479 lines
17 KiB
Groff
479 lines
17 KiB
Groff
.\" $NetBSD: openssl_smime.1,v 1.4 2001/04/12 10:45:50 itojun Exp $
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.\" Thu Apr 12 19:26:34 2001
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.\" ======================================================================
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.\"
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.IX Title "SMIME 1"
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.TH SMIME 1 "0.9.6a" "2001-04-12" "OpenSSL"
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.UC
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.SH "NAME"
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smime \- S/MIME utility
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.SH "LIBRARY"
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libcrypto, -lcrypto
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.SH "SYNOPSIS"
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.IX Header "SYNOPSIS"
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\&\fBopenssl\fR \fBsmime\fR
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[\fB\-encrypt\fR]
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[\fB\-decrypt\fR]
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[\fB\-sign\fR]
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[\fB\-verify\fR]
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[\fB\-pk7out\fR]
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[\fB\-des\fR]
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[\fB\-des3\fR]
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[\fB\-rc2\-40\fR]
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[\fB\-rc2\-64\fR]
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[\fB\-rc2\-128\fR]
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[\fB\-in file\fR]
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[\fB\-certfile file\fR]
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[\fB\-signer file\fR]
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[\fB\-recip file\fR]
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[\fB\-in file\fR]
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[\fB\-inform SMIME|PEM|DER\fR]
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[\fB\-passin arg\fR]
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[\fB\-inkey file\fR]
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[\fB\-out file\fR]
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[\fB\-outform SMIME|PEM|DER\fR]
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[\fB\-content file\fR]
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[\fB\-to addr\fR]
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[\fB\-from ad\fR]
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[\fB\-subject s\fR]
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[\fB\-text\fR]
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[\fB\-rand \f(BIfile\fB\|(s)\fR]
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[cert.pem]...
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.SH "DESCRIPTION"
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.IX Header "DESCRIPTION"
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The \fBsmime\fR command handles S/MIME mail. It can encrypt, decrypt, sign and
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verify S/MIME messages.
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.SH "COMMAND OPTIONS"
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.IX Header "COMMAND OPTIONS"
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There are five operation options that set the type of operation to be performed.
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The meaning of the other options varies according to the operation type.
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.Ip "\fB\-encrypt\fR" 4
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.IX Item "-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 \s-1MIME\s0 format.
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.Ip "\fB\-decrypt\fR" 4
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.IX Item "-decrypt"
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decrypt mail using the supplied certificate and private key. Expects an
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encrypted mail message in \s-1MIME\s0 format for the input file. The decrypted mail
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is written to the output file.
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.Ip "\fB\-sign\fR" 4
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.IX Item "-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 \s-1MIME\s0 format is written
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to the output file.
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.Ip "\fB\-verify\fR" 4
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.IX Item "-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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.Ip "\fB\-pk7out\fR" 4
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.IX Item "-pk7out"
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takes an input message and writes out a \s-1PEM\s0 encoded PKCS#7 structure.
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.Ip "\fB\-in filename\fR" 4
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.IX Item "-in filename"
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the input message to be encrypted or signed or the \s-1MIME\s0 message to
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be decrypted or verified.
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.Ip "\fB\-inform SMIME|PEM|DER\fR" 4
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.IX Item "-inform SMIME|PEM|DER"
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this specifies the input format for the PKCS#7 structure. The default
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is \fB\s-1SMIME\s0\fR which reads an S/MIME format message. \fB\s-1PEM\s0\fR and \fB\s-1DER\s0\fR
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format change this to expect \s-1PEM\s0 and \s-1DER\s0 format PKCS#7 structures
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instead. This currently only affects the input format of the PKCS#7
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structure, if no PKCS#7 structure is being input (for example with
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\&\fB\-encrypt\fR or \fB\-sign\fR) this option has no effect.
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.Ip "\fB\-out filename\fR" 4
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.IX Item "-out filename"
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the message text that has been decrypted or verified or the output \s-1MIME\s0
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format message that has been signed or verified.
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.Ip "\fB\-outform SMIME|PEM|DER\fR" 4
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.IX Item "-outform SMIME|PEM|DER"
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this specifies the output format for the PKCS#7 structure. The default
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is \fB\s-1SMIME\s0\fR which write an S/MIME format message. \fB\s-1PEM\s0\fR and \fB\s-1DER\s0\fR
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format change this to write \s-1PEM\s0 and \s-1DER\s0 format PKCS#7 structures
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instead. This currently only affects the output format of the PKCS#7
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structure, if no PKCS#7 structure is being output (for example with
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\&\fB\-verify\fR or \fB\-decrypt\fR) this option has no effect.
