警告SecTrust评估设备日志中的[leaf AnchorTrusted]

Question

我有以下代码来检索私钥

-(SecKeyRef)getKey:(NSData *)pkcs12Data
{ 
   SecKeyRef privateKeyRef = nil;

    if(pkcs12Data ==nil || pkcs12Data.length==0)
    {
       return privateKeyRef;
    }

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys: @"", kSecImportExportPassphrase, nil];
CFArrayRef items = CFArrayCreate(NULL, 0, 0, NULL);

// this line gives the warning <Error>: Nov xxxxxxx  SecTrustEvaluate  [leaf AnchorTrusted]
OSStatus returnCode = SecPKCS12Import(
                                      (__bridge CFDataRef) pkcs12Data,
                                      (__bridge CFDictionaryRef) options,
                                      & items
                                      );
if(errSecSuccess == returnCode)
{
    NSDictionary *item = (NSDictionary*) CFArrayGetValueAtIndex(items, 0);
    SecIdentityRef  identity = (__bridge SecIdentityRef) [item objectForKey:(__bridge NSString *) kSecImportItemIdentity];
    SecIdentityCopyPrivateKey(identity, &privateKeyRef);
}
else
{
    NSLog(@"failed “);
}
return privateKeyRef;
}

其中pkcs12Data是.pfx文件的数据。 虽然一切正常但我在设备日志中的SecTrustEvaluate [leaf AnchorTrusted]中收到警告。我没有任何理由这样做。请让我知道如何摆脱这个警告。