getRandomInteger

Generate a random N-bit integer.

Introduction

The getRandomInteger function generates a random integer of N bits. The number is generated by first obtaining a random set of N bits, then ensuring the number is an N-bit intger through extending and masking of the bits. The logic for generating the random bits is similar to the one described in documentation if os.urandom. It uses BcryptGenRandom function from the bcrypt library in Windows and /dev/urandom in Unix-based systems as the randomness source to generate the random bits (refer this). The function can generate integers of any size if the force parameter is set to True. However, for performance reasons, the function is limited to generating integers of size <= 2^18 if force=False.

getRandomInteger(N=1024, force=False)

Parameters:

• N (int) – The number of bits in the generated integer, defaults to 1024. N is asserted to be <= 2^18 for performance reasons.

• force (bool) – If True, the function will generate a random integer of any size, defaults to False for performance reasons.

Returns:

A random integer of N bits

Return type:

int

Example Usage

# Example usage of getRandomInteger to generate a 5-bit integer
from cryptosystems import getRandomInteger
getRandomInteger(5) # 19