openssl/doc/crypto/CMS_get0_RecipientInfos.pod

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=pod
=head1 NAME
CMS_get0_RecipientInfos, CMS_RecipientInfo_type, CMS_RecipientInfo_ktri_get0_signer_id,CMS_RecipientInfo_ktri_cert_cmp, CMS_RecipientInfo_set0_pkey, CMS_RecipientInfo_kekri_get0_id, CMS_RecipientInfo_kekri_id_cmp, CMS_RecipientInfo_set0_key, CMS_RecipientInfo_decrypt, CMS_RecipientInfo_encrypt - CMS envelopedData RecipientInfo routines
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=head1 SYNOPSIS
#include <openssl/cms.h>
STACK_OF(CMS_RecipientInfo) *CMS_get0_RecipientInfos(CMS_ContentInfo *cms);
int CMS_RecipientInfo_type(CMS_RecipientInfo *ri);
int CMS_RecipientInfo_ktri_get0_signer_id(CMS_RecipientInfo *ri, ASN1_OCTET_STRING **keyid, X509_NAME **issuer, ASN1_INTEGER **sno);
int CMS_RecipientInfo_ktri_cert_cmp(CMS_RecipientInfo *ri, X509 *cert);
int CMS_RecipientInfo_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pkey);
int CMS_RecipientInfo_kekri_get0_id(CMS_RecipientInfo *ri, X509_ALGOR **palg, ASN1_OCTET_STRING **pid, ASN1_GENERALIZEDTIME **pdate, ASN1_OBJECT **potherid, ASN1_TYPE **pothertype);
int CMS_RecipientInfo_kekri_id_cmp(CMS_RecipientInfo *ri, const unsigned char *id, size_t idlen);
int CMS_RecipientInfo_set0_key(CMS_RecipientInfo *ri, unsigned char *key, size_t keylen);
int CMS_RecipientInfo_decrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri);
int CMS_RecipientInfo_encrypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri);
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=head1 DESCRIPTION
The function CMS_get0_RecipientInfos() returns all the CMS_RecipientInfo
structures associated with a CMS EnvelopedData structure.
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CMS_RecipientInfo_type() returns the type of CMS_RecipientInfo structure B<ri>.
It will currently return CMS_RECIPINFO_TRANS, CMS_RECIPINFO_AGREE,
CMS_RECIPINFO_KEK, CMS_RECIPINFO_PASS, or CMS_RECIPINFO_OTHER.
CMS_RecipientInfo_ktri_get0_signer_id() retrieves the certificate recipient
identifier associated with a specific CMS_RecipientInfo structure B<ri>, which
must be of type CMS_RECIPINFO_TRANS. Either the keyidentifier will be set in
B<keyid> or B<both> issuer name and serial number in B<issuer> and B<sno>.
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CMS_RecipientInfo_ktri_cert_cmp() compares the certificate B<cert> against the
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CMS_RecipientInfo structure B<ri>, which must be of type CMS_RECIPINFO_TRANS.
It returns zero if the comparison is successful and non zero if not.
CMS_RecipientInfo_set0_pkey() associates the private key B<pkey> with
the CMS_RecipientInfo structure B<ri>, which must be of type
CMS_RECIPINFO_TRANS.
CMS_RecipientInfo_kekri_get0_id() retrieves the key information from the
CMS_RecipientInfo structure B<ri> which must be of type CMS_RECIPINFO_KEK. Any
of the remaining parameters can be NULL if the application is not interested in
the value of a field. Where a field is optional and absent NULL will be written
to the corresponding parameter. The keyEncryptionAlgorithm field is written to
B<palg>, the B<keyIdentifier> field is written to B<pid>, the B<date> field if
present is written to B<pdate>, if the B<other> field is present the components
B<keyAttrId> and B<keyAttr> are written to parameters B<potherid> and
B<pothertype>.
CMS_RecipientInfo_kekri_id_cmp() compares the ID in the B<id> and B<idlen>
parameters against the B<keyIdentifier> CMS_RecipientInfo structure B<ri>,
which must be of type CMS_RECIPINFO_KEK. It returns zero if the comparison is
successful and non zero if not.
CMS_RecipientInfo_set0_key() associates the symmetric key B<key> of length
B<keylen> with the CMS_RecipientInfo structure B<ri>, which must be of type
CMS_RECIPINFO_KEK.
CMS_RecipientInfo_decrypt() attempts to decrypt CMS_RecipientInfo structure
B<ri> in structure B<cms>. A key must have been associated with the structure
first.
CMS_RecipientInfo_encrypt() attempts to encrypt CMS_RecipientInfo structure
B<ri> in structure B<cms>. A key must have been associated with the structure
first and the content encryption key must be available: for example by a
previous call to CMS_RecipientInfo_decrypt().
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=head1 NOTES
The main purpose of these functions is to enable an application to lookup
recipient keys using any appropriate technique when the simpler method
of CMS_decrypt() is not appropriate.
In typical usage and application will retrieve all CMS_RecipientInfo structures
using CMS_get0_RecipientInfos() and check the type of each using
CMS_RecpientInfo_type(). Depending on the type the CMS_RecipientInfo structure
can be ignored or its key identifier data retrieved using an appropriate
function. Then if the corresponding secret or private key can be obtained by
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any appropriate means it can then associated with the structure and
CMS_RecpientInfo_decrypt() called. If successful CMS_decrypt() can be called
with a NULL key to decrypt the enveloped content.
The CMS_RecipientInfo_encrypt() can be used to add a new recipient to an
existing enveloped data structure. Typically an application will first decrypt
an appropriate CMS_RecipientInfo structure to make the content encrypt key
available, it will then add a new recipient using a function such as
CMS_add1_recipient_cert() and finally encrypt the content encryption key
using CMS_RecipientInfo_encrypt().
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=head1 RETURN VALUES
CMS_get0_RecipientInfos() returns all CMS_RecipientInfo structures, or NULL if
an error occurs.
CMS_RecipientInfo_ktri_get0_signer_id(), CMS_RecipientInfo_set0_pkey(),
CMS_RecipientInfo_kekri_get0_id(), CMS_RecipientInfo_set0_key() and
CMS_RecipientInfo_decrypt() return 1 for success or 0 if an error occurs.
CMS_RecipientInfo_encrypt() return 1 for success or 0 if an error occurs.
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CMS_RecipientInfo_ktri_cert_cmp() and CMS_RecipientInfo_kekri_cmp() return 0
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for a successful comparison and non zero otherwise.
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Any error can be obtained from L<ERR_get_error(3)>.
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=head1 SEE ALSO
L<ERR_get_error(3)>, L<CMS_decrypt(3)>
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=cut