Title: Cryptography Cryptography
1CryptographyCryptography
- Brought to you by
- Shannon Burke
2Brief History of Cryptography!!!!
- What is Cryptography?
- Science of writing secret code
- The first use of cryptography in 1900 B.C.
- Used by Egyptian scribe
- Some experts say it appeared right after writing
was invented
3Cryptography Broken Down!!!
- Two kinds of cryptosystems
- Symmetric
- Uses the same key (the secret key) to encrypt and
decrypt a message. - Asymmetric
- Uses one key (the public key) to encrypt a
message and a different key (the private key) to
decrypt the message.
4Symmetric Cryptosystem!
- The message
- The sender and receiver know and use the same
secret key. - The sender uses the secret key to encrypt the
message. - The receiver uses the same secret key to decrypt
the message.
5Symmetric Cryptosystem!
Saflslkafskflsakflsdfjfdlkajfkdjafksjdljkasldskf
jfffffffffffffffffffffffffffffkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkk
6Symmetric Challenge!
- Main challenge
- Agreeing on the key while maintaining secrecy.
- Trusting a phone system or some transmission
medium. - The interceptor can read, modify, and forge all
messages
7Key Management!!!
- Key management
- The generation, transmission, and storage of a
key. - All cryptosystems must deal with key management
issues - Because all keys must remain secret there is
often difficulty providing secure key management.
8Introduction of the Public Key!!!
- Created to solve key management problems.
- Created by Whitfield Diffie and Martin Hellman in
1976. - Also called asymmetric system.
- Encryption key public key
- Decryption key private key
9How its works!!!!
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
kkkkkkkkkkkkkkkk
10Lets see some examples!!!!
- Click here to experiment with different
encryption methods. - http//www.cs.usask.ca/resources/tutorials/csconce
pts/1999_3/lessons/L3/SimpleEncryption.html
11A Little Quiz to Test What You Learned!!!
- 1.)What are the two different types of
cryptosystems? - 2.)What is the difference between the two
systems? - Which system was created as a result of
difficulties of the other? What was the
difficulty?
12Your Grade!!!
- Everyone Passed!!!!!
- Thanks for your attention and participation!!!!!!
13Bibliography!!!!
- Cryptography World. 2002. http//www.cryptographyw
orld.com/index.htm - Kessler, Gary. An Overview of Cryptography. May
1998. http//www.garykessler.net/library/crypto.ht
ml - Litterio, Francis. Cryptography.
http//world.std.com/franl/crypto.html - RSA Laboratories. 2004. http//www.rsasecurity.com
/rsalabs/node.asp?id2155