How to accept input into array

I have a server and client. The client will send a message, which is encrypted, to the server and the server will decrypt it. If the message block size is more than one, it will only send the last letter to the server to decrypt. I am trying to use array but am not sure how the server will be able to get t开发者_如何学运维o decrypt the message as it will only get the last letter. Can someone please help?

Answering this:

am not sure how the server will be able to get to decrypt the message as it will only get the last letter

The server can't decrypt your message because it doesn't have enough information. You can be sure of it.