Public Policy and the Internet: How Public Key Encryption Works

Public Policy and the Internet
Course Syllabus

Privacy: How Public Key Encryption Works

Public key encryption depends on the innovation of two encryption keys, one public and one private. The public key is made available for use by others, while the private key is kept secret.

This is called asymmetric encryption.

See also, the page "What is a key?"

Alice Communicating with Bob
Using Public Key Encryption

Step 1: Secrecy and Confidentiality


Alice wants to send a secret message to Bob. Alice learns from Bob that his public encryption key is in a public key directory.		Bob tells Alice where to find his public key, in a directory of public keys.
Alice prepares her message for Bob in plain text.	Alice uses Bob's public key to encrypt her message.	The encrypted message is sent to Bob by Alice, and it is indecipherable to anyone except Bob.
	Bob then uses his private key to decrypt Alice's message. Only Bob's private key can be used to decrypt messages encoded with his public key.	Once the message is decrypted with Bob's private key, he can read it.

Step 2: Authentication (click here)