Research And Analysis Of LAC Authentication Encryption Algorithm

With the rise of the third scientific and technological revolution,the Internet age is coming.The Internet as the representative of the emerging media is gradually replacing the radio,newspapers,television and other traditional media.Mobile phones,computers and other communication tools are gradually spread throughout the world.Mobile payment and other new payment methods are also gradually occupied the position of traditional currency in the payment market.Mass of information is spread quickly every day.The information itself contains the intrinsic or potential value,but also with the rise of the Internet era and become increasingly high.At this point,the status of information security is particularly important.We not only to protect the security of information,but also to protect the integrity of information,which is a guarantee of the intrinsic value of information.Authentication encryption mode of work is such a password scheme,it can be calculated in the encryption process at the same time to generate authentication tag to protect the user information in the dissemination process of security and integrity.In 2014,Europe launched the CAESAR Competition to identify security and performance standards that are superior to AES-GCM and meet the requirements of security,adaptability and robustness.The competition collects 57 candidate algorithms in the world,most of them are authentication encryption algorithms based on block cipher.In this paper,the security of LAC candidate algorithm is analyzed,and the improvement scheme is given for the defects of its design.In this paper,we use the forgery attack scheme to analyze the LAC authentication encryption algorithm.We first analyze the core LBlock-s lightweight block cipher of the LAC algorithm and find a high probability differential path with 35 active S-boxes,and introduce the search scheme of the differential path.In the subsequent LAC forgery attack,through the forgery of the ciphertext,the adjacent two modules introduce the difference and achieve the collision,so as to obtain the correct tag to achieve the purpose of fraud authenticator.Finally,according to the principle of forgery attack,we find the bugs in the design of LAC algorithm.Then we give the optimization and improvement scheme,which makes the authentication encryption scheme have the function of resisting the forged attack and give the proof of security.