NAME

       CMS_add1_recipient, CMS_add1_recipient_cert, CMS_add0_recipient_key - add recipients to a
       CMS enveloped data structure

SYNOPSIS

        #include <openssl/cms.h>

        CMS_RecipientInfo *CMS_add1_recipient(CMS_ContentInfo *cms, X509 *recip,
                                              EVP_PKEY *originatorPrivKey,
                                              X509 *originator, unsigned int flags);

        CMS_RecipientInfo *CMS_add1_recipient_cert(CMS_ContentInfo *cms,
                                                   X509 *recip, unsigned int flags);

        CMS_RecipientInfo *CMS_add0_recipient_key(CMS_ContentInfo *cms, int nid,
                                                  unsigned char *key, size_t keylen,
                                                  unsigned char *id, size_t idlen,
                                                  ASN1_GENERALIZEDTIME *date,
                                                  ASN1_OBJECT *otherTypeId,
                                                  ASN1_TYPE *otherType);

DESCRIPTION

       CMS_add1_recipient() adds recipient recip and provides the originator pkey
       originatorPrivKey and originator certificate originator to CMS_ContentInfo.  The
       originator-related fields are relevant only in case when the keyAgreement method of
       providing of the shared key is in use.

       CMS_add1_recipient_cert() adds recipient recip to CMS_ContentInfo enveloped data structure
       cms as a KeyTransRecipientInfo structure.

       CMS_add0_recipient_key() adds symmetric key key of length keylen using wrapping algorithm
       nid, identifier id of length idlen and optional values date, otherTypeId and otherType to
       CMS_ContentInfo enveloped data structure cms as a KEKRecipientInfo structure.

       The CMS_ContentInfo structure should be obtained from an initial call to CMS_encrypt()
       with the flag CMS_PARTIAL set.

NOTES

       The main purpose of this function is to provide finer control over a CMS enveloped data
       structure where the simpler CMS_encrypt() function defaults are not appropriate. For
       example if one or more KEKRecipientInfo structures need to be added. New attributes can
       also be added using the returned CMS_RecipientInfo structure and the CMS attribute utility
       functions.

       OpenSSL will by default identify recipient certificates using issuer name and serial
       number. If 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.

       Currently only AES based key wrapping algorithms are supported for nid, specifically:
       NID_id_aes128_wrap, NID_id_aes192_wrap and NID_id_aes256_wrap.  If nid is set to NID_undef
       then an AES wrap algorithm will be used consistent with keylen.

RETURN VALUES

       CMS_add1_recipient_cert() and CMS_add0_recipient_key() return an internal pointer to the
       CMS_RecipientInfo structure just added or NULL if an error occurs.

SEE ALSO

       ERR_get_error(3), CMS_decrypt(3), CMS_final(3),

HISTORY

       CMS_add1_recipient_cert and CMS_add0_recipient_key were added in OpenSSL 3.0.

COPYRIGHT

       Copyright 2008-2021 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 <https://www.openssl.org/source/license.html>.