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.Ip "\fB\-content filename\fR" 4
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.IX Item "-content filename"
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This specifies a file containing the detached content, this is only
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useful with the \fB\-verify\fR command. This is only usable if the PKCS#7
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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 \s-1MIME\s0 content type.
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.Ip "\fB\-text\fR" 4
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.IX Item "-text"
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this option adds plain text (text/plain) \s-1MIME\s0 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 \s-1MIME\s0
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type text/plain then an error occurs.
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.Ip "\fB\-CAfile file\fR" 4
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.IX Item "-CAfile file"
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a file containing trusted \s-1CA\s0 certificates, only used with \fB\-verify\fR.
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.Ip "\fB\-CApath dir\fR" 4
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.IX Item "-CApath dir"
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a directory containing trusted \s-1CA\s0 certificates, only used with
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\&\fB\-verify\fR. This directory must be a standard certificate directory: that
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is a hash of each subject name (using \fBx509 \-hash\fR) should be linked
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to each certificate.
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.Ip "\fB\-des \-des3 \-rc2\-40 \-rc2\-64 \-rc2\-128\fR" 4
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.IX Item "-des -des3 -rc2-40 -rc2-64 -rc2-128"
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the encryption algorithm to use. \s-1DES\s0 (56 bits), triple \s-1DES\s0 (168 bits)
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or 40, 64 or 128 bit \s-1RC2\s0 respectively if not specified 40 bit \s-1RC2\s0 is
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used. Only used with \fB\-encrypt\fR.
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.Ip "\fB\-nointern\fR" 4
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.IX Item "-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 \fB\-certfile\fR option are used.
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The supplied certificates can still be used as untrusted CAs however.
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.Ip "\fB\-noverify\fR" 4
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.IX Item "-noverify"
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do not verify the signers certificate of a signed message.
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.Ip "\fB\-nochain\fR" 4
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.IX Item "-nochain"
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do not do chain verification of signers certificates: that is don't
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use the certificates in the signed message as untrusted CAs.
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.Ip "\fB\-nosigs\fR" 4
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.IX Item "-nosigs"
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don't try to verify the signatures on the message.
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.Ip "\fB\-nocerts\fR" 4
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.IX Item "-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 \fB\-certfile\fR option for example).
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.Ip "\fB\-noattr\fR" 4
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.IX Item "-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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.Ip "\fB\-binary\fR" 4
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.IX Item "-binary"
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normally the input message is converted to \*(L"canonical\*(R" format which is
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effectively using \s-1CR\s0 and \s-1LF\s0 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 \s-1MIME\s0 format.
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.Ip "\fB\-nodetach\fR" 4
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.IX Item "-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 \s-1MIME\s0 type multipart/signed is used.
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.Ip "\fB\-certfile file\fR" 4
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.IX Item "-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 \s-1PEM\s0 format.
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.Ip "\fB\-signer file\fR" 4
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.IX Item "-signer file"
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the signers certificate when signing a message. If a message is
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being verified then the signers certificates will be written to this
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file if the verification was successful.
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.Ip "\fB\-recip file\fR" 4
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.IX Item "-recip file"
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the recipients certificate when decrypting a message. This certificate
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must match one of the recipients of the message or an error occurs.
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.Ip "\fB\-inkey file\fR" 4
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.IX Item "-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 \fB\-recip\fR or \fB\-signer\fR file.
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.Ip "\fB\-passin arg\fR" 4
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.IX Item "-passin arg"
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the private key password source. For more information about the format of \fBarg\fR
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see the \fB\s-1PASS\s0 \s-1PHRASE\s0 \s-1ARGUMENTS\s0\fR section in openssl(1).
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.Ip "\fB\-rand \f(BIfile\fB\|(s)\fR" 4
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.IX Item "-rand file"
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a file or files containing random data used to seed the random number
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generator, or an \s-1EGD\s0 socket (see 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 \fB;\fR for MS-Windows, \fB,\fR for OpenVMS, and \fB:\fR for
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all others.
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.Ip "\fBcert.pem...\fR" 4
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.IX Item "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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.Ip "\fB\-to, \-from, \-subject\fR" 4
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.IX Item "-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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.SH "NOTES"
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.IX Header "NOTES"
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The \s-1MIME\s0 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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.PP
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The supplied message to be signed or encrypted must include the
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necessary \s-1MIME\s0 headers or many S/MIME clients wont display it
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properly (if at all). You can use the \fB\-text\fR option to automatically
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add plain text headers.
