Thomas Stütz

A Survey of H.264 AVC/SVC Encryption

Video encryption has been heavily researched in the recent years. This survey summarizes the latest research results on video encryption with a special focus on applicability and on the most widely-deployed video format H.264 including its scalable extension SVC. The survey intends to give researchers and practitioners an analytic and critical overview of the state-of-the-art of video encryption narrowed down to its joint application with the H.264 standard suite and associated protocols (packaging/streaming) and processes (transcoding/watermarking).

A survey on JPEG2000 encryption

Image and video encryption has become a widely discussed topic; especially for the fully featured JPEG2000 compression standard numerous approaches have been proposed. A comprehensive survey of state-of-the-art JPEG2000 encryption is given. JPEG2000 encryption schemes are assessed in terms of security, runtime and compression performance and their suitability for a wide range of application scenarios.

Format-Compliant Encryption of H.264/AVC and SVC

An encryption approach for H.264/AVC and SVC is proposed. Although the bitstream (format stream) is encrypted with state-of-the-art symmetric ciphers, H.264/AVC and SVC compliance is preserved. Standard compliant encoder/decoder and conventional symmetric ciphers, e.g., in specialized hardware, can still be employed - a significant advantage compared to previous work. The approach is suitable for a wide range of application scenarios.

Efficient in-network adaptation of encrypted H.264/SVC content

This paper addresses the efficient adaptation of encrypted scalable video content (H.264/SVC). RTP-based in-network adaptation schemes on a media aware network element (MANE) in an IPTV and VoD scenario are considered. Two basic alternatives to implement encryption and adaptation of H.264/SVC content are investigated: (i) full, format-independent encryption making use of Secure RTP (SRTP); (ii) SVC-specific encryption that leaves the metadata relevant for adaptation (NAL unit headers) unencrypted. The SRTP-based scheme (i) is straightforward to deploy, but requires the MANE to be in the security context of the delivery, i.e., to be a trusted node. For adaptation, the content needs to be decrypted, scaled, and re-encrypted. The SVC-specific approach (ii) enables both full and selective encryption, e.g., of the base layer only. SVC-specific encryption is based on own previous work, which is substantially extended and detailed in this paper. The adaptation MANE can now be an untrusted node; adaptation becomes a low-complexity process, avoiding full decryption and re-encryption of the content. This paper presents the first experimental comparison of these two approaches and evaluates whether multimedia-specific encryption can lead to performance and application benefits. Potential security threats and security properties of the two approaches in the IPTV and VoD scenario are elementarily analyzed. In terms of runtime performance on the MANE our SVC-specific encryption scheme significantly outperforms the SRTP-based approach. SVC-specific encryption is also superior in terms of induced end-to-end delays. The performance can even be improved by selective application of the SVC-specific encryption scheme. The results indicate that the efficient adaptation of SVC-encrypted content on low-end, untrusted network devices is feasible.

On Format-Compliant Iterative Encryption of JPEG2000

Format-compliant encryption of JPEG2000 has attracted researchers for several years. Most benefits of format-compliant encryption result from the preservation of code-stream features, such as scalability. The possibility of reducing the complexity of encryption and to realize transparent encryption schemes are among the additional features of format-compliant selective encryption. Wu and Deng have proposed a format-compliant iterative encryption scheme for JPEG2000 on a CCP basis. In this paper we discuss whether it is possible to extend this approach to packet bodies and give an exact formula for the expected computational effort. The theoretical results are cross-verified by an experimental survey

Non-Blind Structure-Preserving Substitution Watermarking of H.264/CAVLC Inter-Frames

In this work we propose a novel non-blind H.264/CAVLC structure-preserving substitution watermarking algorithm. The proposed watermarking algorithm enables extremely efficient watermark embedding by simple bit substitutions (substitution watermarking). The bit-substitutions change the motion vector differences of non-reference frames. Furthermore our watermarking algorithm can be applied in applications scenarios which require that watermarking preserves the length of the bitstream units (structure-preserving watermarking). The watermark detection works in the image domain and thus is robust to video format changes. The quality and robustness of the approach are in depth evaluated and analyzed, the quality evaluation is backed up by subjective evaluations. Comparison to the state-of-the-art indicates a superior performance of our watermarking algorithm.

Format-compliant JPEG2000 encryption in JPSEC: security, applicability, and the impact of compression parameters

JPEG2000 encryption has become a widely discussed topic and quite a number of contributions have been made. However, little is known about JPEG2000 compression parameters and their influence on the security and performance of format, compliant encryption schemes. In this work, a thorough analysis of this topic is presented with a focus on format-compliant packet body encryption as sketched in the FCD 15444-8 (JPSEC). A proof for the reversibility of JPSEC format-compliant packet body encryption is given. As format-compliant packet body encryption preserves the JPEG2000 headers, which severely compromises the security, we additionally discuss packet header encryption with a special focus on format compliance and the influence of compression parameters on these schemes.

Training of Carbohydrate Estimation for People with Diabetes Using Mobile Augmented Reality

Background: Imprecise carbohydrate counting as a measure to guide the treatment of diabetes may be a source of errors resulting in problems in glycemic control. Exact measurements can be tedious, leading most patients to estimate their carbohydrate intake. In the presented pilot study a smartphone application (BEAR), that guides the estimation of the amounts of carbohydrates, was used by a group of diabetic patients. Methods: Eight adult patients with diabetes mellitus type 1 were recruited for the study. At the beginning of the study patients were introduced to BEAR in sessions lasting 45 minutes per patient. Patients redraw the real food in 3D on the smartphone screen. Based on a selected food type and the 3D form created using BEAR an estimation of carbohydrate content is calculated. Patients were supplied with the application on their personal smartphone or a loaner device and were instructed to use the application in real-world context during the study period. For evaluation purpose a test measuring carbohydrate estimation quality was designed and performed at the beginning and the end of the study. Results: In 44% of the estimations performed at the end of the study the error reduced by at least 6 grams of carbohydrate. This improvement occurred albeit several problems with the usage of BEAR were reported. Conclusions: Despite user interaction problems in this group of patients the provided intervention resulted in a reduction in the absolute error of carbohydrate estimation. Intervention with smartphone applications to assist carbohydrate counting apparently results in more accurate estimations.

Format-compliant jpeg2000 encryption with combined packet header and packet body protection

All proposals for format-compliant encryption schemes for JPEG2000 that have been made to date only encrypt packet body data, but leave packet header data in plaintext. In this paper we show that for providing strict confidentiality, leaving the packet header in plaintext severely compromises the security of these schemes, as discriminative - and for some settings even visual - information can be extracted from the header. We propose a set of format-compliant transformations of the packet header data that confines this information leakage. Furthermore, we discuss to what extent the proposed header protection scheme may be used to increase the performance of partial/selective encryption schemes that, rather than providing full confidentiality, trade off security for a decrease in computational demands.

On efficient transparent jpeg2000 encryption

Efficient (in the sense of computationally efficient as well as efficient from a distribution technology perspective) format-compliant transparent encryption schemes for JPEG2000 are investigated. While the traditional approach of encrypting enhancement layers suffers from high computational encryption demand and drawbacks in distribution, the proposed window encryption approach can reduce computational cost and allows a controlled adaptation of the required security for many application scenarios.