Encryption API for Unreal SDK

You can use PubNub's functionality via Blueprints or directly in C++ code.

• In Blueprints, the SDK is managed by a subsystem. Start by calling the Pubnub Subsystem node, then use Create Pubnub Client to create a UPubnubClient instance.

• In a C++ project, you have to add a dependency to PubnubLibrary:

  1. In your IDE, navigate to Source/_{YourProject}_/_{YourProject}_.Build.cs and add a dependency to PubnubLibrary.

     PrivateDependencyModuleNames.AddRange(new string[] { "PubnubLibrary" });

  2. Compile the code and run the project.

• In C++, start by getting the UPubnubSubsystem (a Game Instance Subsystem), then create a UPubnubClient with your configuration.

  #include "Kismet/GameplayStatics.h"
  #include "PubnubSubsystem.h"
  #include "PubnubClient.h"
  
  
  UGameInstance* GameInstance = UGameplayStatics::GetGameInstance(this);
  UPubnubSubsystem* PubnubSubsystem = GameInstance->GetSubsystem<UPubnubSubsystem>();
  
  
  FPubnubConfig Config;
  Config.PublishKey = "pub-c-...";
  Config.SubscribeKey = "sub-c-...";
  Config.UserId = "my-user-id";
  
  
  UPubnubClient* PubnubClient = PubnubSubsystem->CreatePubnubClient(Config);

  PubnubClient allows you to call PubNub SDK functions, for example:

  PubnubClient->PublishMessageAsync("my-channel", "Hello!", OnPublishMessageResponseDelegate);

  The SDK supports multiple UPubnubClient instances within the same game for different contexts such as different users or keysets. For more information, refer to Configuration.

Usage in Blueprints and C++

Synchronous API

Encryption methods (SetCryptoModule, GetCryptoModule) are synchronous only; there are no async variants. Configure the crypto module on each UPubnubClient when using the Client API. When using multiple clients, each client has its own crypto module.

PubNub Unreal SDK includes message encryption. This documentation covers crypto module configuration and utility methods for encrypting and decrypting messages using both legacy 128-bit and enhanced 256-bit AES-CBC encryption.

For general SDK configuration and initialization, refer to the Configuration page.

Configuration

The crypto system in Unreal SDK consists of three main components:

1. Cryptors (IPubnubCryptorInterface), which are individual encryption algorithms (AES, Legacy)
2. Provider interface (UPubnubCryptoModule), which is the top-level interface used by each PubNub client.
3. Crypto module (IPubnubCryptoProviderInterface), which manages multiple cryptors with automatic algorithm selection.

To configure the crypto module for a client so that all messages are encrypted, use SetCryptoModule and GetCryptoModule on the UPubnubClient instance. When using multiple clients, set the crypto module on each client that should use encryption.

Automatic message encryption/decryption

Once configured, the crypto module automatically handles encryption and decryption:

• All published messages are encrypted using the default cryptor
• Received messages and fetched history messages are automatically decrypted using the appropriate cryptor (determined by the 4-byte identifier in the message header)

Set crypto module

Sets the crypto module for this client. All messages published or received by this client will use this module for encryption and decryption.

1PubnubClient->SetCryptoModule(TScriptInterface<IPubnubCryptoProviderInterface> CryptoModule);

* required

Parameter	Description
CryptoModule * Type: TScriptInterface<IPubnubCryptoProviderInterface>	The crypto module object that implements IPubnubCryptoProviderInterface. Use UPubnubCryptoModule for the default PubNub encryption implementation.

Returns

This method does not return a value.

Sample code

To set the crypto module and configure AES encryption/decryption for all messages for this client:

C++

Actor.h

1

Actor.cpp

1

Blueprint

Get crypto module

Returns the crypto module currently set for this client.

1TScriptInterface<IPubnubCryptoProviderInterface> CryptoModule = PubnubClient->GetCryptoModule();

Returns

Type	Description
TScriptInterface<IPubnubCryptoProviderInterface>	The crypto module previously set with SetCryptoModule() for this client. Returns an empty interface if none was set.

