Zafar Shahid

Fast Protection of H.264/AVC by Selective Encryption of CAVLC and CABAC for I and P Frames

This paper presents a novel method for the protection of bitstreams of state-of-the-art video codec H.264/AVC. The problem of selective encryption (SE) is addressed along with the compression in the entropy coding modules. H.264/AVC supports two types of entropy coding modules. Context-adaptive variable length coding (CAVLC) is supported in H.264/AVC baseline profile and context-adaptive binary arithmetic coding (CABAC) is supported in H.264/AVC main profile. SE is performed in both types of entropy coding modules of this video codec. For this purpose, in this paper the encryption step is done simultaneously with the entropy coding CAVLC or CABAC. SE is performed by using the advanced encryption standard (AES) algorithm with the cipher feedback mode on a subset of codewords/binstrings. For CAVLC, SE is performed on equal length codewords from a specific variable length coding table. In case of CABAC, it is done on equal length binstrings. In our scheme, entropy coding module serves the purpose of encryption cipher without affecting the coding efficiency of H.264/AVC by keeping exactly the same bitrate, generating completely compliant bitstream and utilizing negligible computational power. Owing to no escalation in bitrate, our encryption algorithm is better suited for real-time multimedia streaming over heterogeneous networks. It is perfect for playback on handheld devices because of negligible increase in processing power. Nine different benchmark video sequences containing different combinations of motion, texture, and objects are used for experimental evaluation of the proposed algorithm.

Visual Protection of HEVC Video by Selective Encryption of CABAC Binstrings

This paper presents one of the first methods allowing the protection of the newly emerging video codec HEVC (High Efficiency Video Coding). Visual protection is achieved through selective encryption (SE) of HEVC-CABAC binstrings in a format compliant manner. The SE approach developed for HEVC is different from that of H.264/AVC in several aspects. Truncated rice code is introduced for binarization of quantized transform coefficients (QTCs) instead of truncated unary code. The encryption space (ES) of binstrings of truncated rice codes is not always dyadic and cannot be represented by an integer number of bits. Hence they cannot be concatenated together to create plaintext for the CFB (Cipher Feedback) mode of AES, which is a self-synchronizing stream cipher for so-called AES-CFB. Another challenge for SE in HEVC concerns the introduction of context, which is adaptive to QTC. This work presents a thorough investigation of HEVC-CABAC from an encryption standpoint. An algorithm is devised for conversion of non-dyadic ES to dyadic, which can be concatenated to form plaintext for AES-CFB. For selectively encrypted binstrings, the context of truncated rice code for binarization of future syntax elements is guaranteed to remain unchanged. Hence the encrypted bitstream is format-compliant and has exactly the same bit-rate. The proposed technique requires very little processing power and is ideal for playback on hand held devices. The proposed scheme is acceptable for DRM of a wide range of applications, since it protects the contour and motion information, along with texture. Several benchmark video sequences of different resolutions and diverse contents were used for experimental evaluation of the proposed algorithm. A detailed security analysis of the proposed scheme verified the validity of the proposed encryption scheme for content protection in a wide range of applications.

Fast protection of H.264/AVC by selective encryption of CABAC

This paper presents a novel method for the protection of copyrighted multimedia content. The problem of selective encryption (SE) is being addressed along with the compression for the state of the art video codec H.264/AVC. SE is performed in the context-based adaptive binary arithmetic coding (CABAC) module of video codec. For this purpose, CABAC is converted to an encryption cipher. It has been achieved through scrambling of equal length bin strings. In our scheme, CABAC engine serves the purpose of encryption cipher without affecting the coding efficiency of H.264/AVC by keeping exactly the same bit rate, generating completely compliant bitstream and utilizing negligible computational power. Owing to no escalation in bit rate, our encryption algorithm is better suited for real-time multimedia streaming. It is perfect for playback on handheld devices because of negligible increase in processing power. Nine different benchmark video sequences containing different combinations of motion, texture and objects are used for experimental evaluation of the proposed algorithm.

Considering the reconstruction loop for watermarking of intra and inter frames OF H.264/AVC

This paper presents and analyzes a new approach to data hiding that embeds in both the intra- and inter-frames from the H.264/AVC video codec. Most of the current video data hiding algorithms take into account only the intra-frames for message embedding. This may be attributed to the perception that inter-frames are highly compressed due to the motion compensation, and any embedding message inside these may adversely affect the compression efficiency significantly. Payload of the inter-frames is also thought to be less, compared with the intra-frames, because of the lesser residual data. We analyze data hiding in both intra- and inter-frames over a wide range of QP values and observe that the payload of the inter is comparable with that of the intra-frames. Message embedding, in only those non-zero quantized transform coefficients (QTCs) which are above a specific threshold, enables us to detect and extract the message on the decoding side. There is no significant effect on the overall bitrate and PSNR of the video bitstream because instead of embedding message in the compressed bitstream, we have embedded it during the encoding process by taking into account the reconstruction loop. For the non-zero QTCs, in the case of intra-frames, we benefit from the spatial masking, while in the case of inter-frames, we exploit the motion and texture masking. We can notice that the data hiding is done during the compression process and the proposed scheme takes into account the reconstruction loop. The proposed scheme does not target robustness and the obtained payload is higher, with a better trade-off in terms of quality and bitrate, as compared with previous works.

