// USE KEYCHAIN IDENTITY IF EXISTS
// Check if Id exists in keychain. If so use that Id
do {
    if let thisIdentity = try TLSIdentity.identity(withLabel: "doco-sync-server") {
        print("An identity with label : doco-sync-server already exists in keychain")
        return thisIdentity
        }
} catch
  {return nil}

// CREATE IDENTITY FROM BUNDLED RESOURCE IF FOUND

        // Check for a resource bundle with required label to generate identity from
        // return nil identify if not found
        guard let pathToCert = Bundle.main.path(forResource: "doco-sync-server", ofType: "p12"),
                let thisData = NSData(contentsOfFile: pathToCert)
            else
                {return nil}

// Use SecPKCS12Import to import the contents (identities and certificates)
// of the required resource bundle (PKCS #12 formatted blob).
//
// Set passphrase using kSecImportExportPassphrase.
// This passphrase should correspond to what was specified when .p12 file was created
kcStatus = SecPKCS12Import(thisData as CFData, [String(kSecImportExportPassphrase): "couchbase"] as CFDictionary, &items)
    if kcStatus != errSecSuccess {
     print("failed to import data from provided with error :\(kcStatus) ")
     return nil
    }
let importedItems = items! as NSArray
let thisItem = importedItems[0] as! [String: Any]

// Get SecIdentityRef representing the item's id
let thisSecId = thisItem[String(kSecImportItemIdentity)]  as! SecIdentity

// Get Id's Private Key, return nil id if fails
var thisPrivateKey : SecKey?
kcStatus = SecIdentityCopyPrivateKey(thisSecId, &thisPrivateKey)
    if kcStatus != errSecSuccess {
        print("failed to import private key from provided with error :\(kcStatus) ")
        return nil
    }

// Get all relevant certs [SecCertificate] from the ID's cert chain using kSecImportItemCertChain
let thisCertChain = thisItem[String(kSecImportItemCertChain)] as? [SecCertificate]

// Return nil Id if errors in key or cert chain at this stage
guard let pKey = thisPrivateKey, let pubCerts = thisCertChain else {
    return nil
}

// STORE THE IDENTITY AND ITS CERT CHAIN IN THE KEYCHAIN

        // Store Private Key in Keychain
        let params: [String : Any] = [
            String(kSecClass):          kSecClassKey,
            String(kSecAttrKeyType):    kSecAttrKeyTypeRSA,
            String(kSecAttrKeyClass):   kSecAttrKeyClassPrivate,
            String(kSecValueRef):       pKey
        ]
        kcStatus = SecItemAdd(params as CFDictionary, nil)
            if kcStatus != errSecSuccess {
                print("Unable to store private key")
                return nil
            }
       // Store all Certs for Id in Keychain:
       var i = 0;
       for cert in thisCertChain! {
            let params: [String : Any] = [
                String(kSecClass):      kSecClassCertificate,
                String(kSecValueRef):   cert,
                String(kSecAttrLabel):  "doco-sync-server"
                ]
            kcStatus = SecItemAdd(params as CFDictionary, nil)
                if kcStatus != errSecSuccess {
                    print("Unable to store certs")
                    return nil
                }
            i=i+1
        }

// RETURN A TLSIDENTITY FROM THE KEYCHAIN FOR USE IN CONFIGURING TLS COMMUNICATION
do {
    return try TLSIdentity.identity(withIdentity: thisSecId, certs: [pubCerts[0]])
} catch {
    print("Error while loading self signed cert : \(error)")
    return nil
}