Encryption API for Kotlin SDK

PubNub Kotlin SDK includes message and file encryption. This page explains how to configure the cryptoModule and how to encrypt and decrypt data. The SDK supports 128-bit Advanced Encryption Standard (AES) and 256-bit AES in Cipher Block Chaining (CBC) mode (AES-CBC).

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 Kotlin SDK:

Your client can decrypt content produced by either cryptoModule or legacy cipherKey-based encryption. This allows the client to read historical messages and messages from older clients while you encrypt new messages with the stronger AES-256-CBC cipher.

Older SDK versions

Apps built using the SDK versions lower than 7.6.0 will not be able to decrypt data encrypted using the 256-bit AES-CBC cipher. Update your clients or encrypt data using the legacy algorithm.

SDK initialization required

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

Relationship between cryptoModule and cipherKey

The cryptoModule supersedes the cipherKey parameter. If you pass cipherKey (or customCipherKey, where applicable) to a method, that argument overrides the configured cryptoModule for that operation and uses legacy AES-128 encryption. For partial encryption, create a separate cryptoModule instance and use it only where needed.

Encryption methods

Encrypt

Use this function to encrypt data.

Deprecated

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

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

Method(s)

To encrypt the data you can use the following method(s) in Kotlin SDK.

pubnub.encrypt(
    inputString: String,
    cipherKey: String
)

* required

Parameter	Description
inputString * Type: String	The data to encrypt.
cipherKey Type: String	Cipher key to use for encryption. If provided, the legacy encryption with 128-bit cipher-key entropy is used. If not provided, the cryptoModule from PubNub config will be used. For more information, refer to Crypto module configuration.

Sample code

Encrypt part of message

Returns

It returns the encrypted inputString as a String.

Encrypt file input stream

Encrypts input stream with a cipher key.

Deprecated

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

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

Method(s)

pubnub.encryptInputStream(inputStream: InputStream, cipherKey: String)

* required

Parameter	Description
inputStream * Type: InputStream Default: n/a	Stream with content to encrypt.
cipherKey Type: String Default: PNConfiguration.getCipherKey()	If provided, the legacy encryption with 128-bit cipher-key entropy is used. If not provided, the cryptoModule from PubNub config will be used. For more information, refer to Crypto module configuration.

Sample code

Returns

InputStream with encrypted data.

Decryption methods

Decrypt

This function allows to decrypt the data.

Deprecated

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

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

Method(s)

pubnub.decrypt(
    inputString: String,
    cipherKey: String
)

To decrypt the data you can use the following method(s) in Kotlin SDK.

* required

Parameter	Description
inputString * Type: String	The data to decrypt.
cipherKey Type: String	Cipher key to use for decryption.

Sample code

Returns

It returns the decrypted inputString as a String.

Decrypt file input stream

Decrypts input stream with a cipher key.

Deprecated

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

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

Method(s)

pubnub.decryptInputStream(inputStream: InputStream, cipherKey: String)

* required

Parameter	Description
inputStream * Type: InputStream Default: n/a	Stream with content encrypted data.
cipherKey Type: String Default: PNConfiguration.getCipherKey()	Cipher key to use for encryption. If provided, the legacy encryption with 128-bit cipher-key entropy is used. If not provided, the cryptoModule from PubNub config will be used. For more information, refer to Crypto module configuration.

Sample code

Returns

InputStream with decrypted data.