How to prepare your device to connect to Tedee Lock via Bluetooth

As an integrator, you may want to establish a secure connection between the Tedee device and your device over BLE. To do that you need to register your device and generate a certificate for it. In this tutorial, we will cover how to register a new integration device in Tedee Cloud (e.g. mobile device) and manage access certificates for it.

Note

Originally integration with Tedee devices was reserved only for mobile phones with Tedee App. Currently, we are extending the Mobile area to handle registration to our system by other external devices.

In this tutorial, we will name a device that wants to establish a secure connection over BLE with the Tedee device as mobile.

Prerequisites:

Tedee device should be added to Tedee account.

Step 1: Generate ECSDA auth pair key on the mobile

The Tedee devices are communicating only with other trusted devices. As a first step, on the mobile device, an ECDSA auth key pair should be generated. Tedee devices are using the ECDSA cryptography algorithm with uses elliptic curve cryptography. The elliptic curve base point 256 is used.

Note

We are recommending using libraries to generate the auth key pair:

C Language: MbedTLS,
iOS: CryptoSwift and native Apple framework Security for keys management,
Java: javax.crypto and java.security

Warning

The generated ECDSA private key should be kept only on the mobile device and stored securely.

Step 2: Register mobile device

Only mobiles registered in Tedee Cloud can establish secure Bluetooth connections with Tedee devices. For those mobiles, Tedee Cloud is generating access certificates.

When the auth key pair is generated on the mobile device, then it can be registered in Tedee Cloud. If you are integrating an external device operating system flag should be set to 3.

To register new mobile you should use Register mobile endpoint.

Sample request

curl -X POST "https://api.tedee.com/api/v1.33/my/mobile" -H "accept: application/json" -H "Content-Type: application/json-patch+json" -H "Authorization: Bearer <<access token>>" -d "<<body>>"

Sample body

{
    "name": "{integration device name}",
    "operatingSystem": 3,
    "publicKey": "{public as base64 key generated in step 1}"
}

Sample response

{
    "result": {
        "id": "7f8da1c1-18fb-4d79-8c19-5add0e7b92b2",
    }
    "success": true,
    "errorMessages": [],
    "statusCode": 201
}

If the registration succeed it means, your device is properly registered in Tedee Cloud. You should save the mobile identifier on the device, it will be used to retrieve and refresh access certificate.

Step 3: Get certificate for mobile device

To establish a secure BLE connection with the Tedee device, an access certificate is required. This certificate is read and validated by the Tedee device.

The access certificate is issued by Tedee Cloud with a 10-days validity period. The mobile device is responsible for requesting and refreshing the access certificates. We recommend refreshing the certificate when validity is about 40-50% remain validity period.

To generate the certificate you should use Get for mobile endpoint.

Sample request

GET https://api.tedee.com/api/v1.33/my/devicecertificate/getformobile?mobileId=7f8da1c1-18fb-4d79-8c19-5add0e7b92b2&deviceId=1

In the response the certificate data will be returned.

Sample response

{
    "result": {
        "certificate": "AQECAgECAwRhZ+ZwBAF/BQQAAAAABgQAAVF/BRhZNAACARjRgOACQQAACLdCgQAAGHMCwgAAAF7ybAKin5BBKbnztHKIog
        8hD3/OqFWBI5/oNECVRyQm5EfxZyGz/Pv7oKvlXNkF2503/RCRgocotF6rVQaYsH9c5Xq4btSF/RjBEAiDLNX00yWXmpIi0AigSb3veeFyEQRN
        sCRYbEwCZxkFe1gIgJEGKT6EoSHwPfYmPJsHCdcgtBQPiDXM/M2qJRbu6Pb4=",
        "expirationDate": "2021-12-12T00:00:00.000000Z",
        "devicePublicKey": "BL4lFWWQ0SCxYr5aLWaCUA/88XsWkVJdxihYIN0kL9VKhE9jAx8+INXVG/vsen/VEj9YltNMtb1I+qDTUdVqo8c=",
        "mobilePublicKey": "BkbnztKHIog8hD3/OqFWBI5/oNECVRyQm5EfXZyGz/Pv7oKvlXNkF2503/RCRgocotF6rVQaYsH9c5Xq4btSYKE="
    }
    "success": true,
    "errorMessages": [],
    "statusCode": 200
}

The result.certificate contains the certificate issued by Tedee Cloud, it must be passed to Tedee device when the connection is established.

Note

The access certificate is returned in bytes in Base64 format.

Step 4: Connect to Tedee Lock

Now you are ready to establish Bluetooth connection with Tedee Lock, for details read the Tedee BLE API documentation.

Step 4.1: Get time for Tedee device

To establish a secure BLE connection Tedee device require current time for proper work. When the Tedee device is not having a current time set, the mobile device is responsible for providing it.

To get current time from Tedee API you should use Get signed time endpoint.

curl -X GET "https://api.tedee.com/api/v1.33/datetime/getsignedtime" -H "accept: application/json" -H "Authorization: Bearer <<access token>>"

Sample response

{
    "result": {
        "datetime" : "AAABfHgtDbU=",
        "signature" : "MEQCIIa7NtKXDHDzynw0y5Gmi98HrA9UYnBimzXbixzaqoJiAiBDekhYsN7Eo0+d4so79zJFVni25kJJKlDklX04u7gEMA==",
    },
    "success": true,
    "errorMessages": [],
    "statusCode": 200
}