1. Public-Key Cryptology An Asymmetrical Approach to Encryption

2. Overview Symmetric Cryptology Asymmetric Cryptology Digital Signature Public-Key Utilization Output of Typical Java Public-Key Encryption Program Security Discussion Q&A

3. Symmetric Cryptology A (unlocked); B(locked) A > B (Locking) B > A (Unlocking)

4. Digital Signature A, C (Locked); B (Unlocked) A > B > C (Private Key) C > B > A (Public Key)

5. Public-Key Utilization Reverse of the digital signature method. Public key is used first. C > B > A (Public Key) A > B > C (Private Key) Only the person with the private key can access this message.

6. Java Program Output Keys are just very large integers. (BigIntegers) This program utilizes the BigInteger class to make keys. Output on next slide.

7. Output Plaintext: Yellow and Black Border Collies Ciphertext:98366169821666534826450063721974641305126855986244466880382092 59229811715639585877358783636599416258581268159312178855357078473798790 63785221972057646569713856029262994789186363296799212839124642592911879 60489476483399671979444102724330132229445648838259857452031970574802924 29589977355320433224626523346630 Plaintext: Yellow and Black Border Collies

8. Brute Force The only guaranteed method for decrypting an encrypted message without a key is through a brute-force method. Test every integer until it matches the correct key. Use the found BigInteger to decrypt the message. This can take a considerable amount of time. Thus, public-key encryption is extremely secure.

9. References http://en.wikipedia.org/wiki/Public-key_cryptography https://www.comodo.com/resources/small-business/digital-certificates2.php http://www.webopedia.com/TERM/P/public_key_cryptography.html http://computer.howstuffworks.com/encryption3.htm

10. Image References http://1.bp.blogspot.com/-X2116y6RLGI/TnnGt5QXjUI/AAAAAAAAAWU/wD-erptNO5E/s1600/symmetric+encryption.gif http://atozdigitalstore.com/images/IC42508.gif https://i-msdn.sec.s-msft.com/dynimg/IC21919.gif