A fine-grained reversible data hiding in encrypted domain based on the cipher-text redundancy of encryption process

Area of Science:

• Computer Science
• Information Security
• Cryptography

Background:

• Effective management of multi-granularity information requires sophisticated reversible data hiding schemes.
• Encrypted data in cloud environments has limited application possibilities due to access control challenges.

Purpose of the Study:

• To propose a fine-grained reversible data hiding method for ElGamal encrypted data.
• To enhance permission control and management of multi-granularity information in cloud environments.

Main Methods:

• Organizing pixels into a full binary tree based on access permissions.
• Utilizing a chaotic sequence generator for embedding keys per layer.
• Employing XOR operations for secret information embedding.
• Iterative manipulation of the random variable during ElGamal encryption for feature alignment.

Main Results:

• Successful embedding and extraction of secret information with three granularities without interference.
• Achieved a maximum embedding capacity of up to 1.75 bits per pixel (bpp).
• Demonstrated fine-grained blind extraction of secret information from encrypted data.

Conclusions:

• The proposed method expands the application of encrypted data by enabling information extraction without data decryption.
• Enhanced information security through distributed storage and concealed information hiding.
• The scheme effectively supports multi-granularity information management in cloud settings.