pip install pylfsr
Download the repository or clone it with git, after cd in directory build it from source with
python setup.py install
# import LFSR
import numpy as np
from pylfsr import LFSR
L = LFSR()
# print the info
L.info()
5 bit LFSR with feedback polynomial x^5 + x^2 + 1
Expected Period (if polynomial is primitive) = 31
Current :
State : [1 1 1 1 1]
Count : 0
Output bit : -1
feedback bit : -1
L.next()
L.runKCycle(10)
L.runFullCycle()
L.info()
state = [0,0,0,1,0]
fpoly = [5,4,3,2]
L = LFSR(fpoly=fpoly,initstate =state, verbose=True)
L.info()
tempseq = L.runKCycle(10)
L.set(fpoly=[5,3])
L = LFSR(fpoly=[23,18],initstate ='random',verbose=True)
L.info()
L.runKCycle(10)
L.info()
seq = L.seq
Reference : http://www.partow.net/programming/polynomials/index.html
L = LFSR()
# list of 5-bit feedback polynomials
fpoly = L.get_fpolyList(m=5)
# list of all feedback polynomials as a dictionary
fpolyDict = L.get_fpolyList()
L.changeFpoly(newfpoly =[23,14],reset=False)
seq1 = L.runKCycle(20)
# Change after 20 clocks
L.changeFpoly(newfpoly =[23,9],reset=False)
seq2 = L.runKCycle(20)
Reference Article: Enhancement of A5/1: https://doi.org/10.1109/ETNCC.2011.5958486
# Three LFSRs initialzed with 'ones' though they are intialized with encription key
R1 = LFSR(fpoly = [19,18,17,14])
R2 = LFSR(fpoly = [23,22,21,8])
R3 = LFSR(fpoly = [22,21])
# clocking bits
b1 = R1.state[8]
b2 = R1.state[10]
b3 = R1.state[10]
Folder : https://github.com/Nikeshbajaj/Linear_Feedback_Shift_Register/tree/master/matlabfiles
Description Genrate randon binary sequence using LFSR for any given feedback taps (polynomial), This will also check Three fundamental Property of LFSR
- Balance Property
- Runlength Property
- Autocorrelation Property
This MATLAB Code work for any length of LFSR with given taps (feedback polynomial) -Universal, There are three files LFSRv1.m an LFSRv2.m, LFSRv3.m
This function will return all the states of LFSR and will check Three fundamental Property of LFSR (1) Balance Property (2) Runlength Property (3) Autocorrelation Property
s=[1 1 0 0 1]
t=[5 2]
[seq c] =LFSRv1(s,t)
This function will return only generated sequence will all the states of LFSR, no verification of properties are done here. Use this function to avoid verification each time you execute the program.
s=[1 1 0 0 1]
t=[5 2]
[seq c] =LFSRv2(s,t)
seq = LFSRv3(s,t,N) this function generates N bit sequence only. This is faster then other two functions, as this does not gives each state of LFSR
s=[1 1 0 0 1]
t=[5 2]
seq =LFSRv3(s,t,50)
- If you want to use this function in middle of any program, use LFSRv2 or LFSRv1 with verification =0.
- If you want to make it fast for long length of LFSR,use LFSRv3.m
If any doubt, confusion or feedback please contact me
- Nikesh Bajaj
- http://nikeshbajaj.in
- n.bajaj@qmul.ac.uk
- bajaj[dot]nikkey [AT]gmail[dot]com