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Analysis of RC6 Symmetric Encryption Algorithm. Heyan Huang. Overview. History What is RC6 Algorithm Strengths & Weaknesses Demonstration Summary. History of RC6. Developed in 1998 for the Advanced Encryption Standard (AES) competition Derivative of RC5
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Analysis of RC6 Symmetric Encryption Algorithm Heyan Huang
Overview • History • What is RC6 • Algorithm • Strengths & Weaknesses • Demonstration • Summary
History of RC6 • Developed in 1998 for the Advanced Encryption Standard (AES) competition • Derivative of RC5 • Met all 3 criteria for the competition: “high security, exceptional simplicity, and good performance.” [Robshaw] • AES Competition 5 Finalists: • Rijndael: 86 positive, 10 negative • Serpent: 59 positive, 7 negative • Twofish: 31 positive, 21 negative • RC6: 23 positive, 37 negative • MARS: 13 positive, 84 negative [Wikipedia]
NIST Comments “Each of the finalist algorithms appears to offer adequate security, and each offers a considerable number of advantages. Any of the finalists could serve admirably as the AES. However, each algorithm also has one or more areas where it does not fare quite as well as some other algorithm; none of the finalists is outstandingly superior to the rest.” – Nechvatal, Barker, Bassham, Burr, Dworkin, Foti, Roback
Features of RC6 • Symmetric key block cipher • Combines simplicity with security • 128 bit block size • Key sizes 128, 192 & 256 bits • 20 round iteration • Supports various word-lengths, key sizes and number of rounds • Works well with 32 bit systems
Features of RC6 • Data-dependent rotations, modular addition and XOR operations • Rotation depends on every bit in a word, not the least significant bits.
Strengths • Most susceptible to brute force attacks, so a key length of 20+ is recommended. [Contini] Figure 3: “Estimates of the Plaintext Requirements to Attack RC6” (Contini 1998)
Weaknesses • Less than 20 rounds would still be susceptible. • Aimed to operate on 32-bit systems, weak on 8-bit processors. • Performance profile on 64-bit machines was volatile.
Summary • History • Algorithm • Encryption • Decryption • Demonstration • Strengths & Weaknesses
Bibliography • R.L. pavan, M.J.B. Robshaw, R.Sidney, and Y.L. Yin. The RC6 Block Cipher. v1.1, August 1998. • Wikipedia: http://en.wikipedia.org/wiki/RC6 • M.J.B. Robshaw (2001, Jan 9), “RC6 and the AES”, retrieved from ftp://ftp.rsasecurity.com/pub/rsalabs/rc6/rc6%2Baes.pdf • J. Nechvatal, E. Barker, L. Bassham, W. Burr, M. Dworkin, J. Foti, and E. Roback. Reprot on the Development of the Advanced encryption Standard (AES). October 2, 2000.