KED-AES algorithm: combined key encryption decryption and advance encryption standard algorithm

Received Nov 21, 2018 Revised Jan 16, 2019 Accepted Feb 1, 2019 Two existing cryptosystems are being combined and proposed. It is the enhanced combination of KED (Key Encryption Decryption), a cryptosystem that uses modulo 69 and the AES (Advance Encryption Standard) cryptography. The strength of the KED is that the keys are being used by the sender and the receiving end. The AES is easy to implement and has good defense against various attacks such as hacking.


INTRODUCTION
Cryptography is the science of encrypting and decrypting information. It is the art of securing data or information by transforming it into another unreadable format wherein a message is hidden from anyone who will read it and only the intended receiver will be able to convert it and reveal the hidden message. The main goal of cryptography is to secure the data from illegal access [1,2].
Based on [3,4], it stated that Cryptography is the scientific establishment on which one forms secure frameworks. It contemplates methods for safely putting away, transmitting, and handling data. Understanding what cryptographic primitives can do, and how they can be made together, is important to construct secure frameworks, however not enough. A few extra contemplations go into the outline of secure frameworks, and they are secured in different Berkeley graduate courses on security [2].
Cryptography is about correspondence within the sight of an enemy. It includes numerous issues (encryption, verification, key appropriation to give some examples). The field of current cryptography gives a hypothetical establishment considering which we may comprehend what precisely these issues are, the manner by which to assess conventions that indicate to explain them, and how to construct conventions in whose security we can have. We present the essential issues by talking about the issue of encryption [5].
According to [6], Cryptography is the place security designing meets arithmetic. It gives us the apparatuses that underlie most advanced security conventions. It is presumably the key empowering innovation for securing appropriated frameworks, yet it is shockingly difficult to do right. "Conventions," cryptography has frequently been utilized to secure the wrong things or used to ensure them in the wrong way. We'll see bounty more cases when we begin looking in detail at genuine applications [7]. ISSN: 2252-8814  KED-AES algorithm: combined key encryption decryption and advance … (Edwin R. Arboleda)

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Cryptography is the exploration of writing in mystery code and is an antiquated craftsmanship; the initially reported utilization of cryptography in composing goes back to around 1900 B.C. at the point when an Egyptian copyist utilized non-standard symbolic representations as a part of an engraving [8]. A few specialists contend that cryptography showed up suddenly at some point in the wake of composing was developed, with applications running from strategic letters to war-time fight arranges. It is nothing unexpected, then, that new types of cryptography came not long after the broad improvement of PC correspondences [9]. In information and broadcast communications, cryptography is fundamental when imparting over any untrusted medium, which incorporates pretty much any system, especially the internet [8].
There are two basic types of encryption, symmetric algorithm and asymmetric algorithm. According to [10] symmetric algorithms also called "secret key" uses the same key for both encryption and decryption and asymmetric algorithms or "public key" uses different keys for encryption and decryption [11]. A symmetric cryptosystem (or private key cryptosystem) utilizes one and only key for both encryption and unscrambling of the information. The key utilized for encryption and unscrambling is called the private key and just individuals who are approved for the encryption/unscrambling would know it. In a symmetric cryptosystem, the encoded message is sent over without any open keys joined to it while asymmetric or the public key there are two distinctive keys utilized for the encryption and decoding of information [8]. The key utilized for encryption is kept open thus as called open key, and the unscrambling key is kept mystery and called private key. The keys are created in a manner that it is difficult to get the private key from people in general key. The transmitter and the beneficiary both have two keys in an Asymmetric framework. Be that as it may, the private key is kept private and not sent over with the message to the beneficiary, in spite of the fact that the general population key is this is further explained by [11].
The advantages and disadvantages of symmetric and asymmetric cryptosystem was stated by [12], A symmetric cryptosystem is speedier, encoded information be exchanged on the connection regardless of the possibility that there is a probability that the information will be caught. Since there is no key transmitted with the information, the odds of information being decoded are invalid, it utilizes secret word validation to demonstrate the beneficiary's character and a framework just which has key can unscramble a message are the benefits of symmetric cryptosystem while in Asymmetric cryptosystem [13], cryptography there is no requirement for trading keys, along these lines wiping out the key conveyance issue [14], the essential preferred standpoint of open key cryptography is expanded security: the private keys absolutely never should be transmitted or uncovered to anybody, and in conclusion it can give advanced marks that can be denied [15]. The disadvantages of symmetric cryptosystem have an issue of key transportation. The private key is to be transmitted to the getting framework before the real message is to be transmitted [16,17]. Each method for electronic correspondence channels. In this way, the main secure method for trading keys would trade them by and by and can't give advanced mark that can't be revoked. While in asymmetric cryptosystem an impediment of utilizing open key cryptography for encryption is speed: there are well known mystery key encryption techniques which are altogether speedier than any right now accessible open key encryption strategy [18].
This standard indicates the Rijndael calculation [19,20], a symmetric square figure that can prepare information squares of 128 bits, utilizing figure keys with lengths of 128, 192, and 256 bits [21]. Rijndael was intended to handle extra piece sizes and key lengths, nonetheless they are not embraced in this standard. All through the rest of this standard, the calculation determined thus will be alluded to as "the AES algorithm." The algorithm might be utilized with the three different key lengths, mention above, and in this way, these different "flavors" might be alluded to as "AES-128", "AES-192", and"AES-256 [4]".
Warjri [22] proposed a new symmetric key algorithm called as KED (Key Encryption Decryption) and a new key generation method. Using modulo 69 and inverse modulo69, the proposed algorithm was used for encryption and decryption process, in which the same key is used both for encryption and decryption.

RESEARCH METHOD
The authors proposed a hybrid of KED that uses modulo 69, CHAOS-based cryptosystem, and AES algorithm. The key generation used in this hybrid uses that of KED and all the algorithm are used in encryption and decryption process [18]. The s-box and inverse s-box tables will be used in encryption and decryption respectively; they will be part of the process itself and not in the sent message. The Encryption process is shown in Figure 1 and The Decryption process is shown in Figure 2. Key generation algorithm KED Key Generation: a. Generating 'k2', firstly user enters a key. The length of the key is stored in 'kl'. Hence k2 is generated as follows: b. Where, 'i' is the position of each character in the key. 'kl' is the length of the key. 'val' is the integer value that has been assign to each character as shown in Figure 3. c. For 'k1', select any natural number say 'k1' where k1≠0 and must be relatively prime to 'm' (i.e., 'k1' should not have factors in common with 'm'). d. Find inverse modulo69 of 'k1' and store it in 'n1' Chaos Key Generation: a. Convert k1 and k2 to its 8-bit binary equivalent. b. Get the gray code of the binary form of k1 and k2, denote as J1 and J2.
Encryption KED: Figure 3. Synthetic values of alphabets [23] Int. J. of Adv. in Appl.  Figure 4, denoted as W1. c. The first digit will be the row x, and second digit will be the column y. d. Convert to binary the row x and column y. e. Convert to decimal the 8-bit binary for the cipher text. Decryption AES: a. Convert to binary to hexadecimal. b. Apply the inverse S-box as shown in Figure 5, denoted as W2. c. Covert to binary. c. Convert the 8-bit binary to its decimal equivalent, denoted as mi. KED: a. Assign integer value for cipher text as given in Figure 3. b. Subtract 'k2' from above integer value. c. Multiply above result with inverse modulo69 of 'k1' i.e., 'n1'. d. Finally calculate with modulo69.