Use a chaotic map (e.g., Logistic map, Tent map, etc.) to generate the chaotic sequence. Chaotic sequences are sensitive to initial conditions and parameters, so choose your initial values and parameters carefully.
For instance, the Logistic map is defined by the equation: xn+1=r⋅xn⋅(1−xn)x_{n+1} = r \cdot x_n \cdot (1 - x_n)xn+1=r⋅xn⋅(1−xn) where rrr is the control parameter, and xnx_nxn is the sequence value at iteration nnn.
2. Normalize the Sequence:
The generated chaotic sequence usually takes values in the range [0, 1] or [-1, 1]. Normalize the sequence to fit within the range of 0 to 1 if needed.
3. Convert the Sequence to a Bit Stream:
Convert the chaotic sequence into a binary bit stream. If you need 10-bit values, you can map the normalized chaotic sequence to 10-bit integers (0 to 1023).
For each value xnx_nxn in the sequence: bn=int(xn×1024)b_n = \text{int}(x_n \times 1024)bn=int(xn×1024) where b_n is the 10-bit representation of the chaotic sequence value.
4. Concatenate the Bit Stream:
Concatenate the binary representation of each b_n to form a bit stream.
Ensure that each sequence is of length 1,000,000 bits. You might need to repeat or truncate the sequence accordingly.
5. Repeat for Multiple Sequences:
Repeat the above steps to generate multiple (e.g., 10) bit streams, each of length 1,000,000 bits, for testing.
Example in Python:--------------------------------------------------------
import numpy as np
def logistic_map(x, r, n):
sequence = []
for i in range(n):
x = r * x * (1 - x)
sequence.append(x)
return sequence
def chaotic_bit_stream(x0, r, n, bit_length):
sequence = logistic_map(x0, r, n)
bit_stream = ''
for x in sequence:
# Map to 10-bit integer
b = int(x * (2 ** bit_length))
# Convert to binary and pad to 10 bits
b_bin = format(b, f'0{bit_length}b')
bit_stream += b_bin
# Stop if we reach the desired length
if len(bit_stream) >= n:
break
return bit_stream[:n]
# Parameters
x0 = 0.7 # Initial condition
r = 3.7 # Control parameter
n = 1000000 # Length of each bit stream
bit_length = 10 # Length of bit representation
# Generate the bit stream
bit_stream = chaotic_bit_stream(x0, r, n, bit_length)
print(f"Bit Stream Length: {len(bit_stream)}")
# Repeat for multiple streams
bit_streams = [chaotic_bit_stream(x0 + i * 0.01, r, n, bit_length) for i in range(10)]