|
Article and Writeup Page This section comprises a few of my write ups, mostly fun to read. 01. Attacking the Interlock Protocol. Abstract
The Interlock Protocol is used as a mechanism to foil the Man in the Middle Attack, however by the attack proposed below, it is shown that the Interlock Protocol is insecure. It involves faking the first packet of the communication and the �man in the middle� sending forth half of the (n) th packet when he receives half of the (n+1) th packet and completes the attack. Download: Type PDF, 83 KB 02. Introduction to Diffie-Hellman and its Analog over Elliptic Curves using polynomial basis.
Download: Type PDF, 158 KB | Elliptic Curve Cryptosystem | ecc.pdf | 03. Introduction to Elliptic Curves-A prequel.
Download: Type PDF, 96 KB 04. Man in the Middle Attack on the Analog of Massey Omura over Elliptic Curves
Abstract
The man in the middle attack (MITM) on the analog of Massey Omura over Elliptic curves may look confusing but is trivial and is as discussed.
Download: Type PDF, 54 KB | MITM on analog of Massey Omura | mo-mitm | 05. Cryptanalysis of Linear Congruence Generators
Abstract Multiplicative congruential generators have been first suggested by D.H.Lehmer as an arithmetic procedure to generate pseudo random numbers. A mild variation of it is the linear congruence generator. Over many years both these generators were widely used in simulations and reported to have good statistical properties and favorable cycle length. Cryptanalysts have come up with numerous complex methods to cryptanalyze the generators mentioned above. We present a simple method to cryptanalyze both multiplicative and linear congruence generators, which make them unsuitable as raw input to simulations and various cryptosystem.
Download: Type PDF, 136 KB
| Cryptanalysis of Linear Congruence Generators | lcg.pdf | 06. Mini Project on Secure E-Banking Functionality E-Banking is vulnerable to numerous attacks as it deals with online digital cash transactions. It is hence important to use publicly acclaimed cryptographic algorithms that have been under scrutiny and cryptanalysis for numerous years. We choose a symmetric key cryptosystem such as Blowfish for our implementation. Though encrypted, the transactions between the two banks are still vulnerable to block replay attacks by a man in the middle. To thwart this attack we use a suitable chaining mode such as Cipher Block Chain with checksum (CBCC). A separate Initialization Vector (IV) is generated for chaining each transaction, using a fast Pseudo Random Number Generator (PRNG) with a large period. We use one such PRNG known as Mersenne Twister (MT19937). The public keys of Bank A and Bank B are authenticated by a Certifying Authority (CA). The application is implemented by writing a client and server program using Berkley Sockets. This application assumes the existence of a CA and doesn�t implement any Public Key cryptosystem. Download: Type WinZip, 529 KB(Total) 07. RSA Encryption Algorithm in a Nut Shell Abstract To analyze the RSA encryption algorithm and present a working implementation in python. We discuss the mathematical results and see why the math works. The proofs of various number theoretic results subsequently discussed are available in books mentioned in the bibliography and thus omitted. Detailed discussions on big oh notation, time complexity of basic bit operations, Euclidean and extended Euclidean algorithm, time complexity of Euclidean algorithm, time complexity of extended Euclidean algorithm, linear congruences, Euler totient function, Fermats little theorem, Euler�s theorem, the Miller-Rabin test are presented. With this mathematical background we then analyze the RSA algorithm followed by a simplifed example. Finally, the documented python code for the RSA algorithm is presented and is hoped to be of use for serious programmers who intend on implementing the algorithm on a workstation. (Co-Authored with R.S)
Download: Type PDF, 392 KB
| RSA Encryption Algorithm in a Nut Shell | rs.pdf | 08. Applications to Chinese Remainder Theorem. Abstract
We demonstrate the usefulness of a simple mathematical result- the Chinese Remainder Theorem (CRT). A short informal introduction is followed by a formal analysis of the Chinese Remainder Theorem. Further, we discuss its application to a simple k-threshold system for secret sharing and for clever RSA variants, namely RSA-CRT and Rebalanced-RSA-CRT.Note: The description of k-threshold scheme using chinese remainder theorem is incorrect, please refer to "C.Asmuth, J. Bloom: A modular approach to key safeguarding". IEEE Transactions
on Information Theory 29(2): 208-210 (1983).
Download: Type PDF, 124 KB | Applications to Chinese Remainder Theorem. | crt.pdf | 09. Cryptovirology: Threats and Countermeasures. We describe a less common attack on standalone and networked computer systems known as CryptoViral attacks. These are however very powerful attacks, where the attacker can hold the victim�s data for ransom.
Download: Type PDF, 24 KB | Cryptovirology: Threats and Countermeasures | cv.pdf | 10. Two Cryptanalysis Challenges Based on the Discrete Log Problem. I had the good fortune to write two Crypto Challenges based on the Discrete Log Problem and I thank Nequ Marba for trying them out and solving it correctly. Download: Type PDF, 24 KB 11. Two Other Crytpo Challenges. Two simple challenges-one related to the RSA cryptosystem and the other related to Inverting Matrices.
Download: Type PDF, 12 KB
|
Articles
