Сrypto

C++ long arithmetic implementation and various numerical algorithms as well as ElGamal cryptosystem.

Long arithmetic

The arithmetic module provides an easy-to-use interface for log arithmetic calculations. The BigInteger has following constructors

BigInteger()            initializes object to represent 0
BigInteger(string)      initializes object to a numeric value represented by string parameter

Once a number object is created, it can be used in arithmetical expressions both with other objects of the type as well as primitive numerical values due to implicit type conversion.

Algorithms

Example of usage:

PollardsRhoFactorization factorization;     create algorithm object
factorization.factorize(BigInteger)         returns vector of prime factors

Currently supported algorithms for the following problems

• Discrete logarithm problem (baby step gigian step)
• Chinese remainder problem
• Discrete square root (Cipolla`s algorithm)
• Primality test (Soloway-Strassen algorithm)
• Computing GCD
• Computing extended GCD
• Computing Euler function
• Computing Mobius function
• Computing Jacobian symbol
• Computing Legendre symbol
• Finding sequence loop (Floyd algorithm)