Encryption API for C# SDK

PubNub C# 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 C# 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 6.18.0 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 publish/subscribe keys and a user ID. See the Configuration guide for setup instructions.

Relationship between CryptoModule and cipherKey

The CryptoModule supersedes the cipherKey parameter, providing stronger security and more flexibility. If you pass cipherKey to an API call while CryptoModule is configured, the call uses legacy AES-128 encryption and ignores CryptoModule for that operation. 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 C# SDK.

pubnub.Encrypt(inputString, cipherKey)

* required

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

Sample code

Encrypt part of message

Encrypt file

Use this function to encrypt file content.

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 file you can use the following method(s) in C# SDK.

pubnub.EncryptFile(sourceFile, destinationFile) 
pubnub.EncryptFile(sourceFile, destinationFile, cipherKey)

* required

Parameter	Description
sourceFile * Type: String	File to be encrypted.
destinationFile * Type: String	Path of the encrypted file to be saved.
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. This parameter is deprecated and will be removed in a future version. Please use the CryptoModule from PubNub config instead.

byte[] outputBytes = pubnub.EncryptFile(sourceBytes) byte[] outputBytes = pubnub.EncryptFile(sourceBytes, cipherKey)

* required

Parameter	Description
sourceBytes * Type: byte[]	byte array of the file.
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

Decryption methods

Decrypt

Use this function to decrypt 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 decrypt the data you can use the following method(s) in C# SDK.

pubnub.Decrypt(inputString, cipherKey)

* required

Parameter	Description
inputString * Type: String	The data to decrypt.
cipherKey Type: String	Cipher key to use for encryption. This parameter is deprecated and will be removed in a future version. Please use the CryptoModule from PubNub config instead.

Sample code

Decrypt part of message

Decrypt file

Use this function to decrypt file content.

Method(s)

To decrypt the file you can use the following method(s) in C# SDK.

pubnub.DecryptFile(sourceFile, destinationFile); pubnub.DecryptFile(sourceFile, destinationFile, cipherKey);

* required

Parameter	Description
sourceFile * Type: String	File to be decrypted.
destinationFile * Type: String	Path of the decrypted file to be saved.
cipherKey Type: String	Cipher key to use for decryption. 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.

byte[] outputBytes = pubnub.DecryptFile(sourceBytes) byte[] outputBytes = pubnub.DecryptFile(sourceBytes, cipherKey)

* required

Parameter	Description
sourceBytes * Type: byte[]	byte array of the file.
cipherKey Type: String	Cipher key to use for decryption. 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