NAME

       CMS_SignerInfo_set1_signer_cert, CMS_get0_SignerInfos, CMS_SignerInfo_get0_signer_id,
       CMS_SignerInfo_get0_signature, CMS_SignerInfo_cert_cmp - CMS signedData signer functions

SYNOPSIS

        #include <openssl/cms.h>

        STACK_OF(CMS_SignerInfo) *CMS_get0_SignerInfos(CMS_ContentInfo *cms);

        int CMS_SignerInfo_get0_signer_id(CMS_SignerInfo *si, ASN1_OCTET_STRING **keyid,
                                          X509_NAME **issuer, ASN1_INTEGER **sno);
        ASN1_OCTET_STRING *CMS_SignerInfo_get0_signature(CMS_SignerInfo *si);
        int CMS_SignerInfo_cert_cmp(CMS_SignerInfo *si, X509 *cert);
        void CMS_SignerInfo_set1_signer_cert(CMS_SignerInfo *si, X509 *signer);

DESCRIPTION

       The function CMS_get0_SignerInfos() returns all the CMS_SignerInfo structures associated
       with a CMS signedData structure.

       CMS_SignerInfo_get0_signer_id() retrieves the certificate signer identifier associated
       with a specific CMS_SignerInfo structure si. Either the keyidentifier will be set in keyid
       or both issuer name and serial number in issuer and sno.

       CMS_SignerInfo_get0_signature() retrieves the signature associated with si in a pointer to
       an ASN1_OCTET_STRING structure. This pointer returned corresponds to the internal
       signature value if si so it may be read or modified.

       CMS_SignerInfo_cert_cmp() compares the certificate cert against the signer identifier si.
       It returns zero if the comparison is successful and non zero if not.

       CMS_SignerInfo_set1_signer_cert() sets the signers certificate of si to signer.

NOTES

       The main purpose of these functions is to enable an application to lookup signers
       certificates using any appropriate technique when the simpler method of CMS_verify() is
       not appropriate.

       In typical usage and application will retrieve all CMS_SignerInfo structures using
       CMS_get0_SignerInfo() and retrieve the identifier information using CMS. It will then
       obtain the signer certificate by some unspecified means (or return and error if it cannot
       be found) and set it using CMS_SignerInfo_set1_signer_cert().

       Once all signer certificates have been set CMS_verify() can be used.

       Although CMS_get0_SignerInfos() can return NULL if an error occurs or if there are no
       signers this is not a problem in practice because the only error which can occur is if the
       cms structure is not of type signedData due to application error.

RETURN VALUES

       CMS_get0_SignerInfos() returns all CMS_SignerInfo structures, or NULL there are no signers
       or an error occurs.

       CMS_SignerInfo_get0_signer_id() returns 1 for success and 0 for failure.

       CMS_SignerInfo_cert_cmp() returns 0 for a successful comparison and non zero otherwise.

       CMS_SignerInfo_set1_signer_cert() does not return a value.

       Any error can be obtained from ERR_get_error(3)

SEE ALSO

       ERR_get_error(3), CMS_verify(3)

COPYRIGHT

       Copyright 2008-2018 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>.