文档介绍：曹天杰
Tianjie Cao
******@cumt.
College puter Science and
Technology, China University of Mining and Technology, Xuzhou, China
中国矿业大学计算机科学与技术学院
Block ciphers-AES Advanced Encryption Standard
1
Security
Software
Efficiency
Hardware
Efficiency
Flexibility
Origins of AES
2
Additional key-sizes and block-sizes
Ability to function efficiently and securely in a wide
variety of platforms and applications
low-end smartcards, wireless: small memory requirements
IPSec, ATM – small key setup time in hardware
B-ISDN, munication – large encryption speed
Flexibility
3
15 Candidates
from USA, Canada, Belgium,
France, Germany, Norway, UK, Israel,
Korea, Japan, Australia, Costa Rica
June 1998
August 1999
October 2000
1 winner: Rijndael
Belgium
5 final candidates
Mars, RC6, Rijndael, Serpent, Twofish
Round 1
Round 2
Security
Software efficiency
Flexibility
Security
Hardware efficiency
AES Contest 1997-2001
4
AES
In 1999, NIST issued a new standard that said 3DES should be used
168-bit key length
Algorithm is the same as DES
3DES had drawbacks
Algorithm is sluggish in software
Only uses 64-bit block size
In 1997, NIST issued a calls for proposals for the new Advanced Encryption Standard (AES)
security strength >= 3DES
improved efficiency
must be a symmetric block cipher (128-bit)
key lengths of 128, 192, and 256 bits
5
AES Evaluation
Criteria used by NIST to evaluate potential candidates
Initial Criteria:
Security
Cost
Algorithm characteristics
Final Criteria:
General Security
Software Implementations
Restricted-space environments
Flexibility
Hardware Implementations
Attacks on Implementations
Encryption vs. Decryption
Key agility
6
NESSIE Project
New European Schemes for Signatures,
Integrity, and Encryption
2000-2002
CRYPTREC Project
2000-2002
Europe
Japan
7
Multiple types of transformations:
Development of methodology of a fair evaluation parison of algorithms belonging to the same class, including
software and hardware effici