Search Results (3)

With the increasing amount of cloud-based speech files, the privacy protection of speech files faces significant challenges. Therefore, integrity authentication of speech files is crucial, and there are two pivotal problems: (1) how to achieve fine-grained and highly accurate tampering detection and (2) how to perform high-quality tampering recovery under high tampering ratios. Tampering detection methods and tampering recovery methods of existing speech integrity authentication are mutually balanced, and most tampering recovery methods are carried out under ideal tampering conditions. This paper proposes an encrypted speech integrity authentication method that can simultaneously address both of problems, and its main contributions are as follows: (1) A 2-least significant bit (2-LSB)-based dual fragile watermarking method is proposed to improve tampering detection performance. This method constructs correlations between encrypted speech sampling points by 2-LSB-based fragile watermarking embedding method and achieves low-error tampering detection of tampered sampling points based on four types of fragile watermarkings. (2) A speech self-recovery model based on residual recovery-based linear interpolation (R2-Lerp) is proposed to achieve tampering recovery under high tampering ratios. This method constructs the model based on the correlation between tampered sampling points and their surrounding sampling points and refines the scenarios of the model according to the tampering situation of the sampling points, with experimental results showing that the recovered speech exhibits improved auditory quality and intelligibility. (3) A scrambling encryption algorithm based on the Lorenz mapping is proposed as the speech encryption method. This method scrambles the speech sampling points several times through 4-dimensional chaotic sequence, with experimental results showing that this method not only ensures security but also slightly improves the effect of tampering recovery. Full article

This paper describes a voice encryption device that can be widely used in civil voice call encryption. This article uses a composite encryption method to divide the speech into frames, rearrange them in the time domain, and encrypt the content of the frames. The experimental results show that the device can complete the encryption normally under various analog voice call conditions, and the voice delay, quality, encryption effect, etc. are guaranteed. Compared with traditional time-domain encryption, it effectively solves the original voice information remaining in the encrypted information, and further increases the security of the voice. Full article

This paper presents a method for speech steganography using two levels of security: The first one related to the scrambling process, the second one related to the hiding process. The scrambling block uses a technique based on the ability of adaptation of speech signals to super-Gaussian signals. The security of this block relies on the value of the seed for generating the super-Gaussian signal. Once the speech signal has been scrambled, this is hidden in a non-sensitive speech signal. The hiding process is adaptive and controlled by the value of bits to hold ( $BH$ ). Several tests were performed in order to quantify the influence of $BH$ in the quality of the stego signal and the recovered message. When $BH$ is equal to six, symmetry was found between the modified bits and unchanged bits, and therefore hiding capacity is 50%. In that case, the quality of the stego signal is 99.2% and of the recovered signal is 97.4%. On the other hand, it is concluded that without knowledge of the seed an intruder cannot reverse the scrambling process because all values of the seed are likely. With the above results, it can be affirmed that the proposed algorithm symmetrically considers both the quality of the signal (stego and recovered) as well as the hiding capacity, with a very large value of the key space. Full article