packet - Is there a public / private key encryption scheme that will not change a message's length? -

Is there a public / private key encryption scheme that will not change the length of the message?

Once a message is encrypted like a packet, but if the packet grows, it will not be just a packet long.

This is a simple plan: use public / private key encryption to install a symmetric key . Then do all your encryption using that symmetric key.

If you need to integrate the message and reject the message, then you can run the message through a hash function, which gives it a fixed length. Then you can sign the hash.

Usually, you will not want to use the public key in any way to encrypt messages. Compared to public encryption, public / private key pairs are harder and more expensive to generate than

.