a495a34c___and_Trust_Services_Reference__Value
[Key] kSecTrustSettingsAllowedError [Value] 
A CFNumber containing an SInt32 value indicating a CSSM_RETURN result code which, if encountered during certificate verification, is ignored for that certificate. These “allowed error” values are applied to the evaluation only if the usage constraints dictionary meets the criteria described with the kSecTrustSettingsResult key. A usage constraint dictionary with no constraints but with an allowed error value causes that error to always be allowed when the certificate is being evaluated.
Certificate, Key, and Trust Services Reference