How to share two private keys ,while anyone else is listening in on the conversation : <p>Cryptographic hashing is a very useful concept. The MD varieties are no longer sufficiently secure--you can break them in reasonable time using Amazon cloud. We use SHA-512 for our superuser password.</p>

<p>While we're on cryptography, you should explain how 2 people can share a completely private key while anyone else is listening in on the conversation. That is the basis of all security on the Internet.</p>
