doc/man3/CMS_add1_signer.pod - third_party/openssl - Git at Google

 =pod

 =head1 NAME

 CMS_add1_signer, CMS_SignerInfo_sign - add a signer to a CMS_ContentInfo signed data structure

 =head1 SYNOPSIS

  #include <openssl/cms.h>

  CMS_SignerInfo *CMS_add1_signer(CMS_ContentInfo *cms, X509 *signcert,
                                  EVP_PKEY *pkey, const EVP_MD *md,
                                  unsigned int flags);

  int CMS_SignerInfo_sign(CMS_SignerInfo *si);

 =head1 DESCRIPTION

 CMS_add1_signer() adds a signer with certificate B<signcert> and private
 key B<pkey> using message digest B<md> to CMS_ContentInfo SignedData
 structure B<cms>.

 The CMS_ContentInfo structure should be obtained from an initial call to
 CMS_sign() with the flag B<CMS_PARTIAL> set or in the case or re-signing a
 valid CMS_ContentInfo SignedData structure.

 If the B<md> parameter is B<NULL> then the default digest for the public
 key algorithm will be used.

 Unless the B<CMS_REUSE_DIGEST> flag is set the returned CMS_ContentInfo
 structure is not complete and must be finalized either by streaming (if
 applicable) or a call to CMS_final().

 The CMS_SignerInfo_sign() function will explicitly sign a CMS_SignerInfo
 structure, its main use is when B<CMS_REUSE_DIGEST> and B<CMS_PARTIAL> flags
 are both set.

 =head1 NOTES

 The main purpose of CMS_add1_signer() is to provide finer control
 over a CMS signed data structure where the simpler CMS_sign() function defaults
 are not appropriate. For example if multiple signers or non default digest
 algorithms are needed. New attributes can also be added using the returned
 CMS_SignerInfo structure and the CMS attribute utility functions or the
 CMS signed receipt request functions.

 Any of the following flags (ored together) can be passed in the B<flags>
 parameter.

 If B<CMS_REUSE_DIGEST> is set then an attempt is made to copy the content
 digest value from the CMS_ContentInfo structure: to add a signer to an existing
 structure.  An error occurs if a matching digest value cannot be found to copy.
 The returned CMS_ContentInfo structure will be valid and finalized when this
 flag is set.

 If B<CMS_PARTIAL> is set in addition to B<CMS_REUSE_DIGEST> then the
 CMS_SignerInfo structure will not be finalized so additional attributes
 can be added. In this case an explicit call to CMS_SignerInfo_sign() is
 needed to finalize it.

 If B<CMS_NOCERTS> is set the signer's certificate will not be included in the
 CMS_ContentInfo structure, the signer's certificate must still be supplied in
 the B<signcert> parameter though. This can reduce the size of the signature if
 the signers certificate can be obtained by other means: for example a
 previously signed message.

 The SignedData structure includes several CMS signedAttributes including the
 signing time, the CMS content type and the supported list of ciphers in an
 SMIMECapabilities attribute. If B<CMS_NOATTR> is set then no signedAttributes
 will be used. If B<CMS_NOSMIMECAP> is set then just the SMIMECapabilities are
 omitted.

 OpenSSL will by default identify signing certificates using issuer name
 and serial number. If B<CMS_USE_KEYID> is set it will use the subject key
 identifier value instead. An error occurs if the signing certificate does not
 have a subject key identifier extension.

 If present the SMIMECapabilities attribute indicates support for the following
 algorithms in preference order: 256 bit AES, Gost R3411-94, Gost 28147-89, 192
 bit AES, 128 bit AES, triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2.
 If any of these algorithms is not available then it will not be included: for example the GOST algorithms will not be included if the GOST ENGINE is
 not loaded.

 CMS_add1_signer() returns an internal pointer to the CMS_SignerInfo
 structure just added, this can be used to set additional attributes
 before it is finalized.

 =head1 RETURN VALUES

 CMS_add1_signer() returns an internal pointer to the CMS_SignerInfo
 structure just added or NULL if an error occurs.

 =head1 SEE ALSO

 L<ERR_get_error(3)>, L<CMS_sign(3)>,
 L<CMS_final(3)>,

 =head1 COPYRIGHT

 Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.

 Licensed under the Apache License 2.0 (the "License").  You may not use
 this file except in compliance with the License.  You can obtain a copy
 in the file LICENSE in the source distribution or at
 L<https://www.openssl.org/source/license.html>.

