- NAME
- SYNOPSIS
- DESCRIPTION
- BUGS
- RETURN VALUES
- SEE ALSO
- HISTORY
- COPYRIGHT

# NAME

X509_check_certificate_times, X509_time_adj, X509_time_adj_ex, X509_gmtime_adj, X509_cmp_time, X509_cmp_current_time, X509_cmp_timeframe - X509 time functions

# SYNOPSIS

    int X509_check_certificate_times(const X509_VERIFY_PARAM *vpm, const X509 *x,
                                     int *error);
    ASN1_TIME *X509_time_adj(ASN1_TIME *asn1_time, long offset_sec,
                             const time_t *in_tm);
    ASN1_TIME *X509_time_adj_ex(ASN1_TIME *asn1_time, int offset_day, long
                                offset_sec, const time_t *in_tm);
    ASN1_TIME *X509_gmtime_adj(ASN1_TIME *asn1_time, long offset_sec);

The following functions have been deprecated since OpenSSL 4.0, and can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):

    int X509_cmp_time(const ASN1_TIME *asn1_time, const time_t *in_tm);
    int X509_cmp_current_time(const ASN1_TIME *asn1_time);
    int X509_cmp_timeframe(const X509_VERIFY_PARAM *vpm,
                           const ASN1_TIME *start, const ASN1_TIME *end);

# DESCRIPTION

X509_check_certificate_times() compares the notBefore and notAfter times in certificate x to check the certificate for temporal validity. The time used for the check will be the current system time, unless The the reference time included in the verification parameter vpm is non NULL and vpm has the flag X509_V_FLAG_USE_CHECK_TIME set.

The notBefore and notAfter times in the certificate will be accepted only if they are either the format of a GeneralizedTime (YYYYMMDDHHMMSSZ), or a UTCTime (YYMMDDHHMMSSZ) as per RFC5280, with the exception that the requirement: "CAs conforming to this profile MUST always encode certificate validity dates through the year 2049 as UTCTime; certificate validity dates in 2050 or later MUST be encoded as GeneralizedTime." is not enforced.

X509_cmp_time() compares the ASN1_TIME in asn1_time with the time in <in_tm>.

X509_cmp_current_time() compares the ASN1_TIME in asn1_time with the current time, expressed as time_t.

X509_cmp_timeframe() compares the given time period with the reference time included in the verification parameters vpm if they are not NULL and contain X509_V_FLAG_USE_CHECK_TIME; else the current time is used as reference time.

X509_time_adj_ex() sets the ASN1_TIME structure asn1_time to the time offset_day and offset_sec after in_tm.

X509_time_adj() sets the ASN1_TIME structure asn1_time to the time offset_sec after in_tm. This method can only handle second offsets up to the capacity of long, so the newer X509_time_adj_ex() API should be preferred.

In both methods, if asn1_time is NULL, a new ASN1_TIME structure is allocated and returned.

In all methods, if in_tm is NULL, the current time, expressed as time_t, is used.

asn1_time must satisfy the ASN1_TIME format mandated by RFC 5280, i.e., its format must be either YYMMDDHHMMSSZ or YYYYMMDDHHMMSSZ.

X509_gmtime_adj() sets the ASN1_TIME structure asn1_time to the time offset_sec after the current time. It is equivalent to calling X509_time_adj() with the last parameter as NULL.

# BUGS

Unlike many standard comparison functions, The deprecated functions X509_cmp_time() and X509_cmp_current_time() return 0 on error, and return -1 when the values are equal.

The deprecated function X509_cmp_timeframe() may accept invalid certificate times as infinitely valid.

# RETURN VALUES

X509_check_certiticate_times() returns 1 if the certificate is temporally valid at the verification time as per the rules from RFC 5280. It returns 0 otherwise. if error is non NULL, the integer value it points to will be set to an error code when the certificate is not temporally valid, or 0 when the certificate is temporally valid.

The integer pointed to by error will be set to X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD or X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD if the certificate has an invalid notBefore or notAfter field, respectively.

The integer pointed to by error will be set to X509_V_ERR_CERT_NOT_YET_VALID or X509_V_ERR_CERT_HAS_EXPIRED if the verification time is outside of the certificate's correctly encoded validity window as per RFC5280.

X509_cmp_time() and X509_cmp_current_time() return -1 if asn1_time is earlier than, or equal to, in_tm (resp. current time), and 1 otherwise. These methods return 0 on error.

X509_cmp_timeframe() compares a reference time to a start and end ASN1_TIME value range. The reference time is compared to the start value of the range inclusively, and to the end value of the range exclusively. The reference time used will retrieved from vpm if the flag 509_V_FLAG_USE_CHECK_TIME is set in vpm, otherwise it will be the current time. The start time used will be start if it is non NULL, and a valid ASN1_TIME value, otherwise it will be infinitely in the past. The end time used will be end if it is non NULL and a valid ASN1_TIME value, otherwise it will be infinitely in the future. 0 is returned unconditionally if the flag X509_V_FLAG_NO_CHECK_TIME is set in vpm. Otherwise 0 will be returned if the reference time is in the range of the start time and end time as described above. 1 is returned to indicate the reference time is after or equal to the end time. -1 is returned to indicate the reference time is before the start time. As this function treats invalid ASN1_TIME inputs as unlimited times, it should not be used to for temporal verification of certificates using untrusted inputs that have not been pre-validated to be correct ASN1_TIME values for a certificate as per RFC 5280, as invalid values will be accepted as valid forever.

X509_time_adj(), X509_time_adj_ex() and X509_gmtime_adj() return a pointer to the updated ASN1_TIME structure, and NULL on error.

# SEE ALSO

ASN1_GENERALIZEDTIME_check(3) ASN1_UTCTIME_check(3) ASN1_TIME_to_tm(3) OPENSSL_tm_to_posix(3) OPENSSL_posix_to_tm(3) X509_verify_cert_error_string(3)

# HISTORY

X509_cmp_timeframe(), X509_cmp_current_time(), and X509_cmp_timeframe() were deprecated in OpenSSL 4.0

For replacement, consider using X509_check_certificate_times() for use with X509 certificates. For applications checking individual ASN1_TIME values, consider using ASN1_TIME_to_tm(3) with appropriate validity checking of the ASN1_TIME value for your application, and subsequent comparison of either the resulting tm structure, or conversion to posix seconds via OPENSSL_tm_to_posix(3)

X509_check_certificate_times() was added in OpenSSL 4.0.

# COPYRIGHT

Copyright 2017-2026 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.