Presented by: Kevin Hieb May 2, 2005

Transcription

1 Presented by: Kevin Hieb May 2, 2005

2 Governments National Finances National Security Citizens Companies Data Loss Monetary Loss Individuals Identity Theft Data Loss

3 Networks Firewalls Intrusion Detection System (IDS) Software Encryption Company Policies Frequent Password Changes Limiting Access to Sensitive Information Having outside companies review company security

4 Encryption The process of making data unreadable by anyone except the intended recipient.

5 Scytale: Used by the Greeks Enigma: Used by the Germans in World War II

6 Symmetric Algorithms An algorithm where the same key is used to both encrypt and decrypt. Stream Algorithms and Block Algorithms Stream Algorithms Operating on the plaintext one bit at a time. Example: One-time pad Block Algorithms Operate on the plaintext a group/block of bits at a time. Example: DES and AES

7 Asymmetric Algorithms (Public-Key Algorithm) An algorithm where the key for encryption is different than the key for decryption and the decryption key cannot be determined by the encryption key. Public Key and Private Key Public Key Usually referred to as the encryption key. Private Key Usually referred to as the decryption key.

8 In January, 1997 the US National Institute for Security Technologies (NIST) announced that it was developing an encryption to replace DES. They called for public submissions for the new AES algorithm. 15 algorithms were submitted. After evaluation, five finalists were selected. MARS, RC6, Rijndael, Serpent, and Twofish The finalists were then evaluated in the areas of Security, Cost, and Algorithm and Implementation Characteristics. The Rijndael algorithm won.

9 Advanced Encryption Standard (Rijndael) First Published in 1998 by Vincent Rijmen and Joan Daemen Was adopted by the National Institute of Standards and Technology in It is a Block Symmetric Algorithm that supports key sizes of 128, 192, or 256 bits with a block size of 128 bits.

10 AES operates on a 4x4 array of bytes. The 4x4 array is called the state and the AES encryption algorithm performs 4 different operations on the state matrix. SubBytes ShiftRows MixColumns AddRoundKey

11 The AES encryption algorithm performs these steps for a certain number of rounds depending on the key size. 10 rounds for 128 bits 12 rounds for 192 bits 14 rounds for 256 bits The MixColumns step is skipped on the last round.

12 AES vs. Triple-DES Â AES Triple-DES Type of algorithm Symmetric, block cipher Symmetric, feistel cipher Key size (in bits) 128, 192, or 168 Speed High Low Time to crack (assume a machine could try 255 keys per second - NIST) 149 trillion years 4.6 billion years Resource consumption Low Medium

13 Invented by Ron Rivest, Adi Shamir, and Leonard Adleman. The algorithm was first presented in Description: Asymmetric algorithm (public-key algorithm) Chips exist that can perform 1024-bit RSA encryption Slower process than Symmetric algorithms Security comes from the difficulty of factoring large numbers Security has never been proved or disproved First asymmetric algorithm that could be used for encryption and digital signatures.

14 Key Generation Generate two prime numbers, p and q n = p * q m = (p-1)(q-1) e is a small number that is relatively prime to m Find d, such that (d*e) % m = 1 e and n are released as the public key d and n are kept as the secret key

15 Encryption C = P e % n P is the plaintext Decryption P = C d % n

16 p = 11, q = 19 n = p*q = 11*19 = 209 m = (p-1)(q-1) = 10*18 = 180 e = 7 d = 103 Public Key n = 209 e = 7 Private Key n = 209 d = 103

17 Encryption C = P e % n C = % 209 = 194 Decryption P = C d % n P = % 209 = 123

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19 The effectiveness is determined by: People not Security Tools Realize that data security is an important issue Implementation of security procedures

20 Books Applied Cryptography, 2 nd edition by Bruce Schneier Elements of Modern Algebra, 5 th edition by Jimmie and Linda Gilbert Surviving Security, 2 nd edition by Amanda Andress Internet Resources THE ADVANCED ENCRYPTION STANDARD: The development of a new cryptographic standard by CES MSDN Magazine Encrypt It: Keep Your Data Secure with the New Advanced Encryption Standard - by James McCaffrey PAJ s Home: Cryptology: RSA by Paul Johnston Wikipedia

21 Dr. James Kirk For being the Beacon of Light in the darkness that is the uncertainty of Senior Seminar. Mr. Willie George For providing lessons/lectures in the uses of Visual Basic 6.0 and instructing me on topics cover in Abstract Algebra.