Select platform: [Android](https://developers.google.com/interactive-media-ads/docs/sdks/android/client-side/secure-signals-developer.md.txt "View this page for the Android platform docs.") [iOS](https://developers.google.com/interactive-media-ads/docs/sdks/ios/client-side/secure-signals-developer.md.txt "View this page for the iOS platform docs.")

<br />

Secure signals are encoded data a client device collects and shares with select
bidders. This page guides you on collecting and sending secure signals to
Google Ad Manager using the Interactive Media Ads (IMA) SDK.

## Before you begin

Before continuing, verify you have the IMA SDK for
iOS v3.18.5 or higher.

## Create the secure signal adapter interface

To collect and provide secure signals, create classes that implement the
interface:

### Objective-C

- **MySecureSignalsAdapter.h**:

```objective-c
#import <Foundation/Foundation.h>
#import <GoogleInteractiveMediaAds/GoogleInteractiveMediaAds.h>
/** An example implementation of Secure Signals adapter. */
@interface MySecureSignalsAdapter : NSObject <IMASecureSignalsAdapter>
@end
```

- **MySecureSignalsAdapter.m**:

```objective-c
@implementation MySecureSignalsAdapter

  /**
* Default constructor with no arguments for IMA SDK to instantiate this class.
*/
- (instancetype)init {
  self = [super init];

  return self;
}
@end
```

### Swift

```swift
import Foundation
import GoogleInteractiveMediaAds

/** An example implementation of Secure Signals adapter. */
@objc(MySecureSignalsAdapter)
public class MySecureSignalsAdapter: IMASecureSignalsAdapter {
  /**
  * Default constructor with no arguments for IMA SDK to instantiate this class.
  */
  override init() {
    super.init()
  }
}
```

## Initialize the adapter

The IMA SDK initializes each adapter once by calling the initialization method
of the adapter. Implement this method to begin any encryption dependencies, set
up caches, or pre-calculating any signals that remain the same in all signal
collection calls.

The following example initializes the adapter:

### Objective-C

```objective-c
...
@interface MySecureSignalsAdapter
@property(nonatomic) NSError *initError;
@end
...
/**
* Initialize your SDK and any dependencies.
* IMA SDK calls this function exactly once before signal collection.
*/
- (instancetype)init {
  self = [super init];
  @try {
    // Initialize your SDK and any dependencies.
    ...
  }
  @catch(NSException *exception) {
    // Build NSError to be passed by Signal Collector.
    _initError = ...;
  }
  return self;
}
...
```

### Swift

```swift
...
@objc(MySecureSignalsAdapter)
public class MySecureSignalsAdapter: IMASecureSignalsAdapter {
...
  private var initError

  override init() {
    super.init()

    do {
      // Initialize your SDK and any dependencies.
      ...
    } catch {
      // Build NSError to be passed by Signal Collector.
      self.initError = ...;
    }
  }
}
```

## Signal collection

Before an ad request initiates, the IMA SDK calls a collect signals method
asynchronously. These signal collector methods contain a callback function to
pass the encrypted signals or report an error.

> [!NOTE]
> **Note:** Within 500 milliseconds, you must complete the signal collection, encryption, and pass the encrypted signal to the callback function. After 500 milliseconds, the IMA SDK discards any signal collection.

The following examples collect the secure signals through the callback
function:

### Objective-C

```objective-c
...
/**
* Invokes your SDK to collect, encrypt and pass the signal collection results to IMA SDK.
* IMA SDK calls this function before each ad request.
*
* @param completion A callback function to pass signal collection results to IMA SDK.
*/
- (void)collectSignalsWithCompletion:(IMASignalCompletionHandler)completion {
  // Output any initialization errors
  if (self.initError) {
    completion(nil, self.initError);
    return;
  }
  @try {
    // Collect and encrypt the signals.
    NSString *signals = ...
    // Pass the encrypted signals to IMA SDK.
    completion(signals, nil);
  }
  @catch(NSException *exception) {
    NSError *collectSignalError = ...;
    // Pass signal collection failures to IMA SDK.
    completion(nil, collectSignalError);
  }
}
...
```

### Swift

```swift
...
  /**
  * Invokes your SDK to collect, encrypt and pass the signal collection results to IMA SDK.
  * IMA SDK calls this function before each ad request.
  *
  * @param completion A callback function to pass signal collection results to IMA SDK.
  */
  public func collectSignals(completion: @escaping IMASignalCompletionHandler) {
    if (self.initError) {
      completion(nil, self.initError)
      return
    }

    do {
      // Collect and encrypt the signals.
      var signals = ...
      // Pass the encrypted signals to IMA SDK.
      completion(signals, nil)
    } catch {
      NSError collectSignalError = ...
      // Pass signal collection failures to IMA SDK.
      completion(nil, collectSignalError)
    }
  }
...
```

## Report errors

To communicate with users who use your adapter class, report all errors during
the signal collection and pass them to the signal collector callback. This
process troubleshoots issues that occur during integration of your adapter to
applications.

