Crypto vs Code

Cryptography is the study of mathematical techniques related to aspects of information security such as confidentiality, data integrity, entity authentication, and data origin authentication. [Handbook of Applied Cryptography – Alfred J. Menezes Paul C. van Oorschot Scott A. Vanstone]

Coding is needed for efficient reliable digital transmission and storage. [Error Control Coding – Shu Lin, Daniel J. Costello]. Coding theory is is the study of the properties of codes and their fitness for a specific application. Codes are used for data compression, cryptography, error-correction and more recently also for network coding. Codes are studied by various scientific disciplines—such as information theory, electrical engineering, mathematics, and computer science—for the purpose of designing efficient and reliable data transmission methods. This typically involves the removal of redundancy and the correction (or detection) of errors in the transmitted data. [Wikipedia]

How to Select Cryptographic Key Size?

A good article offering guidelines for the determination of key sizes for symmetric cryptosystems, RSA, and discrete logarithm based cryptosystems both over finite fields and over groups of elliptic curves over prime fields.

It can be downloaded here.

Is this random enough?

Setting up curves with different numbits for ElGamal

This book and the software is very useful for doing experiments of encrypting using elliptic curve cryptography. I’ve been reading some thread with questions on how to change curve parameters, and here’s how:

To change the number of bits, you have to set it in field2n.h

Choose the polynomial irreducible in polymain.c

Set the message to be encrypted in elgamal.c (important note: the length of the message depends on the numbits of the curve)

Now reading

Click to access statja(2010)1.pdf

Simple FSM

—————————————————–
— FSM for multiplier
— CG – 21 Jan 2011
—————————————————–

library ieee ;
use ieee.std_logic_1164.all;

—————————————————–

entity fsm_multiplierCG_1 is
port(
A0,A1,A2,A3: in bit_vector(1 downto 0);
opA : out bit_vector(1 downto 0);
clock: in std_logic;
reset: in std_logic
);
end fsm_multiplierCG_1;

—————————————————–

architecture FSM of fsm_multiplierCG_1 is

— define the states of FSM model

type state_type is (S0, S1, S2, S3);
signal next_state, current_state: state_type;

begin

— cocurrent process#1: state registers
state_reg: process(clock, reset)
begin

if (reset=’1′) then
current_state <= S0;
elsif (clock’event and clock=’1′) then
current_state <= next_state;
end if;

end process;

— cocurrent process#2: combinational logic
comb_logic: process(current_state, clock)
begin

— use case statement to show the
— state transistion

case current_state is

when S0 => opA <= A0;
next_state <= S1;

when S1 => opA <= A1;
next_state <= S2;

when S2 => opA <= A2;
next_state <= S3;

when S3 => opA <= A3;
next_state <= S0;

end case;

end process;

end FSM;

—————————————————–

 

299 classic multiplier

… took forever to compile, and does not fit.

the super long code generated using perl. with the help of master shifu, thank you 🙂

Now reading

Mapping an Arbitrary Message to an Elliptic Curve when Defined over GF(2^n), Brian King, Indiana University – Purdue University Indianapolis 723 W Michigan, SL 160 Indianapolis, IN 46202International Journal of Network Security, Vol.8, No.2, PP.169–176, Mar. 2009.

Now reading

1. Implementation Aspects of Elliptic Curve Cryptography & An Introduction to Unified (Dual-Field) Arithmetic, Erkay Savas, Oregon State University (pdf)
2. Elliptic Curve Cryptosystems on Reconfigurable Hardware, Martin Christopher Rosner, Master Thesis, Worcester Polytechnic Institute, May 2008 (pdf)
3. Fast Algorithms for Elliptic Curve Cryptosystems over Binary Finite Field, [Published in K. Y. Lam and E. Okamoto, Eds., Advances in Cryptology – ASIACRYPT ’99, vol. 1716 of Lecture Notes in Computer Science, pp. 75–85, Springer-Verlag, 1999.], Yongfei Han, Peng-Chor Leong, Peng-Chong Tan, and Jiang Zhang (pdf)

Key Lengths – Arjen K. Lenstra

Key Lengths – Contribution to The Handbook of Information Security, Arjen K. Lenstra Lucent Technologies and TechnischeUniversiteit Eindhoven 1 North Gate Road, Mendham, NJ 07945-3104, U.S.A., June 30, 2004