openssl-verify, verify - Utility to verify certificates
openssl verify [-help] [-CAfile file] [-CApath
  directory] [-no-CAfile] [-no-CApath]
  [-allow_proxy_certs] [-attime timestamp] [-check_ss_sig]
  [-CRLfile file] [-crl_download] [-crl_check]
  [-crl_check_all] [-engine id] [-explicit_policy]
  [-extended_crl] [-ignore_critical] [-inhibit_any]
  [-inhibit_map] [-nameopt option] [-no_check_time]
  [-partial_chain] [-policy arg] [-policy_check]
  [-policy_print] [-purpose purpose] [-suiteB_128]
  [-suiteB_128_only] [-suiteB_192] [-trusted_first]
  [-no_alt_chains] [-untrusted file] [-trusted file]
  [-use_deltas] [-verbose] [-auth_level level]
  [-verify_depth num] [-verify_email email] [-verify_hostname
  hostname] [-verify_ip ip] [-verify_name name]
  [-x509_strict] [-show_chain] [-] [certificates]
The verify command verifies certificate chains.
  - -help
- Print out a usage message.
- -CAfile file
- A file of trusted certificates. The file should contain one or more
      certificates in PEM format.
- -CApath directory
- A directory of trusted certificates. The certificates should have names of
      the form: hash.0 or have symbolic links to them of this form
      ("hash" is the hashed certificate subject name: see the
      -hash option of the x509 utility). Under Unix the
      c_rehash script will automatically create symbolic links to a
      directory of certificates.
- -no-CAfile
- Do not load the trusted CA certificates from the default file
    location.
- -no-CApath
- Do not load the trusted CA certificates from the default directory
      location.
- -allow_proxy_certs
- Allow the verification of proxy certificates.
- -attime timestamp
- Perform validation checks using time specified by timestamp and not
      current system time. timestamp is the number of seconds since
      01.01.1970 (UNIX time).
- -check_ss_sig
- Verify the signature of the last certificate in a chain if the certificate
      is supposedly self-signed. This is prohibited and will result in an error
      if it is a non-conforming CA certificate with key usage restrictions not
      including the keyCertSign bit. This verification is disabled by default
      because it doesn't add any security.
- -CRLfile file
- The file should contain one or more CRLs in PEM format. This option
      can be specified more than once to include CRLs from multiple
      files.
- -crl_download
- Attempt to download CRL information for this certificate.
- -crl_check
- Checks end entity certificate validity by attempting to look up a valid
      CRL. If a valid CRL cannot be found an error occurs.
- -crl_check_all
- Checks the validity of all certificates in the chain by attempting
      to look up valid CRLs.
- -engine id
- Specifying an engine id will cause verify(1) to attempt to
      load the specified engine. The engine will then be set as the default for
      all its supported algorithms. If you want to load certificates or CRLs
      that require engine support via any of the -trusted,
      -untrusted or -CRLfile options, the -engine option
      must be specified before those options.
- -explicit_policy
- Set policy variable require-explicit-policy (see RFC5280).
- -extended_crl
- Enable extended CRL features such as indirect CRLs and alternate CRL
      signing keys.
- -ignore_critical
- Normally if an unhandled critical extension is present which is not
      supported by OpenSSL the certificate is rejected (as required by RFC5280).
      If this option is set critical extensions are ignored.
- -inhibit_any
- Set policy variable inhibit-any-policy (see RFC5280).
- -inhibit_map
- Set policy variable inhibit-policy-mapping (see RFC5280).
- -nameopt option
- Option which determines how the subject or issuer names are displayed. The
      option argument can be a single option or multiple options
      separated by commas. Alternatively the -nameopt switch may be used
      more than once to set multiple options. See the x509(1) manual page
      for details.
- -no_check_time
- This option suppresses checking the validity period of certificates and
      CRLs against the current time. If option -attime timestamp is used
      to specify a verification time, the check is not suppressed.
- -partial_chain
- Allow verification to succeed even if a complete chain cannot be
      built to a self-signed trust-anchor, provided it is possible to construct
      a chain to a trusted certificate that might not be self-signed.
