How to cancel or delete a signed/authorized public key? (Revocation of public key)
If I have signed a key from Public key authority or public key certificate how can I cancel it?
And here some pictures which shows how public key authority and public key certificate works
In the environment you described and illustrated in your question, in order to initiate a encrypted comunication, the Initiator has to encrypt the data with the Responder public key, so when the Responder receives a message, will be able to decrypt it with its private key.
So the authorities described in the diagrams, play the roles of public-key distribution, and trust authority, confirming that users are really who they say they are. This means that by uploading a public key or sign ing a public certificate with these authorities, you are just providing other users/machines a mechanism to comunicate with you in a secure maner.
If you want to cancel that public key/certificate from being available, or in other words, prevent your key/certificate to be available to anyone to initiate a secure comunication with you, is the authority who has control over it, becasue it lies in their database, and this is why, you should ask them to revoke the key or the certificate.