OCSP_CERT_TO_ID(3) | Library Functions Manual | OCSP_CERT_TO_ID(3)

# NAME

`OCSP_CERTID_new`, `OCSP_CERTID_free`, `OCSP_cert_to_id`, `OCSP_cert_id_new`, `OCSP_id_issuer_cmp`, `OCSP_id_cmp`, `OCSP_id_get0_info` — OCSP certificate ID utility functions

# SYNOPSIS

library “libcrypto”
`#include <openssl/ocsp.h>`

OCSP_CERTID *
`OCSP_CERTID_new`(void);

void
`OCSP_CERTID_free`(OCSP_CERTID *id);

OCSP_CERTID *
`OCSP_cert_to_id`(const EVP_MD *dgst, const X509 *subject, const X509 *issuer);

OCSP_CERTID *
`OCSP_cert_id_new`(const EVP_MD *dgst, const X509_NAME *issuerName, const ASN1_BIT_STRING *issuerKey, const ASN1_INTEGER *serialNumber);

int
`OCSP_id_issuer_cmp`(OCSP_CERTID *a, OCSP_CERTID *b);

int
`OCSP_id_cmp`(OCSP_CERTID *a, OCSP_CERTID *b);

int
`OCSP_id_get0_info`(ASN1_OCTET_STRING **piNameHash, ASN1_OBJECT **pmd, ASN1_OCTET_STRING **pikeyHash, ASN1_INTEGER **pserial, OCSP_CERTID *cid);

# DESCRIPTION

`OCSP_CERTID_new`() allocates and initializes an empty OCSP_CERTID object, representing an ASN.1 CertID structure defined in RFC 6960. It can store hashes of an issuer's distinguished name and public key together with a serial number of a certificate. It is used by the OCSP_ONEREQ object described in OCSP_ONEREQ_new(3) and by the OCSP_SINGLERESP object described in OCSP_SINGLERESP_new(3). `OCSP_CERTID_free`() frees id.

`OCSP_cert_to_id`() creates and returns a new OCSP_CERTID object using message digest dgst for certificate subject with issuer issuer. If dgst is `NULL` then SHA-1 is used.

`OCSP_cert_id_new`() creates and returns a new OCSP_CERTID using dgst and issuer name issuerName, issuer key hash issuerKey and serial number serialNumber.

`OCSP_id_issuer_cmp`() compares the hash algorithms, the hashed issuer distinguished names and the hashed public keys of OCSP_CERTID a and b.

`OCSP_id_cmp`() compares OCSP_CERTID a and b using `OCSP_id_issuer_cmp`() followed by a comparison of the certificate serial numbers with ASN1_INTEGER_cmp(3).

`OCSP_id_get0_info`() returns the issuer name hash, hash OID, issuer key hash and serial number contained in cid. If any of the values are not required, the corresponding parameter can be set to `NULL`. The values returned by `OCSP_id_get0_info`() are internal pointers and must not be freed up by an application: they will be freed when the corresponding OCSP_CERTID object is freed.

OCSP clients will typically only use `OCSP_cert_to_id`() or `OCSP_cert_id_new`(): the other functions are used by responder applications.

# RETURN VALUES

`OCSP_CERTID_new`(), `OCSP_cert_to_id`(), and `OCSP_cert_id_new`() return either a pointer to a valid OCSP_CERTID object or `NULL` if an error occurred.

`OCSP_id_cmp`() and `OCSP_id_issuer_cmp`() return 0 for a match or non-zero otherwise.

`OCSP_id_get0_info`() returns 1 for success or 0 for failure.

# SEE ALSO

ASN1_INTEGER_cmp(3), EVP_DigestInit(3), OCSP_request_add1_nonce(3), OCSP_REQUEST_new(3), OCSP_resp_find_status(3), OCSP_response_status(3), OCSP_sendreq_new(3), X509_get_issuer_name(3), X509_NAME_new(3), X509_ocspid_print(3)

# STANDARDS

RFC 6960: X.509 Internet Public Key Infrastructure Online Certificate Status Protocol, section 4: Details of the Protocol

# HISTORY

These functions first appeared in OpenSSL 0.9.7 and have been available since OpenBSD 3.2.

June 8, 2025 | Debian