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 OpenSSL license (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>.