Cipher

About: Cipher is a research topic. Over the lifetime, 9409 publications have been published within this topic receiving 110309 citations. The topic is also known as: cypher & cryptographic algorithm.

Method and system for updating certification key

Abstract: The invention is to solve issues: not security of transferring authentication cipher key through network by using plaintext; and managing bother, and high cost by using cryptograph format to transfer authentication cipher (AC). The disclosed method for updating AC remotely includes steps: server end calculates random seed and random number to generate verification data; server end carries out encryption operation for original AC and verification data, and transfers random seed and result of encryption operation to client end; information security equipment validates correctness of random seed; carrying out same encryption operation for random seed and original AC inside the information security equipment, and at server end so as to generate new AC, which is in use for updating AC inside the information security equipment, and database in server. The invention also discloses system for updating AC.

Fruit-80: A Secure Ultra-Lightweight Stream Cipher for Constrained Environments

Abstract: In Fast Software Encryption (FSE) 2015, while presenting a new idea (i.e., the design of stream ciphers with the small internal state by using a secret key, not only in the initialization but also in the keystream generation), Sprout was proposed. Sprout was insecure and an improved version of Sprout was presented in FSE 2017. We introduced Fruit stream cipher informally in 2016 on the web page of IACR (eprint) and few cryptanalysis were published on it. Fortunately, the main structure of Fruit was resistant. Now, Fruit-80 is presented as a final version which is easier to implement and is secure. The size of LFSR and NFSR in Fruit-80 is only 80 bits (for 80-bit security level), while for resistance to the classical time-memory-data tradeoff (TMDTO) attacks, the internal state size should be at least twice that of the security level. To satisfy this rule and to design a concrete cipher, we used some new design ideas. It seems that the bottleneck of designing an ultra-lightweight stream cipher is TMDTO distinguishing attacks. A countermeasure was suggested, and another countermeasure is proposed here. Fruit-80 is better than other small-state stream ciphers in terms of the initialization speed and area size in hardware. It is possible to redesign many of the stream ciphers and achieve significantly smaller area size by using the new idea.

Dynamic cipher certifying system and method

Abstract: The system includes interface at client end, authentication server, database, management server, and dynamic token containing individual information of user The method includes steps: dynamic token authenticates user ID; after authentication of user ID is passed, dynamic token generates dynamic cipher based on time/event factors and built-in individual information of user as well as combination with cipher key calculation; through interface at client end, user transfers dynamic cipher to authentication server; after receiving dynamic cipher, and obtaining individual information of user through calculation, the authentication server authenticates dynamic cipher In the invention, user only needs to input current generated dynamic cipher to carry out log on authentication so as to raise performance of easy to use in dynamic cipher authentication mode The invention also protects privacy of individual information of user

Analysis of the statistical cipher feedback mode of block ciphers

Abstract: In this paper, we examine a recently proposed mode of operation for block ciphers which we refer to as statistical cipher feedback (SCFB) mode. SCFB mode configures the block cipher as a keystream generator for use in a stream cipher such that it has the property of statistical self -synchronization, thereby allowing the stream cipher to recover from bit slips in the communication channel. Statistical self-synchronization involves feeding back ciphertext to the input of the block cipher similar to the conventional cipher feedback (CFB) mode, except that the feedback only occurs when a special synchronization pattern is recognized in the ciphertext. In the paper, we examine the efficiency, resynchronization, and error propagation characteristics of SCFB and compare these to conventional modes such as CFB and output feedback (OFB). In particular, we study these characteristics of SCFB as a function of the synchronization pattern size. As well, we examine implementation issues of SCFB, focusing on the buffer requirements and resulting delay for a practical realization of the cipher. We conclude that SCFB mode can be used to provide practical, efficient, self-synchronizing implementations for stream ciphers. In particular, SCFB mode is best used in circumstances where slips are a concern and where implementation efficiency is a high priority in comparison to encryption latency.

Symmetric key cryptosystem using combined cryptographic algorithms - Generalized modified Vernam Cipher method, MSA method and NJJSAA method: TTJSA algorithm

Abstract: In the present paper the authors have introduced a new combined cryptographic method called TTJSA. Nath et al. have already developed some symmetric key methods. In the present work the authors have used two methods MSA and NJJSAA which were developed by Nath et al. and have developed a new algorithm, generalized modified Vernam Cipher Method. The above three methods are applied in random order on any given plain text for a number of times to get the ultimate cipher text file. In the present work, authors modified the standard Vernam Cipher Method for all characters (ASCII code 0–255) with randomized keypad, and have also introduced a feedback mechanism. The method has been closely monitored on different known plain text and it was found that this method is almost unbreakable. The present method allows multiple encryption/decryption. The present method is an extremely secure block cipher method and it can be applied to encrypt data in Defense system, Banking sector, mobile network etc. The advantage of the present method is that one can apply this method on top of any other standard algorithm such as DES, AES or RSA. The method is suitable to encrypt any type of file.