[#OSSL_ESS_check_signing_certs]
= OSSL_ESS_check_signing_certs
:mrdocs:

Verify that `chain` satisfies ESS signing‐certificate identifiers in `ss` and/or `ssv2.`

== Synopsis

Declared in `<openssl/ess.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
OSSL_ESS_check_signing_certs(
    xref:ESS_SIGNING_CERT-09.adoc[ESS_SIGNING_CERT] const* ss,
    xref:ESS_SIGNING_CERT_V2.adoc[ESS_SIGNING_CERT_V2] const* ssv2,
    xref:stack_st_X509.adoc[stack_st_X509] const* chain,
    int require_signing_cert);
----

== Return Value

1 on success, 0 if a required certificate is missing, or ‐1 on other error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *ss*
| Optional ESS SigningCertificate (CertID) attribute, or NULL.
| *ssv2*
| Optional ESS SigningCertificateV2 (CertIDv2) attribute, or NULL.
| *chain*
| Certificate validation chain; the first entry must be the signer.
| *require_signing_cert*
| Nonzero to require that `ss` or `ssv2` is non‐NULL.
|===


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