Through rigorous mathematical analysis, we first investigate the SER of PN-ASK as a function of the channel then, we find the optimal PN-ASK parameters that optimize primary and covert throughput under different channel condition. This way, covert information will be undetectable, since a receiver expecting phase-modulated symbols will see their shift in amplitude as an effect of channel/path loss degradation. Therefore, the residual capacity can be leveraged to implement a wireless system based on a pseudo-noise asymmetric shift keying (PN-ASK) modulation, where covert symbols are mapped by shifting the amplitude of primary symbols. To address this research gap, we notice that existing wireless technologies rely on phase-keying modulations (e.g., BPSK, QPSK) that in most cases do not use the channel up to its Shannon capacity. Existing approaches are protocol-specific and thus their performance cannot be assessed and optimized in general scenarios. Another core issue is to make sure that the covert channel is almost undetectable by eavesdroppers. Since the addition of covert information inevitably decreases the SNR of the primary transmission, a key challenge in wireless steganography is to mathematically analyze and optimize the impact of the covert channel on the primary channel as a function of different channel conditions. To address this issue, wireless steganography 'hides' covert information inside primary information by slightly modifying the transmitted waveform such that primary information will still be decodable, while covert information will be seen as noise by agnostic receivers. If you want to append a file type not directly supported by File Juicer, you can compress it with Finder to a zip file which File Juicer knows how to pull out.Undetectable wireless transmissions are fundamental to avoid eavesdroppers or censorship by authoritarian governments. Most file types can be used this way, except text files which cannot get attachments appended in this way.

You cannot edit it with any photo editing application and expect the secret attachment for be kept there. You get the PDF out again by dropping the JPEG on File Juicer. The JPEG which comes out of File Juicer can be emailed or put on a web site with its hidden load. You can drop more than one file this way. Release the alt-key and drop the PDF onto File Juicer, and it will be appended to the JPEG.File Juicer will keep it in memory until more files are dropped in. Hold down the alt-key while dropping the JPEG image onto File Juicer.To attach a PDF file on the end of a JPEG image follow this recipe An attached message can be read - if you know it is there. This is not the same as encryption where you make it obvious that there is a secret message.

An ordinary JPEG file can carry extra information like a PDF file attached to its end, and most applications will just treat it as an ordinary JPEG image.

Steganography app for mac