Page 94 - 2024-Vol20-Issue2

90 | Shumran & Al-Hussein

Fig. 4. Lorenz chaotic Attractor. for chaotic flow is responsible for this process. This study’s
objectives were:

1) Learn about the properties of chaotic systems
and use chaos to create safe communication schemes.

2) Create a two-level security system based on
Lorenz’s chaotic flow and chaotic map to encrypt
voice signals.

3) Apply a non-coherent detection receiver to the
signal that is masked by chaos. That is, creating
a synchronization algorithm that is effective for
chaotic sequences at both the transmitter and the
receiver.

4) Utilizing MATLAB simulations, assess how
well the suggested system performs in the presence
of noise.
Fig. 6.displays the suggested system’s block dia-
gram. Initially, the speech signal is encrypted using
a chaotic map method that has start circumstances
that are understood by the sender and the recipient.
The disorganized speech will be covered up in the
second phase by a disorganized flow signal. A syn-
chronized version of the chaotic signal is initially
used at the receiver side to remove the mask. After
that, the voice recovery and demystification are car-
ried out appropriately.

Fig. 5. Roessler chaotic Attractor. 2) Discrete-time Chaotic Systems (maps):
All the previous encryption methods depend on continuous
dx = -y - x (3) systems, in the following other methods will be reviewed
dt based on discrete chaotic systems that may provide simpler
dy digital realization.
In 2016, Mohamoud F. El Zaher et al [22], introduced a voice
= x + ay encryption system based on substitution and permutation of
dt voice signal depends on secret keys that generated by utilizing
dz = b + z(x - c) the Henon and Arnold Cat maps. First, the speech signal
dt is converted from 1D to 2D then using the Arnold cut map
shown in the Fig. 7. it’s used to permute the blocks and return
Where a, b , c are the system parametersa and the state vari- to the 1D format and use the henon map as a masking key.
ables in this case are x , y and z. Two scenarios are used to generate the mask key: the first one
In 2018, Saad S. Hreshee et al. [21], the suggested system is uses the Henon map, and the second uses a modified Henon
creating a two-level encrypted high-security system. Informa- map to alter the initial parameter. The analysis and the results
tion permutation, or scrambling, is the first stage. The chaotic show that the key size of the proposed secret key is about
map system is used to carry out this procedure. Masking of 10128.
jumbled information is the second level. The Lorenz system
1) The two equations that represent the double-
dimensional chaotic system are known as the Arnold