- -policy arg
- Enable policy processing and add arg to the user-initial-policy-set
      (see RFC5280). The policy arg can be an object name an OID in
      numeric form. This argument can appear more than once.
- -policy_check
- Enables certificate policy processing.
- -policy_print
- Print out diagnostics related to policy processing.
- -purpose purpose
- The intended use for the certificate. If this option is not specified,
      verify will not consider certificate purpose during chain
      verification. Currently accepted uses are sslclient,
      sslserver, nssslserver, smimesign,
      smimeencrypt. See the VERIFY OPERATION section for more
      information.
- -suiteB_128_only, -suiteB_128, -suiteB_192
- Enable the Suite B mode operation at 128 bit Level of Security, 128 bit or
      192 bit, or only 192 bit Level of Security respectively. See RFC6460 for
      details. In particular the supported signature algorithms are reduced to
      support only ECDSA and SHA256 or SHA384 and only the elliptic curves P-256
      and P-384.
- -trusted_first
- When constructing the certificate chain, use the trusted certificates
      specified via -CAfile, -CApath or -trusted before any
      certificates specified via -untrusted. This can be useful in
      environments with Bridge or Cross-Certified CAs. As of OpenSSL 1.1.0 this
      option is on by default and cannot be disabled.
- -no_alt_chains
- By default, unless -trusted_first is specified, when building a
      certificate chain, if the first certificate chain found is not trusted,
      then OpenSSL will attempt to replace untrusted issuer certificates with
      certificates from the trust store to see if an alternative chain can be
      found that is trusted. As of OpenSSL 1.1.0, with -trusted_first
      always on, this option has no effect.
- -untrusted file
- A file of additional untrusted certificates (intermediate issuer
      CAs) used to construct a certificate chain from the subject certificate to
      a trust-anchor. The file should contain one or more certificates in
      PEM format. This option can be specified more than once to include
      untrusted certificates from multiple files.
- -trusted file
- A file of trusted certificates, which must be self-signed, unless
      the -partial_chain option is specified. The file contains
      one or more certificates in PEM format. With this option, no additional
      (e.g., default) certificate lists are consulted. That is, the only
      trust-anchors are those listed in file. This option can be
      specified more than once to include trusted certificates from multiple
      files. This option implies the -no-CAfile and
      -no-CApath options. This option cannot be used in combination with
      either of the -CAfile or -CApath options.
- -use_deltas
- Enable support for delta CRLs.
- -verbose
- Print extra information about the operations being performed.
- -auth_level level
- Set the certificate chain authentication security level to level.
      The authentication security level determines the acceptable signature and
      public key strength when verifying certificate chains. For a certificate
      chain to validate, the public keys of all the certificates must meet the
      specified security level. The signature algorithm security level is
      enforced for all the certificates in the chain except for the chain's
      trust anchor, which is either directly trusted or validated by
      means other than its signature. See SSL_CTX_set_security_level(3)
      for the definitions of the available levels. The default security level is
      -1, or "not set". At security level 0 or lower all algorithms
      are acceptable. Security level 1 requires at least 80-bit-equivalent
      security and is broadly interoperable, though it will, for example, reject
      MD5 signatures or RSA keys shorter than 1024 bits.
- -verify_depth num
- Limit the certificate chain to num intermediate CA certificates. A
      maximal depth chain can have up to num+2 certificates, since
      neither the end-entity certificate nor the trust-anchor certificate count
      against the -verify_depth limit.
- -verify_email email
- Verify if the email matches the email address in Subject
      Alternative Name or the email in the subject Distinguished Name.
- -verify_hostname hostname
- Verify if the hostname matches DNS name in Subject Alternative Name
      or Common Name in the subject certificate.
- -verify_ip ip
- Verify if the ip matches the IP address in Subject Alternative Name
      of the subject certificate.
- -verify_name name
- Use default verification policies like trust model and required
      certificate policies identified by name. The trust model determines
      which auxiliary trust or reject OIDs are applicable to verifying the given
      certificate chain. See the -addtrust and -addreject options
      of the x509(1) command-line utility. Supported policy names
      include: default, pkcs7, smime_sign,
      ssl_client, ssl_server. These mimics the combinations of
      purpose and trust settings used in SSL, CMS and S/MIME. As of OpenSSL
      1.1.0, the trust model is inferred from the purpose when not specified, so
      the -verify_name options are functionally equivalent to the
      corresponding -purpose settings.
