> For the complete documentation index, see [llms.txt](https://docs.payments.thalescloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.payments.thalescloud.io/secure-card-display/integrate-d1-sdk/get-started/configuration/3.-initialization/ios-initialization.md).

# iOS initialization

### Overview

`D1Task` is the main entry point to D1 SDK. It should be called as soon as the application is launched or at the earliest possible time. `D1Task.Components` is used to set a one-time configuration. The values can be retrieved from Thales delivery team.

### Configure the D1 SDK

{% stepper %}
{% step %}

### Create a `D1Task` instance

In `SceneDelegate` [scene(:willConnectTo:options:)](https://developer.apple.com/documentation/uikit/uiscenedelegate/3197914-scene), create a `D1Task` instance. Alternatively, in applications that do not use `SceneDelegate`, `D1Task` instance can be created in `AppDelegate` [application(:didFinishLaunchingWithOptions:)](https://developer.apple.com/documentation/uikit/uiapplicationdelegate/1622921-application)
{% endstep %}

{% step %}

### Configure the SDK

After setting up `D1Task`, issuer application can call the `configure` API to initialize the SDK. There are certain parameters that are required to be provided by the issuer application, for example `consumerID`.
{% endstep %}

{% step %}

### Use multi-issuer tokens

The issuer application can create multiple `D1Tasks` using multi-issuer tokens under the following conditions:

* Each issuer token may include multiple `consumerID` as the `SUB` (subject) for the same issuer.
* A single login can be performed by providing all the issuer tokens which may include multiple `consumerID` separated by spaces. Subsequently, additional operations can then be carried out across different `D1Tasks`.
  {% endstep %}
  {% endstepper %}

### Example

{% code title="SceneDelegate.swift" lineNumbers="true" %}

```swift
var d1Task: D1Task!

let PUBLIC_KEY_EXPONENT: [UInt8] = [0x00, 0xa0] // Modulus bytes array
let PUBLIC_KEY_MODULUS: [UInt8] = [0x00, 0x00] // Exponent bytes array

var comp = D1Task.Components()
comp.d1ServiceURLString = ""
comp.issuerID = ""
comp.d1ServiceRSAExponent = Data(bytes: PUBLIC_KEY_EXPONENT, count: PUBLIC_KEY_EXPONENT.count)
comp.d1ServiceRSAModulus = Data(bytes: PUBLIC_KEY_MODULUS, count: PUBLIC_KEY_MODULUS.count)
comp.digitalCardURLString = ""
d1Task = comp.task()

// Initialize required SDKs
// Issuer application is required to provide consumerID
let consumerID = "" // obtained e.g. from server
let coreConfig = ConfigParams.coreConfig(consumerID: consumerID)
// required for Card Processing & Wallet Pay
let cardConfig = ConfigParams.cardConfig()

d1Task.configure([coreConfig, cardConfig]) { (errors) in
    if let errors = errors {
        for error in errors {
            // Check error details to see whose config cause the errors, refer to D1 SDK Integration – Error Management section
        }
    }
}
```

{% endcode %}


---

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