Variable size key cipher and method and device using the same

Abstract

An encryption device and method and decryption device and method which implement a bit-based encryption scheme and hardware design. The encryption device includes a random number generator, receiving a main key, determining a working key using at least one random number and outputting a working key, a model, receiving the main key, the working key and plain text to be encoded and generating at least two frequency counts. The encryption device further includes an encoder, which outputs encoded text based on the working key, the plain text and the at least two frequency counts. The encryption device and method and decryption device and method progress encrypted text that is based upon a stream structure with an unlimited key length and may be compressed by 50%. The encoded text is changeable with different environments even for the same plain text and the same key. Operations of the hardware design are based on arithmetic additions and shifts, and not multiplications and divisions. As a result, the hardware design is simple and applicable to cryptography and e-commerce.

Description

[0001] The present invention is directed to encryption and decryption, and more particularly, to a variable size key cipher and method and device for utilizing variable size key cipher to perform encryption and decryption.DESCRIPTION OF THE RELATED ART[0002] Traditionally, compression and cryptography have been considered distinct and separate technologies, which were developed and applied separately. However, they share a common goal of removing redundancy of an output, although they do so in different ways. Recognizing this common goal, Witten, Neal and Cleary (hereafter known as WNC) were the first to apply adaptive arithmetic coding to encryption. In particular, WNC made the following observations:[0003] by re-coding messages, compression protects the messages from casual observers;[0004] removing redundancy denies a cryptanalyst the leverage of exploiting the normal statistical regularities in natural language; and[0005] adaptively taking advantage of the characteristics of the...

AI Technical Summary

Benefits of technology

[0014] A bit-based encryption scheme and hardware design of the present invention produces a cipher that is based upon stream structure and with an unlimited key length. The cipher also has the advantage that it may compress plain text by at least 50%. The cipher is changeable with different environment even for the same plain text and the same key. Operations in the hardware design are based on arithmetic additions and shifts, no multiplication and divisions are included. Therefore, the hardware design is simple. The cipher, encoder, decoder and methods are applicable to cryptography and e-commerce.

Problems solved by technology

445-461, 1992, has shown that there are security issues with the WNC scheme.

As a result, it is difficult to design a secure model and key control for the WNC encryption scheme.

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