- -x509_strict
- For strict X.509 compliance, disable non-compliant workarounds for broken
      certificates.
- -show_chain
- Display information about the certificate chain that has been built (if
      successful). Certificates in the chain that came from the untrusted list
      will be flagged as "untrusted".
- -
- Indicates the last option. All arguments following this are assumed to be
      certificate files. This is useful if the first certificate filename begins
      with a -.
- certificates
- One or more certificates to verify. If no certificates are given,
      verify will attempt to read a certificate from standard input.
      Certificates must be in PEM format.
The verify program uses the same functions as the internal SSL and S/MIME
  verification, therefore, this description applies to these verify operations
  too.There is one crucial difference between the verify operations
    performed by the verify program: wherever possible an attempt is made
    to continue after an error whereas normally the verify operation would halt
    on the first error. This allows all the problems with a certificate chain to
    be determined.
The verify operation consists of a number of separate steps.
Firstly a certificate chain is built up starting from the supplied
    certificate and ending in the root CA. It is an error if the whole chain
    cannot be built up. The chain is built up by looking up the issuers
    certificate of the current certificate. If a certificate is found which is
    its own issuer it is assumed to be the root CA.
The process of 'looking up the issuers certificate' itself
    involves a number of steps. After all certificates whose subject name
    matches the issuer name of the current certificate are subject to further
    tests. The relevant authority key identifier components of the current
    certificate (if present) must match the subject key identifier (if present)
    and issuer and serial number of the candidate issuer, in addition the
    keyUsage extension of the candidate issuer (if present) must permit
    certificate signing.
The lookup first looks in the list of untrusted certificates and
    if no match is found the remaining lookups are from the trusted
    certificates. The root CA is always looked up in the trusted certificate
    list: if the certificate to verify is a root certificate then an exact match
    must be found in the trusted list.
The second operation is to check every untrusted certificate's
    extensions for consistency with the supplied purpose. If the -purpose
    option is not included then no checks are done. The supplied or
    "leaf" certificate must have extensions compatible with the
    supplied purpose and all other certificates must also be valid CA
    certificates. The precise extensions required are described in more detail
    in the CERTIFICATE EXTENSIONS section of the x509 utility.
The third operation is to check the trust settings on the root CA.
    The root CA should be trusted for the supplied purpose. For compatibility
    with previous versions of OpenSSL, a certificate with no trust settings is
    considered to be valid for all purposes.
The final operation is to check the validity of the certificate
    chain. For each element in the chain, including the root CA certificate, the
    validity period as specified by the
    "notBefore" and
    "notAfter" fields is checked against the
    current system time. The -attime flag may be used to use a reference
    time other than "now." The certificate signature is checked as
    well (except for the signature of the typically self-signed root CA
    certificate, which is verified only if the -check_ss_sig option is
    given).
If all operations complete successfully then certificate is
    considered valid. If any operation fails then the certificate is not
  valid.
When a verify operation fails the output messages can be somewhat cryptic. The
  general form of the error message is:
 server.pem: /C=AU/ST=Queensland/O=CryptSoft Pty Ltd/CN=Test CA (1024 bit)
 error 24 at 1 depth lookup:invalid CA certificate
The first line contains the name of the certificate being verified
    followed by the subject name of the certificate. The second line contains
    the error number and the depth. The depth is number of the certificate being
    verified when a problem was detected starting with zero for the certificate
    being verified itself then 1 for the CA that signed the certificate and so
    on. Finally a text version of the error number is presented.
A partial list of the error codes and messages is shown below,
    this also includes the name of the error code as defined in the header file
    x509_vfy.h Some of the error codes are defined but never returned: these are
    described as "unused".
  - X509_V_OK
- The operation was successful.
- X509_V_ERR_UNSPECIFIED
- Unspecified error; should not happen.
- X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT
- The issuer certificate of a looked up certificate could not be found. This
      normally means the list of trusted certificates is not complete.
- X509_V_ERR_UNABLE_TO_GET_CRL
- The CRL of a certificate could not be found.
