How to decrypt pubnub messages in pubnub blocks - pubnub

Question

Im using pubnub encrypted messages https://www.pubnub.com/docs/javascript/api-reference-sdk-v4#init via cipher key between two clientes, now i start intercepting those messages with PubNub BLOCKS but can't find a way to decrypt them, i receive a long Base64 string and there is no tool to decrypt it via either the provided crypto module or the provided pubnub module, the block is super simple
export default (request) => {
console.log(request); // Log the request envelope passed when tested with a payload its shown when a real message goes through is a base64 string of an encrypted message
return request.ok();
}

Answer 1

Publishing Unencrypted Meta Data with Encrypted Message Paylaod
Currently, if you are using AES encryption the assumption is that you would want end to end encryption and not be able to decrypt the message in-flight by a BLOCK.
However if there is information you want to act on, you pass the information using the Meta Argument. This meta information is outside the message payload and not encrypted and therefore accessible by a BLOCK.
The PubNub PM team would love to hear more about your use case and why you would want to decrypt this message in flight to see if this is something we need to add to the roadmap. Please send a message to PubNub Support with more details.
Here is some sample code you can use to see the meta data in action with a block:
Publishing a message with meta data
The meta data portion of your message is never encrypted and it meant for data that you would use for filtering messages (and other use cases). If you are using an cipher key when you init PubNub, the message portion of the payload would be encrypted from end to end (not decrypted within PubNub since we do not know your cipher key). But the meta portion would remain clear text so that you can perform condition logic in a block based on these keys/values or for stream filtering on a per client basis.
pubnub.publish(
{
channel : "chmeta",
message : {"text": "hello"},
meta: {
"cool": "beans"
}
},
function(status, response) {
console.log(status, response);
}
);
Accessing meta data with PubNub BLOCKS
In your block code (Before or After Publish event handlers), you can access the meta key as follows:
export default (request) => {
console.log(JSON.parse(request.params.meta));
return request.ok();
}
The output of the entire request parameter would be quite verbose and I encourage you to review it as it will have lots of gems in there you might want to take advantage of, but just honing in on the meta key (request.params.meta) will give access to the meta data you provided in the publish. The JSON.parse is needed because the data will be stringified (escaped), {\"cool\": \"beans\"}, and this will transform it back into a real live JSON object, {"cool": "beans"}.

Answer 2

Okay, I did it myself. The code is ugly and I am open to any help with refactoring, but it works - it lets you decrypt messages in PubNub functions (blocks)
Here's the Gist - https://gist.github.com/DataGreed/f0007e7b5b8dcfadd8a44a5d3514b6dc
Don't forget to change the encryption key in getKey function.

Answer 3

PubNub Functions (formerly called BLOCKS) now has Crypto Module
I believe at the time you asked this question, the crypto module was not included with BLOCKS (we rebranded this as PubNub Functions). Now it is:
PubNub Functions Crypto Module Docs