Sample code

To get the crypto module for the current client:

C++

Actor.h

1

Actor.cpp

1

Blueprint

Available cryptors

The Unreal SDK provides two built-in cryptor implementations:

AES cryptor (UPubnubAesCryptor)

Uses 256-bit AES-CBC encryption with PKCS#7 padding. This is the recommended cryptor for new applications.

Feature	Description
Identifier	'A', 'C', 'R', 'H' (4-byte header identifier)
Key management	Set cipher key using SetCipherKey(FString)
IV generation	Generates random 16-byte IV for each encryption
Compatibility	Compatible with PubNub AES encryption across all SDKs

Legacy cryptor (UPubnubLegacyCryptor)

Provides compatibility with older PubNub encryption implementations while encrypting messages with the AES cryptor. Use the AES cryptor if you don't need to decrypt legacy messages.

Legacy cryptor usage

Useful when your Unreal SDK must be able to decrypt messages encrypted with the legacy PubNub encryption from other SDKs.

Feature	Description
Identifier	{0, 0, 0, 0} (4-byte legacy identifier)
Key management	Set cipher key using SetCipherKey(FString)
IV options	Supports both random IV (default) and fixed IV modes
Compatibility	Compatible with legacy PubNub encryption

Legacy configuration

To configure legacy decryption for all messages:

Actor.h

1

Actor.cpp

1

Custom cryptors

To use a custom cryptor, you need to implement the IPubnubCryptorInterface interface. For more information, refer to the Data security section.

Encrypt

This function allows you to encrypt data manually using the configured crypto module.

Method(s)

To encrypt data you can use the following method in the Unreal SDK:

IPubnubCryptoProviderInterface::Execute_ProviderEncrypt(CryptoModule, Message);

* required

Parameter	Description
CryptoModule * Type: UObject*	The crypto module object that implements IPubnubCryptoProviderInterface.
Message * Type: FString	The plaintext data to encrypt.

Sample code

Actor.h

1

Actor.cpp

1

Other examples

Encrypt using a module set during configuration

Actor.h

1

Actor.cpp

1

Returns

Returns the encrypted message as a Base64-encoded FString or an empty string if encryption fails.

Decrypt

This function allows you to decrypt data manually using the configured crypto module.

Method(s)

To decrypt data you can use the following method in the Unreal SDK:

IPubnubCryptoProviderInterface::Execute_ProviderDecrypt(CryptoModule, EncryptedMessage);

* required

Parameter	Description
CryptoModule * Type: UObject*	The crypto module object that implements IPubnubCryptoProviderInterface.
EncryptedMessage * Type: FString	The Base64-encoded encrypted data to decrypt.

Sample code

Actor.h

1

Actor.cpp

1

Other examples

Decrypt using a module set during configuration

Actor.h

1

Actor.cpp

1

Returns

Returns the decrypted message as a plaintext FString or an empty string if decryption fails.

Set crypto module (deprecated)

Deprecated

Use PubnubClient->SetCryptoModule() instead. Crypto configuration is per client when using the Client API.

1PubnubSubsystem->SetCryptoModule(TScriptInterface<IPubnubCryptoProviderInterface> CryptoModule);

* required

Parameter	Description
CryptoModule * Type: TScriptInterface<IPubnubCryptoProviderInterface>	The crypto module object that implements IPubnubCryptoProviderInterface.

Get crypto module (deprecated)

Deprecated

Use PubnubClient->GetCryptoModule() instead. Each client has its own crypto module when using the Client API.

1PubnubSubsystem->GetCryptoModule();

Returns

Returns the crypto module object that implements IPubnubCryptoProviderInterface which was set using SetCryptoModule() on the default client. If no crypto module was set, returns an empty interface.

Complete example

Reference code

Set up your Unreal project and follow the instructions in the lines marked with ACTION REQUIRED before running the code.

ASample_CryptoFull.h

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ASample_CryptoFull.cpp

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