- X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE
- The certificate signature could not be decrypted. This means that the
      actual signature value could not be determined rather than it not matching
      the expected value, this is only meaningful for RSA keys.
- X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE
- The CRL signature could not be decrypted: this means that the actual
      signature value could not be determined rather than it not matching the
      expected value. Unused.
- X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY
- The public key in the certificate SubjectPublicKeyInfo could not be
    read.
- X509_V_ERR_CERT_SIGNATURE_FAILURE
- The signature of the certificate is invalid.
- X509_V_ERR_CRL_SIGNATURE_FAILURE
- The signature of the certificate is invalid.
- X509_V_ERR_CERT_NOT_YET_VALID
- The certificate is not yet valid: the notBefore date is after the current
      time.
- X509_V_ERR_CERT_HAS_EXPIRED
- The certificate has expired: that is the notAfter date is before the
      current time.
- X509_V_ERR_CRL_NOT_YET_VALID
- The CRL is not yet valid.
- X509_V_ERR_CRL_HAS_EXPIRED
- The CRL has expired.
- X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD
- The certificate notBefore field contains an invalid time.
- X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD
- The certificate notAfter field contains an invalid time.
- X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD
- The CRL lastUpdate field contains an invalid time.
- X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD
- The CRL nextUpdate field contains an invalid time.
- X509_V_ERR_OUT_OF_MEM
- An error occurred trying to allocate memory. This should never
    happen.
- X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT
- The passed certificate is self-signed and the same certificate cannot be
      found in the list of trusted certificates.
- X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN
- The certificate chain could be built up using the untrusted certificates
      but the root could not be found locally.
- X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY
- The issuer certificate could not be found: this occurs if the issuer
      certificate of an untrusted certificate cannot be found.
- X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE
- No signatures could be verified because the chain contains only one
      certificate and it is not self signed.
- X509_V_ERR_CERT_CHAIN_TOO_LONG
- The certificate chain length is greater than the supplied maximum depth.
      Unused.
- X509_V_ERR_CERT_REVOKED
- The certificate has been revoked.
- X509_V_ERR_INVALID_CA
- A CA certificate is invalid. Either it is not a CA or its extensions are
      not consistent with the supplied purpose.
- X509_V_ERR_PATH_LENGTH_EXCEEDED
- The basicConstraints pathlength parameter has been exceeded.
- X509_V_ERR_INVALID_PURPOSE
- The supplied certificate cannot be used for the specified purpose.
- X509_V_ERR_CERT_UNTRUSTED
- The root CA is not marked as trusted for the specified purpose.
- X509_V_ERR_CERT_REJECTED
- The root CA is marked to reject the specified purpose.
- X509_V_ERR_SUBJECT_ISSUER_MISMATCH
- Not used as of OpenSSL 1.1.0 as a result of the deprecation of the
      -issuer_checks option.
- X509_V_ERR_AKID_SKID_MISMATCH
- Not used as of OpenSSL 1.1.0 as a result of the deprecation of the
      -issuer_checks option.
- X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH
- Not used as of OpenSSL 1.1.0 as a result of the deprecation of the
      -issuer_checks option.
- X509_V_ERR_KEYUSAGE_NO_CERTSIGN
- Not used as of OpenSSL 1.1.0 as a result of the deprecation of the
      -issuer_checks option.
- X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER
- Unable to get CRL issuer certificate.
- X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION
- Unhandled critical extension.
- X509_V_ERR_KEYUSAGE_NO_CRL_SIGN
- Key usage does not include CRL signing.
- X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION
- Unhandled critical CRL extension.
- X509_V_ERR_INVALID_NON_CA
- Invalid non-CA certificate has CA markings.
- X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED
- Proxy path length constraint exceeded.
- X509_V_ERR_PROXY_SUBJECT_INVALID
- Proxy certificate subject is invalid. It MUST be the same as the issuer
      with a single CN component added.
- X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE
- Key usage does not include digital signature.
- X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED
- Proxy certificates not allowed, please use -allow_proxy_certs.
- X509_V_ERR_INVALID_EXTENSION
- Invalid or inconsistent certificate extension.
