a495a34c___and_Trust_Services_Reference__Value
[Key] kSecTrustSettingsResult [Value] 
A CFNumber containing an SInt32 value indicating the effective trust setting for this usage constraints dictionary. A given usage constraints dictionary is included in the evaluation of trust for a certificate only if the specified policy, application, and key use match the use for which the certificate is being evaluated. If this is the case, then the value of the kSecTrustSettingsResult key is ORed with the results from other dictionaries to determine the overall trust setting for the certificate. If this key is not present, a default value of kSecTrustSettingsResultTrustRoot is assumed. Because only a root certificate can have this value, a usage constraints dictionary for a non-root certificate that is missing this key is not valid. Possible values for this key are listed in Trust Settings Result Constants.
Certificate, Key, and Trust Services Reference