FAST PROTECTION OF H.264/AVC BY SELECTIVE ENCRYPTION

This paper presents a novel method for the protection of copyrighted multimedia content. The problem of selective encryption (SE) has been addressed alongwith compression for the state of the art video codec H.264/AVC. SE is performed in the context-based adaptive binary arithmetic coding (CABAC) module of video codec. For this purpose, CABAC is converted to an encryption cipher by scrambling of equal length binarized code words. In our scheme, CABAC engine serves the purpose of encryption cipher without affecting the coding efficiency of H.264/AVC by keeping the original bitrate, generating completely compliant bitstream and utilizing negligible computational cost. Nine different benchmark video sequences containing different combinations of motion, texture and objects have been subjected to experimental evaluation of the proposed algorithm.

Selective and scalable encryption of enhancement layers for dyadic scalable H.264/AVC by scrambling of scan patterns

This paper presents a new selective and scalable encryption (SSE) method for intra dyadic scalable coding framework based on wavelet/subband (DWTSB) for H.264/AVC. It has been achieved through the scrambling of quantized transform coefficients (QTCs) in all the subbands of DWTSB. To make the encryption scalable, it takes advantage of the prior knowledge of the frequencies which are dominant in different high frequency (HF) subbands, as traditional zigzag scan is not that efficient for them. Thus, by scrambling the scan order of QTCs in the intra scalable coding framework of H.264/AVC, we were able to get encryption and compression for enhancement layers (ELs) simultaneously. Watermarking has been integrated in the proposed architecture to avoid the requirement of separate keys for each spatial layer. The algorithm is better suited for multimedia streaming as the bitrate of the encrypted bitstream is lower than the original bitrate. Besides offering SSE, the proposed algorithm, when applied to different benchmark video sequences, outperformed the standard zigzag scan in terms of bitrate.

Spread spectrum-based watermarking for Tardos code-based fingerprinting for H.264/AVC video

In this paper, we present a novel approach for active finger-printing of state of the art video codec H.264/AVC. Tardos probabilistic fingerprinting code is embedded in H.264/AVC video signals using spread spectrum watermarking technique. Different linear and non-linear collusion attacks have been performed in the pixel domain to show the robustness of the proposed approach. The embedding has been performed in the non-zero quantized transformed coefficients (QTCs) while taking into account the reconstruction loop.

H.264/AVC video watermarking for active fingerprinting based on Tardos code

In this paper, we present a novel approach for active fingerprinting of state-of-the-art video codec H.264/AVC. Tardos probabilistic fingerprinting code is embedded in H.264/AVC video signals using spread spectrum watermarking technique in both luma and chroma. Tardos code is embedded in intra as well as inter frames. The embedding has been performed in the nonzero quantized transformed coefficients, which are above a certain threshold while taking into account the reconstruction loop, to avoid the uncontrollable increase in bitrate of video bitstream. A comprehensive analysis of payload and PSNR trade-off is presented for the benchmark video sequences. Different linear and nonlinear collusion attacks have been performed in the pixel domain to show the robustness of the proposed approach.

Selective encryption of C2DVLC of AVS video coding standard for I & P frames

In this paper, a novel method for fast protection of AVS video coding standard alongwith compression is presented. Here the problems of compression and selective encryption (SE) have been simultaneously addressed for AVS part-2 Jizhun profile. It is performed in the context-based 2D variable length coding (C2DVLC) module of video codec. SE is performed by using the Advanced Encryption Standard (AES) algorithm with the Cipher Feedback (CFB) mode on a subset of codewords. C2DVLC serves the purpose of encryption step without affecting the coding efficiency of AVS by keeping the bitrate unchanged, generating completely compliant bitstream and utilizing negligible computational power. Nine different benchmark video sequences containing different combinations of motion, texture and objects are used for experimental evaluation of the proposed algorithm.

Independent Protection of Different Layers in Spatially Scalable Video Coding

Abstract In this paper, a novel method for independent access of different layers of protected scalable video coding (SVC), based on framework of state of the art H.264/AVC, is presented. For a SVC bitstream, a user accessing the base layer needS only one key while users accessing the enhancement layer need keys for both the base layer and enhancement layer. Hence if a user is accessing the highest available layer, keys of all the lower layers are also needed to decode it properly. We have devised a scheme in which the user accessing any particular resolution use only one key whether it is the base layer or any of the enhancement layers, and all the keys have the same length. Advanced encryption standard (AES) algorithm in Cipher Feedback (CFB) mode has been used in this scheme to make the keys secure. The scheme has been tested both for offine playback and online streaming environment. Five different benchmark video sequences having three resolutions and containing different combinations of motion, texture and objects are used for experimental evaluation of the proposed algorithm.