This is a simple question but one which greatly confuses me. When you have a PKIPKC, the public key can be accessed by anyone. Therefore, doesn't this mean that anyone can encrypt data? My question is basically that if you have such a scheme where the public key is used to encrypt some instructions, the receiver can end up decrypting rogue instructions does it not? In such case, the receiver would need to do some security checks upon decrypting the message.
Looks like the PKI'sPKC's purpose is purely the security of the message itself, and not the actual integrity of data.