is one where a signed message is
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then encrypted. This can be produced by encrypting an already signed
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message: see the examples section.
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This version of the program only allows one signer per message but it
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will verify multiple signers on received messages. Some S/MIME clients
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choke if a message contains multiple signers. It is possible to sign
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messages "in parallel" by signing an already signed message.
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The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
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clients. Strictly speaking these process CMS enveloped data: CMS
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encrypted data is used for other purposes.
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The B<-resign> option uses an existing message digest when adding a new
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signer. This means that attributes must be present in at least one existing
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signer using the same message digest or this operation will fail.
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The B<-stream> and B<-indef> options enable experimental streaming I/O support.
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As a result the encoding is BER using indefinite length constructed encoding
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and no longer DER. Streaming is supported for the B<-encrypt> operation and the
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B<-sign> operation if the content is not detached.
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Streaming is always used for the B<-sign> operation with detached data but
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since the content is no longer part of the CMS structure the encoding
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remains DER.
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If the B<-decrypt> option is used without a recipient certificate then an
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attempt is made to locate the recipient by trying each potential recipient
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in turn using the supplied private key. To thwart the MMA attack
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(Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
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tried whether they succeed or not and if no recipients match the message
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is "decrypted" using a random key which will typically output garbage.
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The B<-debug_decrypt> option can be used to disable the MMA attack protection
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and return an error if no recipient can be found: this option should be used
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with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
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=head1 EXIT CODES
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=over 4
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=item Z<>0
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the operation was completely successfully.
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=item Z<>1
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an error occurred parsing the command options.
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=item Z<>2
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one of the input files could not be read.
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=item Z<>3
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an error occurred creating the CMS file or when reading the MIME
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message.
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=item Z<>4
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an error occurred decrypting or verifying the message.
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=item Z<>5
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the message was verified correctly but an error occurred writing out
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the signers certificates.
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=back
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=head1 COMPATIBILITY WITH PKCS#7 format.
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The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
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utility supports Cryptographic Message Syntax format. Use of some features
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will result in messages which cannot be processed by applications which only
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support the older format. These are detailed below.
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The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
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The B<-outform PEM> option uses different headers.
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The B<-compress> option.
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The B<-secretkey> option when used with B<-encrypt>.
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The use of PSS with B<-sign>.
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The use of OAEP or non-RSA keys with B<-encrypt>.
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Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
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be processed by the older B<smime> command.
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=head1 EXAMPLES
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Create a cleartext signed message:
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|
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openssl cms -sign -in message.txt -text -out mail.msg \
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-signer mycert.pem
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|
|
Create an opaque signed message
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|
|
openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
|
|
-signer mycert.pem
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|
|
|
Create a signed message, include some additional certificates and
|
|
read the private key from another file:
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|
|
|
openssl cms -sign -in in.txt -text -out mail.msg \
|
|
-signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
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|
|
|
Create a signed message with two signers, use key identifier:
|
|
|
|
openssl cms -sign -in message.txt -text -out mail.msg \
|
|
-signer mycert.pem -signer othercert.pem -keyid
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|
|
|
Send a signed message under Unix directly to sendmail, including headers:
|
|
|
|
openssl cms -sign -in in.txt -text -signer mycert.pem \
|
|
-from steve@openssl.org -to someone@somewhere \
|
|
-subject "Signed message" | sendmail someone@somewhere
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|
|
|
Verify a message and extract the signer's certificate if successful:
|
|
|
|
openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
|
|
|
|
Send encrypted mail using triple DES:
|
|
|
|
openssl cms -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 cms -sign -in ml.txt -signer my.pem -text \
|
|
| openssl cms -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 B<-text> option because the
|
|
message being encrypted already has MIME headers.
|
|
|
|
Decrypt mail:
|
|
|
|
openssl cms -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-----
|
|
|
|
and using the command,
|
|
|
|
openssl cms -verify -inform PEM -in signature.pem -content content.txt
|
|
|
|
alternatively you can base64 decode the signature and use
|
|
|
|
openssl cms -verify -inform DER -in signature.der -content content.txt
|
|
|
|
Create an encrypted message using 128 bit Camellia:
|
|
|
|
openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
|
|
|
|
Add a signer to an existing message:
|
|
|
|
openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
|
|
|
|
Sign mail using RSA-PSS:
|
|
|
|
openssl cms -sign -in message.txt -text -out mail.msg \
|
|
-signer mycert.pem -keyopt rsa_padding_mode:pss
|
|
|
|
Create encrypted mail using RSA-OAEP:
|
|
|
|
openssl cms -encrypt -in plain.txt -out mail.msg \
|
|
-recip cert.pem -keyopt rsa_padding_mode:oaep
|
|
|
|
Use SHA256 KDF with an ECDH certificate:
|
|
|
|
openssl cms -encrypt -in plain.txt -out mail.msg \
|
|
-recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
|
|
|
|
=head1 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.
|
|
|
|
=head1 HISTORY
|
|
|
|
The use of multiple B<-signer> options and the B<-resign> command were first
|
|
added in OpenSSL 1.0.0.
|
|
|
|
The B<keyopt> option was first added in OpenSSL 1.0.2.
|
|
|
|
Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.0.2.
|
|
|
|
The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
|
|
to OpenSSL 1.0.2.
|
|
|
|
The -no_alt_chains options was first added to OpenSSL 1.0.2b.
|
|
|
|
=cut
|