Errors that might appear are as follows:

- Your SDK or a dependency is not found in the application.
- Your SDK or a dependency doesn't have the required permission or user consent to work.

### Specify the adapter version

In your workflow, verify you specify the version of the adapter. The IMA SDK
includes your adapter version in each ad request and passes them with the secure
signals in a bid request.

In the bid request, based on the adapter version, you can identify the
encryption, encoding, and formatting details the adapter uses to create the
secure signals.

The following example specifies the adapter version:

### Objective-C

```objective-c
...
/**
* Specifies this adapter's version.
*/
static NSInteger const VersionMajor = 1;
static NSInteger const VersionMinor = 0;
static NSInteger const VersionPatch = 1;
...
/**
* @return The version of this adapter.
*         IMA SDK calls this function before each ad request.
*/
+ (IMAVersion *)adapterVersion {
  // The version of the SecureSignals Adapter.
  IMAVersion *adapterVersion = [[IMAVersion alloc] init];
  adapterVersion.majorVersion = VersionMajor;
  adapterVersion.minorVersion = VersionMinor;
  adapterVersion.patchVersion = VersionPatch;
  return adapterVersion;
}
...
```

### Swift

```swift
...
  /**
  * Specifies this adapter's version.
  */
  static let VersionMajor = 1;
  static let VersionMinor = 0;
  static let VersionPatch = 1;
...
  /**
  * @return The version of this adapter.
  *         IMA SDK calls this function before each ad request.
  */
  public static func adapterVersion() -> IMAVersion {
    let adapterVersion = IMAVersion()
    adapterVersion.majorVersion = self.VersionMajor
    adapterVersion.minorVersion = self.VersionMinor
    adapterVersion.patchVersion = self.VersionPatch
    return adapterVersion
  }
...
```

## Return the SDK runtime version

You can design your adapter to work with multiple versions of your SDK. For the
adapter to work with multiple versions, verify you return the runtime version of
the SDK. In each ad request, the IMA SDK includes the runtime version with the
adapter version.

The following examples requests and returns the SDK runtime version:

### Objective-C

```objective-c
...
/**
* @return The version of your SDK that this adapter is depending on.
*         IMA SDK calls this function before each ad request.
*/
+ (IMAVersion *)adSDKVersion {
  // Request the version from your SDK and convert to an IMAVersion.
  int mySDKVersion[3] = ...

  IMAVersion *adSDKVersion = [[IMAVersion alloc] init];
  adSDKVersion.majorVersion = mySDKVersion[0];
  adSDKVersion.minorVersion = mySDKVersion[1];
  adSDKVersion.patchVersion = mySDKVersion[2];

  return adSDKVersion;
}
...
```

### Swift

```swift
...
  /**
  * @return The version of your SDK that this adapter is depending on.
  *         IMA SDK calls this function before each ad request.
  */
public static func adSDKVersion() -> IMAVersion {
    // Request the version from your SDK and convert to an IMAVersion.
    let mySDKVersion = ...

    let adSDKVersion = IMAVersion()
    adSDKVersion.majorVersion = mySDKVersion[0]
    adSDKVersion.minorVersion = mySDKVersion[1]
    adSDKVersion.patchVersion = mySDKVersion[2]
    return adSDKVersion
  }
...
```

## Register the adapter with Google

For Google to authorize the adapter for signal collection, you must register
the iOS class name with Google.
The IMA SDK initializes only those adapters you register with Google.

## Validate the adapter

To validate the adapter, complete the following sections:

### Configure the test application

Before you validate the adapter, configure the test application. Complete the
following steps:

1. [Add IMA SDK to your XCode project](https://developers.google.com/interactive-media-ads/docs/sdks/ios/client-side#2_add_the_ima_sdk_to_the_xcode_project).

2. Add your secure signals adapter to your XCode project.

### Verify the signals

To verify the length of the secure signal, the encrypted value, your adapter
version; and your SDK version, contact support to share the captured traffic
log.

## Review the complete examples

This section captures the completed example of all steps and available for your
reference.

