## Secure Shell

- Ubuntu help for OpenSSH
- Useful implementations
- The standards

## Using SSH and SFTP

SSH is another program that uses keys. Try out the following command:

ssh www.cs.unca.eduTo enable ssh and sftp login without password, try out the following commands. (See the answer in this ubuntu answer for more information.)

ssh-keygen ssh-copy-id www.cs.unca.edu

## Two flavors

- Symmetric
- Asymmetric
- RSA
- RSA as munition
- encrypt, decrypt
*and*sign (using hashes) - Key exchange

## Public key infrastructure

- Public key infrastructure
- Certificate authorities
- Mozilla Inclusive CA Certification List
- Viewing certificates in your browser

## PGP and its frenemies

- Phil Zimmermann
- How PGP works
- OpenPGP specification
- Concepts — private key, public key, passphrase, fingerprint
- GPG, GnuPG, GNU Privacy Guard
- Key signing party
- GPG documents and examples
- GPG Mini Howto
- The GNU Privacy Handbook
- GPG cheat sheet, somewhat dated
- stuff I did to get my key for this course
- stuff I did to get my key for Spring CSCI 107

## Stuff to do

- Generate a GPG public/private key for yourself
- Publish your public key at
`http://www.cs.unca.edu/~`

`yourid`/`yourid`-pub.txt - Insert my key into your key chain
- Generate a
*signed*and*encrypted*message for me - Decrypt a
*signed*and*encrypted*message from me

You will need to generate your public key before I can send you a message.

## Videos for home viewing

- Khan Academy — Modern Cryptography
- Essentials of Cryptography and Network Security — Lynda video
- How asymmetric encryption works — very simply
- RSA Cipher Explained
- Encryption and HUGE numbers - Numberphile
- How the RSA algorithm works, including how to select d, e, n, p, q, and φ (phi)
- How SSL works tutorial - with HTTPS example or SSL TLS HTTPS process explained in 7 minutes