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

 =pod

 =head1 NAME

 CMS_encrypt_ex, CMS_encrypt - create a CMS envelopedData structure

 =head1 SYNOPSIS

  #include <openssl/cms.h>

  CMS_ContentInfo *CMS_encrypt_ex(STACK_OF(X509) *certs, BIO *in,
                                  const EVP_CIPHER *cipher, unsigned int flags,
                                  OSSL_LIB_CTX *libctx, const char *propq);
  CMS_ContentInfo *CMS_encrypt(STACK_OF(X509) *certs, BIO *in,
                               const EVP_CIPHER *cipher, unsigned int flags);

 =head1 DESCRIPTION

 CMS_encrypt_ex() creates and returns a CMS EnvelopedData or
 AuthEnvelopedData structure. I<certs> is a list of recipient certificates.
 I<in> is the content to be encrypted. I<cipher> is the symmetric cipher to use.
 I<flags> is an optional set of flags. The library context I<libctx> and the
 property query I<propq> are used internally when retrieving algorithms from
 providers.

 Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
 function.

 EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use
 because most clients will support it.

 The algorithm passed in the B<cipher> parameter must support ASN1 encoding of
 its parameters. If the cipher mode is GCM, then an AuthEnvelopedData structure
 containing MAC is used. Otherwise an EnvelopedData structure is used. Currently
 the AES variants with GCM mode are the only supported AEAD algorithms.

 Many browsers implement a "sign and encrypt" option which is simply an S/MIME
 envelopedData containing an S/MIME signed message. This can be readily produced
 by storing the S/MIME signed message in a memory BIO and passing it to
 CMS_encrypt().

 The following flags can be passed in the B<flags> parameter.

 If the B<CMS_TEXT> flag is set MIME headers for type B<text/plain> are
 prepended to the data.

 Normally the supplied content is translated into MIME canonical format (as
 required by the S/MIME specifications) if B<CMS_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. If B<CMS_BINARY> is set then
 B<CMS_TEXT> is ignored.

 OpenSSL will by default identify recipient 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 all recipient certificates do not
 have a subject key identifier extension.

 If the B<CMS_STREAM> flag is set a partial B<CMS_ContentInfo> structure is
 returned suitable for streaming I/O: no data is read from the BIO B<in>.

 If the B<CMS_PARTIAL> flag is set a partial B<CMS_ContentInfo> structure is
 returned to which additional recipients and attributes can be added before
 finalization.

 The data being encrypted is included in the CMS_ContentInfo structure, unless
 B<CMS_DETACHED> is set in which case it is omitted. This is rarely used in
 practice and is not supported by SMIME_write_CMS().

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

 Several functions including SMIME_write_CMS(), i2d_CMS_bio_stream(),
 PEM_write_bio_CMS_stream() finalize the structure. Alternatively finalization
 can be performed by obtaining the streaming ASN1 B<BIO> directly using
 BIO_new_CMS().

 The recipients specified in B<certs> use a CMS KeyTransRecipientInfo info
 structure. KEKRecipientInfo is also supported using the flag B<CMS_PARTIAL>
 and CMS_add0_recipient_key().

 The parameter B<certs> may be NULL if B<CMS_PARTIAL> is set and recipients
 added later using CMS_add1_recipient_cert() or CMS_add0_recipient_key().

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

 =head1 RETURN VALUES

 CMS_encrypt_ex() and CMS_encrypt() return either a CMS_ContentInfo
 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<CMS_decrypt(3)>

 =head1 HISTORY

 The function CMS_encrypt_ex() was added in OpenSSL 3.0.

 The B<CMS_STREAM> flag was first supported in OpenSSL 1.0.0.

 =head1 COPYRIGHT

 Copyright 2008-2020 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

	CMS_encrypt_ex, CMS_encrypt - create a CMS envelopedData structure

	=head1 SYNOPSIS

	#include <openssl/cms.h>

	CMS_ContentInfo CMS_encrypt_ex(STACK_OF(X509) certs, BIO *in,
	const EVP_CIPHER *cipher, unsigned int flags,
	OSSL_LIB_CTX libctx, const char propq);
	CMS_ContentInfo CMS_encrypt(STACK_OF(X509) certs, BIO *in,
	const EVP_CIPHER *cipher, unsigned int flags);

	=head1 DESCRIPTION

	CMS_encrypt_ex() creates and returns a CMS EnvelopedData or
	AuthEnvelopedData structure. I<certs> is a list of recipient certificates.
	I<in> is the content to be encrypted. I<cipher> is the symmetric cipher to use.
	I<flags> is an optional set of flags. The library context I<libctx> and the
	property query I<propq> are used internally when retrieving algorithms from
	providers.

	Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
	function.

	EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use
	because most clients will support it.

	The algorithm passed in the B<cipher> parameter must support ASN1 encoding of
	its parameters. If the cipher mode is GCM, then an AuthEnvelopedData structure
	containing MAC is used. Otherwise an EnvelopedData structure is used. Currently
	the AES variants with GCM mode are the only supported AEAD algorithms.

	Many browsers implement a "sign and encrypt" option which is simply an S/MIME
	envelopedData containing an S/MIME signed message. This can be readily produced
	by storing the S/MIME signed message in a memory BIO and passing it to
	CMS_encrypt().

	The following flags can be passed in the B<flags> parameter.

	If the B<CMS_TEXT> flag is set MIME headers for type B<text/plain> are
	prepended to the data.

	Normally the supplied content is translated into MIME canonical format (as
	required by the S/MIME specifications) if B<CMS_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. If B<CMS_BINARY> is set then
	B<CMS_TEXT> is ignored.

	OpenSSL will by default identify recipient 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 all recipient certificates do not
	have a subject key identifier extension.

	If the B<CMS_STREAM> flag is set a partial B<CMS_ContentInfo> structure is
	returned suitable for streaming I/O: no data is read from the BIO B<in>.

	If the B<CMS_PARTIAL> flag is set a partial B<CMS_ContentInfo> structure is
	returned to which additional recipients and attributes can be added before
	finalization.

	The data being encrypted is included in the CMS_ContentInfo structure, unless
	B<CMS_DETACHED> is set in which case it is omitted. This is rarely used in
	practice and is not supported by SMIME_write_CMS().

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

	Several functions including SMIME_write_CMS(), i2d_CMS_bio_stream(),
	PEM_write_bio_CMS_stream() finalize the structure. Alternatively finalization
	can be performed by obtaining the streaming ASN1 B<BIO> directly using
	BIO_new_CMS().

	The recipients specified in B<certs> use a CMS KeyTransRecipientInfo info
	structure. KEKRecipientInfo is also supported using the flag B<CMS_PARTIAL>
	and CMS_add0_recipient_key().

	The parameter B<certs> may be NULL if B<CMS_PARTIAL> is set and recipients
	added later using CMS_add1_recipient_cert() or CMS_add0_recipient_key().

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

	=head1 RETURN VALUES

	CMS_encrypt_ex() and CMS_encrypt() return either a CMS_ContentInfo
	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<CMS_decrypt(3)>

	=head1 HISTORY

	The function CMS_encrypt_ex() was added in OpenSSL 3.0.

	The B<CMS_STREAM> flag was first supported in OpenSSL 1.0.0.

	=head1 COPYRIGHT

	Copyright 2008-2020 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