- X509_V_ERR_INVALID_POLICY_EXTENSION
- Invalid or inconsistent certificate policy extension.
- X509_V_ERR_NO_EXPLICIT_POLICY
- No explicit policy.
- X509_V_ERR_DIFFERENT_CRL_SCOPE
- Different CRL scope.
- X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE
- Unsupported extension feature.
- X509_V_ERR_UNNESTED_RESOURCE
- RFC 3779 resource not subset of parent's resources.
- X509_V_ERR_PERMITTED_VIOLATION
- Permitted subtree violation.
- X509_V_ERR_EXCLUDED_VIOLATION
- Excluded subtree violation.
- X509_V_ERR_SUBTREE_MINMAX
- Name constraints minimum and maximum not supported.
- X509_V_ERR_APPLICATION_VERIFICATION
- Application verification failure. Unused.
- X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE
- Unsupported name constraint type.
- X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX
- Unsupported or invalid name constraint syntax.
- X509_V_ERR_UNSUPPORTED_NAME_SYNTAX
- Unsupported or invalid name syntax.
- X509_V_ERR_CRL_PATH_VALIDATION_ERROR
- CRL path validation error.
- X509_V_ERR_PATH_LOOP
- Path loop.
- X509_V_ERR_SUITE_B_INVALID_VERSION
- Suite B: certificate version invalid.
- X509_V_ERR_SUITE_B_INVALID_ALGORITHM
- Suite B: invalid public key algorithm.
- X509_V_ERR_SUITE_B_INVALID_CURVE
- Suite B: invalid ECC curve.
- X509_V_ERR_SUITE_B_INVALID_SIGNATURE_ALGORITHM
- Suite B: invalid signature algorithm.
- X509_V_ERR_SUITE_B_LOS_NOT_ALLOWED
- Suite B: curve not allowed for this LOS.
- X509_V_ERR_SUITE_B_CANNOT_SIGN_P_384_WITH_P_256
- Suite B: cannot sign P-384 with P-256.
- X509_V_ERR_HOSTNAME_MISMATCH
- Hostname mismatch.
- X509_V_ERR_EMAIL_MISMATCH
- Email address mismatch.
- X509_V_ERR_IP_ADDRESS_MISMATCH
- IP address mismatch.
- X509_V_ERR_DANE_NO_MATCH
- DANE TLSA authentication is enabled, but no TLSA records matched the
      certificate chain. This error is only possible in s_client(1).
- X509_V_ERR_EE_KEY_TOO_SMALL
- EE certificate key too weak.
- X509_ERR_CA_KEY_TOO_SMALL
- CA certificate key too weak.
- X509_ERR_CA_MD_TOO_WEAK
- CA signature digest algorithm too weak.
- X509_V_ERR_INVALID_CALL
- nvalid certificate verification context.
- X509_V_ERR_STORE_LOOKUP
- Issuer certificate lookup error.
- X509_V_ERR_NO_VALID_SCTS
- Certificate Transparency required, but no valid SCTs found.
- X509_V_ERR_PROXY_SUBJECT_NAME_VIOLATION
- Proxy subject name violation.
- X509_V_ERR_OCSP_VERIFY_NEEDED
- Returned by the verify callback to indicate an OCSP verification is
      needed.
- X509_V_ERR_OCSP_VERIFY_FAILED
- Returned by the verify callback to indicate OCSP verification failed.
- X509_V_ERR_OCSP_CERT_UNKNOWN
- Returned by the verify callback to indicate that the certificate is not
      recognized by the OCSP responder.
Although the issuer checks are a considerable improvement over the old technique
  they still suffer from limitations in the underlying X509_LOOKUP API. One
  consequence of this is that trusted certificates with matching subject name
  must either appear in a file (as specified by the -CAfile option) or a
  directory (as specified by -CApath). If they occur in both then only
  the certificates in the file will be recognised.Previous versions of OpenSSL assume certificates with matching
    subject name are identical and mishandled them.
Previous versions of this documentation swapped the meaning of the
    X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT and
    X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY error codes.
The -show_chain option was added in OpenSSL 1.1.0.
The -issuer_checks option is deprecated as of OpenSSL 1.1.0
    and is silently ignored.
Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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>.