### Objective-C

- **MySecureSignalsAdapter.h**:

```objective-c
#import <Foundation/Foundation.h>
#import <GoogleInteractiveMediaAds/GoogleInteractiveMediaAds.h>

/** An example implementation of Secure Signals adapter. */
@interface MySecureSignalsAdapter : NSObject <IMASecureSignalsAdapter>
@end
```

- **MySecureSignalsAdapter.m**:

```objective-c
#import "path/to/MyExampleSecureSignalsAdapter.h"

@interface MySecureSignalsAdapter
@property(nonatomic) NSError *initError;
@end

static NSInteger const VersionMajor = 1;
static NSInteger const VersionMinor = 0;
static NSInteger const VersionPatch = 1;

@implementation MySecureSignalsAdapter
/**
* Initialize your SDK and any dependencies.
* IMA SDK calls this function exactly once before signal collection.
*/
- (instancetype)init {
  self = [super init];
  @try {
    // Initialize your SDK and any dependencies.
    ...
  }
  @catch(NSException *exception) {
    // Build NSError to be passed by Signal Collector.
    _initError = ...;
  }
  return self;
}
/**
* Invokes your SDK to collect, encrypt and pass the signal collection results to IMA SDK.
* IMA SDK calls this function before each ad request.
*
* @param completion A callback function to pass signal collection results to IMA SDK.
*/
- (void)collectSignalsWithCompletion:(IMASignalCompletionHandler)completion {
  if (self.initError) {
    completion(nil, self.initError);
    return;
  }
  @try {
    // Collect and encrypt the signals.
    NSString *signals = ...
    // Pass the encrypted signals to IMA SDK.
    completion(signals, nil);
  }
  @catch(NSException *exception) {
    NSError *collectSignalError = ...;
    // Pass signal collection failures to IMA SDK.
    completion(nil, collectSignalError);
  }
}
/**
* @return The version of this adapter.
*         IMA SDK calls this function before each ad request.
*/
+ (IMAVersion *)adapterVersion {
  // The version of the SecureSignals Adapter.
  IMAVersion *adapterVersion = [[IMAVersion alloc] init];
  adapterVersion.majorVersion = VersionMajor;
  adapterVersion.minorVersion = VersionMinor;
  adapterVersion.patchVersion = VersionPatch;
  return adapterVersion;
}

/**
  * @return The version of your SDK that this adapter depends on.
  *         IMA SDK calls this function before each ad request.
  */
+ (IMAVersion *)adSDKVersion {
  // Request the version from your SDK and convert to an IMAVersion.
  int mySDKVersion[3] = ...

  IMAVersion *adSDKVersion = [[IMAVersion alloc] init];
  adSDKVersion.majorVersion = mySDKVersion[0];
  adSDKVersion.minorVersion = mySDKVersion[1];
  adSDKVersion.patchVersion = mySDKVersion[2];

  return adSDKVersion;
}

@end
```

### Swift

```swift
@objc(MySecureSignalsAdapter)
public class MySecureSignalsAdapter: IMASecureSignalsAdapter {
  static let VersionMajor = 1;
  static let VersionMinor = 0;
  static let VersionPatch = 1;

  private var initError

  override init() {
    super.init()

    do {
      // Initialize your SDK and any dependencies.
      ...
    } catch {
      // Build NSError to be passed by Signal Collector.
      self.initError = ...;
    }
  }

  public func collectSignals(completion: @escaping IMASignalCompletionHandler) {
    if (self.initError) {
      completion(nil, self.initError)
      return
    }

    do {
      // Collect and encrypt the signals.
      var signals = ...
      // Pass the encrypted signals to IMA SDK.
      completion(signals, nil)
    } catch {
      NSError collectSignalError = ...
      // Pass signal collection failures to IMA SDK.
      completion(nil, collectSignalError)
    }      
  }

  public static func adapterVersion() -> IMAVersion {
    let adapterVersion = IMAVersion()
    adapterVersion.majorVersion = self.VersionMajor
    adapterVersion.minorVersion = self.VersionMinor
    adapterVersion.patchVersion = self.VersionPatch
    return adapterVersion
  }

  public static func adSDKVersion() -> IMAVersion {
    // Request the version from your SDK and convert to an IMAVersion.
    let mySDKVersion = ...

    let adSDKVersion = IMAVersion()
    adSDKVersion.majorVersion = mySDKVersion[0]
    adSDKVersion.minorVersion = mySDKVersion[1]
    adSDKVersion.patchVersion = mySDKVersion[2]
    return adSDKVersion
  }
}
```