SCT_validate.3ssl man page

SCT_validate, SCT_LIST_validate, SCT_get_validation_status — checks Signed Certificate Timestamps (SCTs) are valid


 #include <openssl/ct.h>
 typedef enum {
 } sct_validation_status_t;
 int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx);
 int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx);
 sct_validation_status_t SCT_get_validation_status(const SCT *sct);


SCT_validate() will check that an SCT is valid and verify its signature. SCT_LIST_validate() performs the same checks on an entire stack of SCTs. The result of the validation checks can be obtained by passing the SCT to SCT_get_validation_status().

A CT_POLICY_EVAL_CTX must be provided that specifies:


The certificate the SCT was issued for.

Failure to provide the certificate will result in the validation status being SCT_VALIDATION_STATUS_UNVERIFIED.


The issuer of that certificate.

This is only required if the SCT was issued for a pre-certificate (see RFC 6962). If it is required but not provided, the validation status will be SCT_VALIDATION_STATUS_UNVERIFIED.


A CTLOG_STORE that contains the CT log that issued this SCT.

If the SCT was issued by a log that is not in this CTLOG_STORE, the validation status will be SCT_VALIDATION_STATUS_UNKNOWN_LOG.

If the SCT is of an unsupported version (only v1 is currently supported), the validation status will be SCT_VALIDATION_STATUS_UNKNOWN_VERSION.

If the SCT's signature is incorrect, the validation status will be SCT_VALIDATION_STATUS_INVALID. Otherwise, if all checks have passed, the validation status will be SCT_VALIDATION_STATUS_VALID.


A return value of 0 from SCT_LIST_validate() should not be interpreted as a failure. At a minimum, only one valid SCT may provide sufficient confidence that a certificate has been publicly logged.

Return Values

SCT_validate() returns a negative integer if an internal error occurs, 0 if the SCT fails validation, or 1 if the SCT passes validation.

SCT_LIST_validate() returns a negative integer if an internal error occurs, 0 if any of SCTs fails validation, or 1 if they all pass validation.

SCT_get_validation_status() returns the validation status of the SCT. If SCT_validate() or SCT_LIST_validate() have not been passed that SCT, the returned value will be SCT_VALIDATION_STATUS_NOT_SET.

See Also



These functions were added in OpenSSL 1.1.0.


2017-02-11 1.1.0d OpenSSL