Encryption Audio Signal with IDEA Technique Enhanced by Chaotic System

Block encryption using the International Data Encryption Algorithm (IDEA) is strong, efficient, and widely used, but brute force attackers can exploit its 128-bit key space. This paper proposes the integration of chaotic (Hanon Map) key generation into the conventional International Data Encryption Algorithm (IDEA) for voice encryption to increase the key space and incorporate nonlinearity to Henon map subkey generation. The Henon map, a chaotic sequence, and permuting the extended IDEA key bits make the IDEA key schedule appropriate for audio encryption and resistant to cryptanalytic attacks. We verify the method’s security using differential and linear cryptanalysis. Results show chaotic key generation greatly improves IDEA audio encryption security. The expanded key space and nonlinearity protect sensitive audio data from cipher breaks. The simulation results of voice encryption based on IDEA and chaos indicate that the mean squared error is very close to one, the correlation is very close to zero, and the signal-to-noise ratio is greater than zero. Employing a Henon chaotic system expands the key space from 128 bits to 327 bits.