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.PP
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A \*(L"signed and encrypted\*(R" 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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.PP
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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 \*(L"in parallel\*(R" by signing an already signed message.
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.PP
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The options \fB\-encrypt\fR and \fB\-decrypt\fR reflect common usage in S/MIME
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clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
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encrypted data is used for other purposes.
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.SH "EXIT CODES"
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.IX Header "EXIT CODES"
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.Ip "0" 4
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the operation was completely successfully.
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.Ip "1" 4
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.IX Item "1"
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an error occurred parsing the command options.
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.Ip "2" 4
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.IX Item "2"
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one of the input files could not be read.
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.Ip "3" 4
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.IX Item "3"
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an error occurred creating the PKCS#7 file or when reading the \s-1MIME\s0
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message.
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.Ip "4" 4
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.IX Item "4"
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an error occurred decrypting or verifying the message.
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.Ip "5" 4
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.IX Item "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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.SH "EXAMPLES"
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.IX Header "EXAMPLES"
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Create a cleartext signed message:
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.PP
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.Vb 2
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\& openssl smime -sign -in message.txt -text -out mail.msg \e
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\& -signer mycert.pem
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.Ve
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Create and opaque signed message
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.PP
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.Vb 2
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\& openssl smime -sign -in message.txt -text -out mail.msg -nodetach \e
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\& -signer mycert.pem
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.Ve
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Create a signed message, include some additional certificates and
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read the private key from another file:
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.PP
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.Vb 2
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\& openssl smime -sign -in in.txt -text -out mail.msg \e
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\& -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
|
|
.Ve
|
|
Send a signed message under Unix directly to sendmail, including headers:
|
|
.PP
|
|
.Vb 3
|
|
\& openssl smime -sign -in in.txt -text -signer mycert.pem \e
|
|
\& -from steve@openssl.org -to someone@somewhere \e
|
|
\& -subject "Signed message" | sendmail someone@somewhere
|
|
.Ve
|
|
Verify a message and extract the signer's certificate if successful:
|
|
.PP
|
|
.Vb 1
|
|
\& openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
|
|
.Ve
|
|
Send encrypted mail using triple \s-1DES:\s0
|
|
.PP
|
|
.Vb 3
|
|
\& openssl smime -encrypt -in in.txt -from steve@openssl.org \e
|
|
\& -to someone@somewhere -subject "Encrypted message" \e
|
|
\& -des3 user.pem -out mail.msg
|
|
.Ve
|
|
Sign and encrypt mail:
|
|
.PP
|
|
.Vb 4
|
|
\& openssl smime -sign -in ml.txt -signer my.pem -text \e
|
|
\& | openssl smime -encrypt -out mail.msg \e
|
|
\& -from steve@openssl.org -to someone@somewhere \e
|
|
\& -subject "Signed and Encrypted message" -des3 user.pem
|
|
.Ve
|
|
Note: the encryption command does not include the \fB\-text\fR option because the message
|
|
being encrypted already has \s-1MIME\s0 headers.
|
|
.PP
|
|
Decrypt mail:
|
|
.PP
|
|
.Vb 1
|
|
\& openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
|
|
.Ve
|
|
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:
|
|
.PP
|
|
.Vb 2
|
|
\& -----BEGIN PKCS7----
|
|
\& -----END PKCS7----
|
|
.Ve
|
|
and using the command,
|
|
.PP
|
|
.Vb 1
|
|
\& openssl smime -verify -inform PEM -in signature.pem -content content.txt
|
|
.Ve
|
|
alternatively you can base64 decode the signature and use
|
|
.PP
|
|
.Vb 1
|
|
\& openssl smime -verify -inform DER -in signature.der -content content.txt
|
|
.Ve
|
|
.SH "BUGS"
|
|
.IX Header "BUGS"
|
|
The \s-1MIME\s0 parser isn't very clever: it seems to handle most messages that I've thrown
|
|
at it but it may choke on others.
|
|
.PP
|
|
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.
|
|
.PP
|
|
Ideally a database should be maintained of a certificates for each email address.
|
|
.PP
|
|
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.
|
|
.PP
|
|
No revocation checking is done on the signer's certificate.
|
|
.PP
|
|
The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
|
|
structures may cause parsing errors.
|