Data Compression Using New Fast Adaptive Cosine–Haar Transforms

Morháč, M.; Matoušek, V.

doi:10.1006/dspr.1997.0301

Cited by 5 publications

(1 citation statement)

References 17 publications

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“…They are computationally efficient and powerful tools of digital signal processing which find wide application in, e.g., compression, filtering, and encryption of data [24][25][26][27][28][29][30][31][32]. FPOTs usually adopt the computational structures of known transforms with determined basis vectors.…”

Section: Fast Parametric Orthogonal Transformsmentioning

confidence: 99%

Joint compression and encryption of visual data using orthogonal parametric transforms

Puchala¹,

Yatsymirskyy²

2016

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. In this paper, we introduce a novel method of joint compression and encryption of visual data. In the proposed approach the compression stage is based on block quantization while the encryption uses fast parametric orthogonal transforms of arbitrary forms in combination with a novel scheme of intra-block mixing of data vectors. Theoretical analysis of the method indicates no impact of encryption stage on the effectiveness of block quantization with an additional step of first order entropy coding. Moreover, a series of experimental studies involving natural images and JPEG lossy compression standard were performed. Here, the obtained results indicate a high level of visual content concealment with only a small reduction of compression performance. An additional analysis of security allows to state that the proposed method is resistant to cryptanalytic attacks known for visual data encryption schemes including the most efficient NZCA attack. The proposed method can be also characterized by high computational efficiency and feasibility of hardware realizations. In the view of the above motivation, we propose in this paper a novel method for joint compression and encryption of visual data. In the proposed approach the compression stage uses block quantization, which is the core of existing standards such as: JPEG, MJPEG and MPEG. It allowed to keep compliance with known standards and to obtain comparable performance of data compression. The encryption process is based on fast parametric orthogonal transforms (FPOTs) and a novel scheme of inter-block mixing of data vectors. The proposed method can be characterized by higher combinatorial complexity than existing methods based on linear transforms and, in addition, it is resistant to cryptanalytic attacks known for visual data encryption algorithms.In the research part of the paper it was proved theoretically that the proposed encryption scheme does not affect the compression performance based on block quantization with an additional step of first order entropy coding. Furthermore, a series of experiments concerning joint compression and encryption of natural images were performed by embedding the proposed encryption scheme into JPEG standard. Finally, we discuss in detail the aspects of computational complexity of the method and also provide a critical analysis of its resistance to the known types of cryptanalytic attacks. Existing visual data encryption methodsThe existing methods of visual data encryption can be divided into two groups: naive and selective. The naive approach

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