I have configured a webhook on an external system, the payload I’m receiving is :

{action=updated, data=eyJpdiI6ImJLeURnZklsMFcrdWpEMjYrZzFkMGc9PSIsInZhbHVlIjoiZy9lM3lXZkNBaHA0MFVwVlFDT3BUSVpIaWxrbTBLS213cGtVazQwU2dYTGZsc0s1eXpXMGhpbXYwUTdqSkRTc2ZQTXdrUlZvS1ZTU0piNlpybUN0eGxDRHcwUHh4Nkw0aklsUEhWSFdQcXYyRTl5RTZzNm9VRDgwNjFONExneGoiLCJtYWMiOiJmNTkwNzRhNTk3MTc0NTY1OGYwNWNjYjA0YWJjODAyZjVmNTYzYjExZDljY2JjOTI3NjBlZGZkZjc3NGRkNzEyIiwidGFnIjoiIn0=, id=7657, table=demographics}

and the secret key on the webhook UI is : WCPDMPxUon4u5kwZrw1LKG3oak4av64mlfEt4mgeF5w=

I believe the data field is encrypted.
After messaging the developer of the external system that is sending the payload, all they can tell me is this:

*Our developer team has confirmed that Open SSL is used to encrypt and decrypt the webhook requests. They’ve also mentioned that there’s a second layer using the cipher algorithm:

‘cipher’ => ‘AES-256-CBC’,

I hope this information is helpful to you.*

I have tried to decrypt this but keep getting errors related to the key not being the correct size.

What are the steps to decrypt this payload?

I tried decrypting and got errors saying the secret key was not the right size