File implicit transfer method based on public switched telephone network

Abstract

The invention discloses a file implicit transfer method based on a public switched telephone network. The method comprises the following steps: embedding a ciphertext code into a video frequency band according to a preset embedding rule, and generating an amplitude value of the video frequency band containing the ciphertext code; performing IFFT (Inverse Fast Fourier Transform) transform to the amplitude value of the video frequency band containing the ciphertext code, and generating a ciphertext-carried voice; receiving the ciphertext-carried voice by a receiving terminal, extracting synchronization information according to the synchronization algorithm, and determining a synchronization point position, so as to determine the starting position of ciphertext information embedding; performing framing and IFFT transform to the ciphertext-carried voice from the starting position of the ciphertext information embedding, and obtaining the amplitude value of the framed ciphertext-carried voice frequency band; and extracting the ciphertext code according to an extracting rule matched with the preset embedding rule, so as to code an error correcting code to the ciphertext code to generate a secret file. With the adoption of the file implicit transfer method based on the public switched telephone network, wiretapping is not easy.

Description

technical field [0001] The invention relates to a method for hidden transmission of files based on a public switched telephone network, which is a method for designing a hidden transmission system for files aimed at the application environment of a public switched telephone network (PSTN). Background technique [0002] With the rapid development of multimedia technology and the maturity of computer networks, various information media, such as voice and image communication, are becoming more and more common, which will inevitably bring about the problem of communication information security. At present, the telephone has been widely used in the world, and using the PSTN to carry out voice communication has become a very common way of communication in people's daily life. For a deliberate eavesdropper and a malicious saboteur, the public switched telephone network becomes one of their most preferred and easiest objects to attack. [0003] A secure phone is a way of securing a...

AI Technical Summary

Problems solved by technology

[0010] Applying the voice information hiding technology on the PSTN network, some algorithms have been proposed at home and abroad, but there are still great challenges in resisting AD / DA conversion, telephone channel noise, A-law companding, transmission efficiency and call effect. There is room for improvement, but currently there is no public product of the file transmission system based on the public switched telephone network PSTN that does not affect the normal conversation between the two parties.

Images