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CT_POLICY_EVAL_CTX_new(3)           OpenSSL          CT_POLICY_EVAL_CTX_new(3)



NAME
       CT_POLICY_EVAL_CTX_new_ex, CT_POLICY_EVAL_CTX_new,
       CT_POLICY_EVAL_CTX_free, CT_POLICY_EVAL_CTX_get0_cert,
       CT_POLICY_EVAL_CTX_set1_cert, CT_POLICY_EVAL_CTX_get0_issuer,
       CT_POLICY_EVAL_CTX_set1_issuer, CT_POLICY_EVAL_CTX_get0_log_store,
       CT_POLICY_EVAL_CTX_set_shared_CTLOG_STORE, CT_POLICY_EVAL_CTX_get_time,
       CT_POLICY_EVAL_CTX_set_time - Encapsulates the data required to
       evaluate whether SCTs meet a Certificate Transparency policy

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/ct.h>

        CT_POLICY_EVAL_CTX *CT_POLICY_EVAL_CTX_new_ex(OSSL_LIB_CTX *libctx,
                                                      const char *propq);
        CT_POLICY_EVAL_CTX *CT_POLICY_EVAL_CTX_new(void);
        void CT_POLICY_EVAL_CTX_free(CT_POLICY_EVAL_CTX *ctx);
        X509* CT_POLICY_EVAL_CTX_get0_cert(const CT_POLICY_EVAL_CTX *ctx);
        int CT_POLICY_EVAL_CTX_set1_cert(CT_POLICY_EVAL_CTX *ctx, X509 *cert);
        X509* CT_POLICY_EVAL_CTX_get0_issuer(const CT_POLICY_EVAL_CTX *ctx);
        int CT_POLICY_EVAL_CTX_set1_issuer(CT_POLICY_EVAL_CTX *ctx, X509 *issuer);
        const CTLOG_STORE *CT_POLICY_EVAL_CTX_get0_log_store(const CT_POLICY_EVAL_CTX *ctx);
        void CT_POLICY_EVAL_CTX_set_shared_CTLOG_STORE(CT_POLICY_EVAL_CTX *ctx,
                                                       CTLOG_STORE *log_store);
        uint64_t CT_POLICY_EVAL_CTX_get_time(const CT_POLICY_EVAL_CTX *ctx);
        void CT_POLICY_EVAL_CTX_set_time(CT_POLICY_EVAL_CTX *ctx, uint64_t time_in_ms);

DESCRIPTION
       A CT_POLICY_EVAL_CTX is used by functions that evaluate whether Signed
       Certificate Timestamps (SCTs) fulfil a Certificate Transparency (CT)
       policy.  This policy may be, for example, that at least one valid SCT
       is available. To determine this, an SCT's timestamp and signature must
       be verified.  This requires:

       ⊕ the public key of the log that issued the SCT

       ⊕ the certificate that the SCT was issued for

       ⊕ the issuer certificate (if the SCT was issued for a pre-certificate)

       ⊕ the current time

       The above requirements are met using the setters described below.

       CT_POLICY_EVAL_CTX_new_ex() creates an empty policy evaluation context
       and associates it with the given library context libctx and property
       query string propq.

       CT_POLICY_EVAL_CTX_new() does the same thing as
       CT_POLICY_EVAL_CTX_new_ex() except that it uses the default library
       context and property query string.

       The CT_POLICY_EVAL_CTX should then be populated using:

       ⊕ CT_POLICY_EVAL_CTX_set1_cert() to provide the certificate the SCTs
         were issued for

         Increments the reference count of the certificate.

       ⊕ CT_POLICY_EVAL_CTX_set1_issuer() to provide the issuer certificate

         Increments the reference count of the certificate.

       ⊕ CT_POLICY_EVAL_CTX_set_shared_CTLOG_STORE() to provide a list of logs
         that are trusted as sources of SCTs

         Holds a pointer to the CTLOG_STORE, so the CTLOG_STORE must outlive
         the CT_POLICY_EVAL_CTX.

       ⊕ CT_POLICY_EVAL_CTX_set_time() to set the time SCTs should be compared
         with to determine if they are valid

         The SCT timestamp will be compared to this time to check whether the
         SCT was issued in the future. RFC6962 states that "TLS clients MUST
         reject SCTs whose timestamp is in the future". By default, this will
         be set to 5 minutes in the future (e.g. (time() + 300) * 1000), to
         allow for clock drift.

         The time should be in milliseconds since the Unix Epoch.

       Each setter has a matching getter for accessing the current value.

       When no longer required, the CT_POLICY_EVAL_CTX should be passed to
       CT_POLICY_EVAL_CTX_free() to delete it.

NOTES
       The issuer certificate only needs to be provided if at least one of the
       SCTs was issued for a pre-certificate. This will be the case for SCTs
       embedded in a certificate (i.e. those in an X.509 extension), but may
       not be the case for SCTs found in the TLS SCT extension or OCSP
       response.

RETURN VALUES
       CT_POLICY_EVAL_CTX_new_ex() and CT_POLICY_EVAL_CTX_new() will return
       NULL if malloc fails.

SEE ALSO
       ct(7)

HISTORY
       CT_POLICY_EVAL_CTX_new_ex was added in OpenSSL 3.0. All other functions
       were added in OpenSSL 1.1.0.

COPYRIGHT
       Copyright 2016-2020 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>.



3.0.12                            2023-05-07         CT_POLICY_EVAL_CTX_new(3)