| Index: openssl/doc/crypto/PKCS7_sign.pod
|
| ===================================================================
|
| --- openssl/doc/crypto/PKCS7_sign.pod (revision 105093)
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| +++ openssl/doc/crypto/PKCS7_sign.pod (working copy)
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| @@ -12,10 +12,10 @@
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|
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| =head1 DESCRIPTION
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|
|
| -PKCS7_sign() creates and returns a PKCS#7 signedData structure. B<signcert>
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| -is the certificate to sign with, B<pkey> is the corresponsding private key.
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| -B<certs> is an optional additional set of certificates to include in the
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| -PKCS#7 structure (for example any intermediate CAs in the chain).
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| +PKCS7_sign() creates and returns a PKCS#7 signedData structure. B<signcert> is
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| +the certificate to sign with, B<pkey> is the corresponsding private key.
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| +B<certs> is an optional additional set of certificates to include in the PKCS#7
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| +structure (for example any intermediate CAs in the chain).
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|
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| The data to be signed is read from BIO B<data>.
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|
|
| @@ -23,72 +23,83 @@
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|
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| =head1 NOTES
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|
|
| -Any of the following flags (ored together) can be passed in the B<flags> parameter.
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| +Any of the following flags (ored together) can be passed in the B<flags>
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| +parameter.
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|
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| Many S/MIME clients expect the signed content to include valid MIME headers. If
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| the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended
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| to the data.
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|
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| If B<PKCS7_NOCERTS> is set the signer's certificate will not be included in the
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| -PKCS7 structure, the signer's certificate must still be supplied in the B<signcert>
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| -parameter though. This can reduce the size of the signature if the signers certificate
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| -can be obtained by other means: for example a previously signed message.
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| +PKCS7 structure, the signer's certificate must still be supplied in the
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| +B<signcert> parameter though. This can reduce the size of the signature if the
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| +signers certificate can be obtained by other means: for example a previously
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| +signed message.
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|
|
| -The data being signed is included in the PKCS7 structure, unless B<PKCS7_DETACHED>
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| -is set in which case it is omitted. This is used for PKCS7 detached signatures
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| -which are used in S/MIME plaintext signed messages for example.
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| +The data being signed is included in the PKCS7 structure, unless
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| +B<PKCS7_DETACHED> is set in which case it is omitted. This is used for PKCS7
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| +detached signatures which are used in S/MIME plaintext signed messages for
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| +example.
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|
|
| -Normally the supplied content is translated into MIME canonical format (as required
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| -by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation occurs. This
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| -option should be used if the supplied data is in binary format otherwise the translation
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| -will corrupt it.
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| +Normally the supplied content is translated into MIME canonical format (as
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| +required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation
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| +occurs. This option should be used if the supplied data is in binary format
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| +otherwise the translation will corrupt it.
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|
|
| -The signedData structure includes several PKCS#7 autenticatedAttributes including
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| -the signing time, the PKCS#7 content type and the supported list of ciphers in
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| -an SMIMECapabilities attribute. If B<PKCS7_NOATTR> is set then no authenticatedAttributes
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| -will be used. If B<PKCS7_NOSMIMECAP> is set then just the SMIMECapabilities are
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| -omitted.
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| +The signedData structure includes several PKCS#7 autenticatedAttributes
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| +including the signing time, the PKCS#7 content type and the supported list of
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| +ciphers in an SMIMECapabilities attribute. If B<PKCS7_NOATTR> is set then no
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| +authenticatedAttributes will be used. If B<PKCS7_NOSMIMECAP> is set then just
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| +the SMIMECapabilities are omitted.
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|
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| If present the SMIMECapabilities attribute indicates support for the following
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| -algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any
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| -of these algorithms is disabled then it will not be included.
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| +algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any of
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| +these algorithms is disabled then it will not be included.
