Transcript Slides
Public-Key Cryptology An Asymmetrical Approach to Encryption Overview • Symmetric Cryptology • Asymmetric Cryptology • Digital Signature • Public-Key Utilization • Output of Typical Java Public-Key Encryption Program • Security Discussion • Q&A Symmetric Cryptology • A (unlocked); B(locked) • A > B (Locking) • B > A (Unlocking) Digital Signature • A, C (Locked); B (Unlocked) • A > B > C (Private Key) • C > B > A (Public Key) 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. Java Program Output • Keys are just very large integers. (BigIntegers) • This program utilizes the BigInteger class to make keys. • Output on next slide. Output Plaintext: Yellow and Black Border Collies Ciphertext:98366169821666534826450063721974641305126855986244466880382092 59229811715639585877358783636599416258581268159312178855357078473798790 63785221972057646569713856029262994789186363296799212839124642592911879 60489476483399671979444102724330132229445648838259857452031970574802924 29589977355320433224626523346630 Plaintext: Yellow and Black Border Collies 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. 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 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