Encryption API for Dart SDK

PubNub Dart SDK provides built-in message and file encryption to secure your real-time communications. This documentation covers crypto module configuration and utility methods for encrypting and decrypting files using both legacy 128-bit and enhanced 256-bit AES-CBC encryption.

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

Configuration

cryptoModule configuration

To configure the cryptoModule to encrypt all messages/files, you can use the following methods in the Dart SDK:

// encrypts using 256-bit AES-CBC cipher (recommended)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
var cryptoModule = CryptoModule.aescbcCryptoModule(CipherKey.fromUtf8('enigma'));

// encrypts with 128-bit cipher key entropy (legacy)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
var cryptoModule = CryptoModule.legacyCryptoModule(CipherKey.fromUtf8('enigma'));

// partial encryption
// create cryptoModule
var cryptoModule = CryptoModule.aesCbcCryptoModule(CipherKey.fromUtf8('abcd'));

// encrypt normal message
var encrypted = cryptoModule.encrypt('Hello'.codeUnits);

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Your client can decrypt content encrypted using either of the modules. This way, you can interact with historical messages or messages sent from older clients while encoding new messages using the more secure 256-bit AES-CBC cipher.

Older SDK versions

Apps built using the SDK versions lower than 4.2.4 will not be able to decrypt data encrypted using the 256-bit AES-CBC cipher. Make sure to update your clients or encrypt data using the legacy algorithm.

SDK Initialization required

Before using encryption methods, ensure your PubNub client is properly configured with subscribe key and user ID. See the Configuration guide for setup instructions.

Encryption methods

Encrypt file

Encrypts file content in bytes format.

Deprecated

The cipherKey parameter in this method is deprecated. We recommend that you configure a separate instance of the crypto module and use it for partial encryption.

If you pass cipherKey as an argument, it overrides the crypto module configuration and the legacy encryption with 128-bit cipher key entropy is used.

Method(s)

pubnub.files.encryptFile(
  List<int> bytes,
  {CipherKey? cipherKey,
  Keyset? keyset,
  String? using}
)

* required

Parameter	Description
bytes * Type: List<int>	File content in bytes.
cipherKey Type: cipherKey	A cipherKey to override Keyset.cipherKey. For more information, refer to Configuration.
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.

Sample code

// create cryptoModule
var cryptoModule = CryptoModule.aesCbcCryptoModule(CipherKey.fromUtf8('abcd'));

// encrypt file data   NOTE: same method because it works at byte level
var encryptedFileData = cryptoModule.encrypt(fileData);

Returns

Byte List of encrypted data.

Decryption methods

Decrypt file

Decrypts file content in bytes format.

Deprecated

The cipherKey parameter in this method is deprecated. We recommend that you configure a separate instance of the crypto module and use it for partial encryption.

If you pass cipherKey as an argument, it overrides the crypto module configuration and the legacy encryption with 128-bit cipher key entropy is used.

Method(s)

pubnub.files.decryptFile(
  List<int> bytes,
  {CipherKey? cipherKey,
  Keyset? keyset,
  String? using})

* required

Parameter	Description
bytes * Type: List<int>	File content in bytes.
cipherKey Type: cipherKey	A cipherKey to override Keyset.cipherKey. For more information, refer to Configuration.
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.

Sample code

// create cryptoModule
var cryptoModule = CryptoModule.aesCbcCryptoModule(CipherKey.fromUtf8('abcd'));

// encrypt file data   NOTE: same method because it works at byte level
var encryptedFileData = cryptoModule.encrypt(fileData);

// decrypt file data 
var decryptedFileData = cryptoModule.decrypt(encryptedFileData);

// create file again from decrypted file bytes
File('decryptedFile.jpg').writeAsBytesSync(decryptedFileData);

Returns

Byte list of decrypted data.