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|
|
| -If the flags B<PKCS7_PARTSIGN> is set then the returned B<PKCS7> structure
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| -is just initialized ready to perform the signing operation. The signing
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| -is however B<not> performed and the data to be signed is not read from
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| -the B<data> parameter. Signing is deferred until after the data has been
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| -written. In this way data can be signed in a single pass. Currently the
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| -flag B<PKCS7_DETACHED> B<must> also be set.
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| +If the flags B<PKCS7_STREAM> is set then the returned B<PKCS7> structure is
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| +just initialized ready to perform the signing operation. The signing is however
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| +B<not> performed and the data to be signed is not read from the B<data>
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| +parameter. Signing is deferred until after the data has been written. In this
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| +way data can be signed in a single pass.
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|
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| +If the B<PKCS7_PARTIAL> flag is set a partial B<PKCS7> structure is output to
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| +which additional signers and capabilities can be added before finalization.
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| +
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| +
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| =head1 NOTES
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|
|
| -Currently the flag B<PKCS7_PARTSIGN> is only supported for detached
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| -data. If this flag is set the returned B<PKCS7> structure is B<not>
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| -complete and outputting its contents via a function that does not
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| -properly finalize the B<PKCS7> structure will give unpredictable
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| -results.
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| +If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not>
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| +complete and outputting its contents via a function that does not properly
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| +finalize the B<PKCS7> structure will give unpredictable results.
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|
|
| -At present only the SMIME_write_PKCS7() function properly finalizes the
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| -structure.
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| +Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(),
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| +PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization
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| +can be performed by obtaining the streaming ASN1 B<BIO> directly using
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| +BIO_new_PKCS7().
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|
|
| -=head1 BUGS
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| +If a signer is specified it will use the default digest for the signing
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| +algorithm. This is B<SHA1> for both RSA and DSA keys.
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|
|
| -PKCS7_sign() is somewhat limited. It does not support multiple signers, some
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| -advanced attributes such as counter signatures are not supported.
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| +In OpenSSL 1.0.0 the B<certs>, B<signcert> and B<pkey> parameters can all be
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| +B<NULL> if the B<PKCS7_PARTIAL> flag is set. One or more signers can be added
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| +using the function B<PKCS7_sign_add_signer()>. B<PKCS7_final()> must also be
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| +called to finalize the structure if streaming is not enabled. Alternative
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| +signing digests can also be specified using this method.
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|
|
| -The SHA1 digest algorithm is currently always used.
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| +In OpenSSL 1.0.0 if B<signcert> and B<pkey> are NULL then a certificates only
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| +PKCS#7 structure is output.
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|
|
| -When the signed data is not detached it will be stored in memory within the
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| -B<PKCS7> structure. This effectively limits the size of messages which can be
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| -signed due to memory restraints. There should be a way to sign data without
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| -having to hold it all in memory, this would however require fairly major
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| -revisions of the OpenSSL ASN1 code.
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| +In versions of OpenSSL before 1.0.0 the B<signcert> and B<pkey> parameters must
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| +B<NOT> be NULL.
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|
|
| +=head1 BUGS
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|
|
| +Some advanced attributes such as counter signatures are not supported.
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| +
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| =head1 RETURN VALUES
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|
|
| -PKCS7_sign() returns either a valid PKCS7 structure or NULL if an error occurred.
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| -The error can be obtained from ERR_get_error(3).
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| +PKCS7_sign() returns either a valid PKCS7 structure or NULL if an error
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| +occurred. The error can be obtained from ERR_get_error(3).
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|
|
| =head1 SEE ALSO
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|
|
| @@ -98,6 +109,8 @@
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|
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| PKCS7_sign() was added to OpenSSL 0.9.5
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|
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| -The B<PKCS7_PARTSIGN> flag was added in OpenSSL 0.9.8
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| +The B<PKCS7_PARTIAL> flag was added in OpenSSL 1.0.0
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|
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| +The B<PKCS7_STREAM> flag was added in OpenSSL 1.0.0
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| +
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| =cut
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|
|