Steganography: Hiding messages
* invisible ink
* microdots
* pin code
* microdots

Simple Transposition

* Caesar cypher (ROT)
* "Picket Fence"
* PigPen, dancing man.

Polyalphabetic
* Vigenere square
* Playfair
* Enigma

Cryptanalysis
* Al-Kindi - 5th century
Frequency analysis
* Babbage - Statistic analysis
* Turing - Mechanized

DES: Digital Encryption Standard
* 1976 Officially released
* 1986 First commercial use was HBO
* 1992 First known attack
* 1994 First successful attack
* 1998 56 hours to break a key
* 1999 deprecated for 3DES
* 2001 AES Advanced Encryption Standardized
* 2006 FPGA based machine cracks DES in 9 days
* 2008 1 day
* 56 bit = 100,000,000,000,000,000 keys. (NSA required restriction)

Diffie and Hillmen met in 1970s, both struggling with the key distribution problem

* Hillman had the padlock breakthrough
* Diffie had the idea for asymmetric encryption
* First presented in 1976
* Patented in 1977
* Public key is the encrypting one
* Private key is the decrypting one

RSA: Rivest, Shamir, Adleman implemented the public key

* Essentially, take two prime numbers, P and Q multiply them together and publish the resultant N
* Turns out that if N is sufficiently large, P & Q cannot be determined
* to do so, you have to factor for N (trying each prime).
* With an N at 10^130, on a 1999 era PC - 50 years
* 100 million PC (1999) 15 seconds
* 10^308, 1000 years
* Not invulnerable. Figure out how to factor faster, and you will break it. 2000 years have so far passed without having done this yet.
* 1977 a challenge was announced. It took 600 volunteers 17 years to crack the N. 10^129

PGP: Phil Zimmermann was a bit of a rebel.
* RSA was really designed for large companies with big computers.
* PGP sped up the process with a couple of short cuts
* Utilizes IDEA as well
* Also incorporated the idea of digital signature
* Stuck a pretty interface on it that anyone could use
* PGP violated the RSA patent and got smoked by Congress

OpenSSL
* It is the public release of the RSA(DSA) encryption model
* Prior to the release of OpenSSL, you had to hack the security into web servers

Elliptic Curve
* Asymmetric encryption
* Rather than using the math of prime numbers, it uses the algebraic structure of elliptic curves over finite fields
* Elliptic curve cryptography algorithms entered wide use in 2004 to 2005
* Right now the only approved curves are NSA/NIST
* In August, 2015, NSA announced that it planned to transition "in the not distant future" to a new cipher suite that is resistant to quantum attacks. "Unfortunately, the growth of elliptic curve use has bumped up against the fact of continued progress in the research on quantum computing, necessitating a re-evaluation of our cryptographic strategy."

Quantum Encryption
* Like most discoveries, it has been around a long time. Original research was done in 1799.
* The magic is that photons passing through a slit and hitting a plane create a unique pattern. If you very the slit pattern, you get a different resultant pattern.
* The result is a unique, encryption that is very hard to break.
* Currently, like most things, it is very hard to create inexpensively.