OSSL_ESS_CHECK_SIGNING_CERTS(3SSL)

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version 4.0.3 · 2 versions
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💖 OSSL_ESS_CHECK_SIGNING_CERTS(3SSL) 💖

bestie. sit down. we're doing OpenSSL's Enhanced Security Services (ESS) today and honestly? it's giving ✨signature-freshness✨

this is the OpenSSL family of manual pages, and this particular icon is your one-stop shop for OSSL_ESS_signing_cert_new_init, OSSL_ESS_signing_cert_v2_new_init, OSSL_ESS_check_signing_certs, and OSSL_ESS_check_signing_certs_ex — aka the Enhanced Security Services (ESS) functions. yes that's a lot of underscores. no we don't talk about it. 🎀

🌸 SYNOPSIS 🌸

like, here's the shape of it, no cap:

#include <openssl/ess.h>

ESS_SIGNING_CERT *OSSL_ESS_signing_cert_new_init(const X509 *signcert,
                                                 const STACK_OF(X509) *certs,
                                                 int set_issuer_serial);
ESS_SIGNING_CERT_V2 *OSSL_ESS_signing_cert_v2_new_init(const EVP_MD *hash_alg,
                                                       const X509 *signcert,
                                                       const
                                                       STACK_OF(X509) *certs,
                                                       int set_issuer_serial);
int OSSL_ESS_check_signing_certs(const ESS_SIGNING_CERT *ss,
                                 const ESS_SIGNING_CERT_V2 *ssv2,
                                 const STACK_OF(X509) *chain,
                                 int require_signing_cert);

int OSSL_ESS_check_signing_certs_ex(const ESS_SIGNING_CERT *ss,
                                    const ESS_SIGNING_CERT_V2 *ssv2,
                                    const STACK_OF(X509) *chain,
                                    OSSL_LIB_CTX *libctx,
                                    const char *propq,
                                    int require_signing_cert);

🦋 DESCRIPTION 🦋

OSSL_ESS_signing_cert_new_init() is the little builder bestie. it generates a brand new ESS_SIGNING_CERT structure that references the given signcert — plus any extra certs you hand it — using their SHA-1 fingerprints. and if set_issuer_serial is nonzero, then the issuer and serial number of signcert get tucked into the ESS_CERT_ID as the issuerSerial field too. oh and for all members of certs, the issuerSerial field is always included. periodt. 💅

OSSL_ESS_signing_cert_v2_new_init() is literally the same vibe as OSSL_ESS_signing_cert_new_init(), except it uses the hash_alg you pass in and generates an ESS_SIGNING_CERT_V2 structure with ESS_CERT_ID_V2 elements. glow-up version, same energy.

OSSL_ESS_check_signing_certs() does the vibe check: it checks whether the validation chain chain actually contains the certificates required by the identifiers given in ss and/or ssv2. housekeeping to know:

  • If require_signing_cert is nonzero, then ss or ssv2 must not be NULL. no exceptions.
  • If both ss and ssv2 are not NULL, they get evaluated independently.
  • The list of certificate identifiers in ss is of type ESS_CERT_ID, while the list in ssv2 is of type ESS_CERT_ID_V2.
  • As far as these lists are present, they must be nonempty.
  • The certificate identified by their first entry must be the first element of chain, i.e. the signer certificate.
  • Any further certificates referenced in the list must also be found in chain.
  • The matching is done using the given certificate hash algorithm and value.
  • On top of the checks required by RFCs 2624 and 5035: if the issuerSerial field is included in an ESSCertID or ESSCertIDv2, it must match the certificate issuer and serial number attributes.

OSSL_ESS_check_signing_certs_ex() functions identically to OSSL_ESS_check_signing_certs(), but it hands you extra parameters — libctx and propq — for users who wish to specify a nondefault library context and property query, for when the function fetches digests to validate the certs. it's the deluxe edition 🫶

🧚 NOTES 🧚

ESS has been defined in RFC 2634, which got updated in RFC 5035 (ESS version 2) to support hash algorithms other than SHA-1. iconic evolution honestly.

this is used for TSP (RFC 3161) and CAdES-BES (informational RFC 5126). iykyk.

⭐ RETURN VALUES ⭐

  • OSSL_ESS_signing_cert_new_init() and OSSL_ESS_signing_cert_v2_new_init() return a pointer to the new structure — or NULL on malloc failure 😭
  • OSSL_ESS_check_signing_certs() and OSSL_ESS_check_signing_certs_ex() return:
    • 1 on success 🎉
    • 0 if a required certificate cannot be found
    • -1 on other error 💀

🌈 SEE ALSO 🌈

👑 HISTORY 👑

  • OSSL_ESS_signing_cert_new_init(), OSSL_ESS_signing_cert_v2_new_init(), and OSSL_ESS_check_signing_certs() were added in OpenSSL 3.0.
  • OSSL_ESS_check_signing_certs_ex() was added in OpenSSL 4.0. new girl on the block 💖

Copyright 2021-2026 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>.

okay that's the whole page bestie, you ate that 🍓 go forth and verify some signing certs, mwah 💅

this has been the OpenSSL 4.0.3 edition of the manual, dated 2026-09-29 — and yes, OSSL_ESS_CHECK_SIGNING_CERTS(3SSL), that's a wrap 🎀✨

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