 =cut
	=pod

	=head1 NAME

	CMS_add1_signer, CMS_SignerInfo_sign - add a signer to a CMS_ContentInfo signed data structure

	=head1 SYNOPSIS

	#include <openssl/cms.h>

	CMS_SignerInfo CMS_add1_signer(CMS_ContentInfo cms, X509 *signcert,
	EVP_PKEY pkey, const EVP_MD md,
	unsigned int flags);

	int CMS_SignerInfo_sign(CMS_SignerInfo *si);

	=head1 DESCRIPTION

	CMS_add1_signer() adds a signer with certificate B<signcert> and private
	key B<pkey> using message digest B<md> to CMS_ContentInfo SignedData
	structure B<cms>.

	The CMS_ContentInfo structure should be obtained from an initial call to
	CMS_sign() with the flag B<CMS_PARTIAL> set or in the case or re-signing a
	valid CMS_ContentInfo SignedData structure.

	If the B<md> parameter is B<NULL> then the default digest for the public
	key algorithm will be used.

	Unless the B<CMS_REUSE_DIGEST> flag is set the returned CMS_ContentInfo
	structure is not complete and must be finalized either by streaming (if
	applicable) or a call to CMS_final().

	The CMS_SignerInfo_sign() function will explicitly sign a CMS_SignerInfo
	structure, its main use is when B<CMS_REUSE_DIGEST> and B<CMS_PARTIAL> flags
	are both set.

	=head1 NOTES

	The main purpose of CMS_add1_signer() is to provide finer control
	over a CMS signed data structure where the simpler CMS_sign() function defaults
	are not appropriate. For example if multiple signers or non default digest
	algorithms are needed. New attributes can also be added using the returned
	CMS_SignerInfo structure and the CMS attribute utility functions or the
	CMS signed receipt request functions.

	Any of the following flags (ored together) can be passed in the B<flags>
	parameter.

	If B<CMS_REUSE_DIGEST> is set then an attempt is made to copy the content
	digest value from the CMS_ContentInfo structure: to add a signer to an existing
	structure. An error occurs if a matching digest value cannot be found to copy.
	The returned CMS_ContentInfo structure will be valid and finalized when this
	flag is set.

	If B<CMS_PARTIAL> is set in addition to B<CMS_REUSE_DIGEST> then the
	CMS_SignerInfo structure will not be finalized so additional attributes
	can be added. In this case an explicit call to CMS_SignerInfo_sign() is
	needed to finalize it.

	If B<CMS_NOCERTS> is set the signer's certificate will not be included in the
	CMS_ContentInfo structure, the signer's certificate must still be supplied in
	the B<signcert> parameter though. This can reduce the size of the signature if
	the signers certificate can be obtained by other means: for example a
	previously signed message.

	The SignedData structure includes several CMS signedAttributes including the
	signing time, the CMS content type and the supported list of ciphers in an
	SMIMECapabilities attribute. If B<CMS_NOATTR> is set then no signedAttributes
	will be used. If B<CMS_NOSMIMECAP> is set then just the SMIMECapabilities are
	omitted.

	OpenSSL will by default identify signing certificates using issuer name
	and serial number. If B<CMS_USE_KEYID> is set it will use the subject key
	identifier value instead. An error occurs if the signing certificate does not
	have a subject key identifier extension.

	If present the SMIMECapabilities attribute indicates support for the following
	algorithms in preference order: 256 bit AES, Gost R3411-94, Gost 28147-89, 192
	bit AES, 128 bit AES, triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2.
	If any of these algorithms is not available then it will not be included: for example the GOST algorithms will not be included if the GOST ENGINE is
	not loaded.

	CMS_add1_signer() returns an internal pointer to the CMS_SignerInfo
	structure just added, this can be used to set additional attributes
	before it is finalized.

	=head1 RETURN VALUES

	CMS_add1_signer() returns an internal pointer to the CMS_SignerInfo
	structure just added or NULL if an error occurs.

	=head1 SEE ALSO

	L<ERR_get_error(3)>, L<CMS_sign(3)>,
	L<CMS_final(3)>,

	=head1 COPYRIGHT

	Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.

	Licensed under the Apache License 2.0 (the "License"). You may not use
	this file except in compliance with the License. You can obtain a copy
	in the file LICENSE in the source distribution or at
	L<https://www.openssl.org/source/license.html>.

	=cut