doc/man3/PKCS7_sign.pod - third_party/openssl - Git at Google

 =pod

 =head1 NAME

 PKCS7_sign_ex, PKCS7_sign
 - create a PKCS#7 signedData structure

 =head1 SYNOPSIS

  #include <openssl/pkcs7.h>

  PKCS7 *PKCS7_sign_ex(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs,
                       BIO *data, int flags, OSSL_LIB_CTX *libctx,
                       const char *propq);
  PKCS7 *PKCS7_sign(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs,
                    BIO *data, int flags);

 =head1 DESCRIPTION

 PKCS7_sign_ex() creates and returns a PKCS#7 signedData structure.
 I<igncert> is the certificate to sign with, Ipkey> is the corresponding
 private key. I<certs> is an optional additional set of certificates to include
 in the PKCS#7 structure (for example any intermediate CAs in the chain). The
 library context I<libctx> and property query I<propq> are used when
 retrieving algorithms from providers.

 The data to be signed is read from BIO B<data>.

 B<flags> is an optional set of flags.

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

 Many S/MIME clients expect the signed content to include valid MIME headers. If
 the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended
 to the data.

 If B<PKCS7_NOCERTS> is set the signer's certificate will not be included in the
 PKCS7 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 data being signed is included in the PKCS7 structure, unless
 B<PKCS7_DETACHED> is set in which case it is omitted. This is used for PKCS7
 detached signatures which are used in S/MIME plaintext signed messages for
 example.

 Normally the supplied content is translated into MIME canonical format (as
 required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation
 occurs. This option should be used if the supplied data is in binary format
 otherwise the translation will corrupt it.

 The signedData structure includes several PKCS#7 authenticatedAttributes
 including the signing time, the PKCS#7 content type and the supported list of
 ciphers in an SMIMECapabilities attribute. If B<PKCS7_NOATTR> is set then no
 authenticatedAttributes will be used. If B<PKCS7_NOSMIMECAP> is set then just
 the SMIMECapabilities are omitted.

 If present the SMIMECapabilities attribute indicates support for the following
 algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any of
 these algorithms is disabled then it will not be included.

 If the flags B<PKCS7_STREAM> is set then the returned B<PKCS7> structure is
 just initialized ready to perform the signing operation. The signing is however
 B<not> performed and the data to be signed is not read from the B<data>
 parameter. Signing is deferred until after the data has been written. In this
 way data can be signed in a single pass.

 If the B<PKCS7_PARTIAL> flag is set a partial B<PKCS7> structure is output to
 which additional signers and capabilities can be added before finalization.

 If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not>
 complete and outputting its contents via a function that does not properly
 finalize the B<PKCS7> structure will give unpredictable results.

 Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(),
 PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization
 can be performed by obtaining the streaming ASN1 B<BIO> directly using
 BIO_new_PKCS7().

 If a signer is specified it will use the default digest for the signing
 algorithm. This is B<SHA1> for both RSA and DSA keys.

 The B<certs>, B<signcert> and B<pkey> parameters can all be
 B<NULL> if the B<PKCS7_PARTIAL> flag is set. One or more signers can be added
 using the function PKCS7_sign_add_signer(). PKCS7_final() must also be
 called to finalize the structure if streaming is not enabled. Alternative
 signing digests can also be specified using this method.

 If B<signcert> and B<pkey> are NULL then a certificates only
 PKCS#7 structure is output.

 In versions of OpenSSL before 1.0.0 the B<signcert> and B<pkey> parameters must
 B<NOT> be NULL.

 PKCS7_sign() is similar to PKCS7_sign_ex() but uses default values of
 NULL for the library context I<libctx> and the property query I<propq>.

 =head1 BUGS

 Some advanced attributes such as counter signatures are not supported.

 =head1 RETURN VALUES

 PKCS7_sign_ex() and PKCS7_sign() return either a valid PKCS7 structure
 or NULL if an error occurred.  The error can be obtained from ERR_get_error(3).

 =head1 SEE ALSO

 L<ERR_get_error(3)>, L<PKCS7_verify(3)>

 =head1 HISTORY

 The function PKCS7_sign_ex() was added in OpenSSL 3.0.

 The B<PKCS7_PARTIAL> flag, and the ability for B<certs>, B<signcert>,
 and B<pkey> parameters to be B<NULL> were added in OpenSSL 1.0.0.

 The B<PKCS7_STREAM> flag was added in OpenSSL 1.0.0.

 =head1 COPYRIGHT

 Copyright 2002-2020 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

	PKCS7_sign_ex, PKCS7_sign
	- create a PKCS#7 signedData structure

	=head1 SYNOPSIS

	#include <openssl/pkcs7.h>

	PKCS7 PKCS7_sign_ex(X509 signcert, EVP_PKEY pkey, STACK_OF(X509) certs,
	BIO data, int flags, OSSL_LIB_CTX libctx,
	const char *propq);
	PKCS7 PKCS7_sign(X509 signcert, EVP_PKEY pkey, STACK_OF(X509) certs,
	BIO *data, int flags);

	=head1 DESCRIPTION

	PKCS7_sign_ex() creates and returns a PKCS#7 signedData structure.
	I<igncert> is the certificate to sign with, Ipkey> is the corresponding
	private key. I<certs> is an optional additional set of certificates to include
	in the PKCS#7 structure (for example any intermediate CAs in the chain). The
	library context I<libctx> and property query I<propq> are used when
	retrieving algorithms from providers.

	The data to be signed is read from BIO B<data>.

	B<flags> is an optional set of flags.

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

	Many S/MIME clients expect the signed content to include valid MIME headers. If
	the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended
	to the data.

	If B<PKCS7_NOCERTS> is set the signer's certificate will not be included in the
	PKCS7 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 data being signed is included in the PKCS7 structure, unless
	B<PKCS7_DETACHED> is set in which case it is omitted. This is used for PKCS7
	detached signatures which are used in S/MIME plaintext signed messages for
	example.

	Normally the supplied content is translated into MIME canonical format (as
	required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation
	occurs. This option should be used if the supplied data is in binary format
	otherwise the translation will corrupt it.

	The signedData structure includes several PKCS#7 authenticatedAttributes
	including the signing time, the PKCS#7 content type and the supported list of
	ciphers in an SMIMECapabilities attribute. If B<PKCS7_NOATTR> is set then no
	authenticatedAttributes will be used. If B<PKCS7_NOSMIMECAP> is set then just
	the SMIMECapabilities are omitted.

	If present the SMIMECapabilities attribute indicates support for the following
	algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any of
	these algorithms is disabled then it will not be included.

	If the flags B<PKCS7_STREAM> is set then the returned B<PKCS7> structure is
	just initialized ready to perform the signing operation. The signing is however
	B<not> performed and the data to be signed is not read from the B<data>
	parameter. Signing is deferred until after the data has been written. In this
	way data can be signed in a single pass.

	If the B<PKCS7_PARTIAL> flag is set a partial B<PKCS7> structure is output to
	which additional signers and capabilities can be added before finalization.

	If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not>
	complete and outputting its contents via a function that does not properly
	finalize the B<PKCS7> structure will give unpredictable results.

	Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(),
	PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization
	can be performed by obtaining the streaming ASN1 B<BIO> directly using
	BIO_new_PKCS7().

	If a signer is specified it will use the default digest for the signing
	algorithm. This is B<SHA1> for both RSA and DSA keys.

	The B<certs>, B<signcert> and B<pkey> parameters can all be
	B<NULL> if the B<PKCS7_PARTIAL> flag is set. One or more signers can be added
	using the function PKCS7_sign_add_signer(). PKCS7_final() must also be
	called to finalize the structure if streaming is not enabled. Alternative
	signing digests can also be specified using this method.

	If B<signcert> and B<pkey> are NULL then a certificates only
	PKCS#7 structure is output.

	In versions of OpenSSL before 1.0.0 the B<signcert> and B<pkey> parameters must
	B<NOT> be NULL.

	PKCS7_sign() is similar to PKCS7_sign_ex() but uses default values of
	NULL for the library context I<libctx> and the property query I<propq>.

	=head1 BUGS

	Some advanced attributes such as counter signatures are not supported.

	=head1 RETURN VALUES

	PKCS7_sign_ex() and PKCS7_sign() return either a valid PKCS7 structure
	or NULL if an error occurred. The error can be obtained from ERR_get_error(3).

	=head1 SEE ALSO

	L<ERR_get_error(3)>, L<PKCS7_verify(3)>

	=head1 HISTORY

	The function PKCS7_sign_ex() was added in OpenSSL 3.0.

	The B<PKCS7_PARTIAL> flag, and the ability for B<certs>, B<signcert>,
	and B<pkey> parameters to be B<NULL> were added in OpenSSL 1.0.0.

	The B<PKCS7_STREAM> flag was added in OpenSSL 1.0.0.

	=head1 COPYRIGHT

	Copyright 2002-2020 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