A New Hybrid Diffie-Hellman and Caesar Cipher Algorithm for Cryptography

Caesar cipher algorithm is one of the ancient algorithms. However, due to advances in technology the algorithm is now much simple to breach. This is because; each letter in the message is replaced by the same letter as specified. To raise the safety, some changes can be made. So, here we are going to use another arithmetic algorithm Diffie - Hellman's mode of changing the key to find the secret key and use simple calculations to verify data encryption. After obtaining a private shared key using the Diffie-Hellman method, depending on the operating mode with 26 keys to get the value of 26 or less, then the current character is taken with the key when the additional value of the new character. In any letter in the position of an 'x', the key first increases with an 'x' and is adjusted to get the encrypted letter. Therefore, 2 messages are repeated 2 times and the third letter has 3. This increases safety. This technology can be used to securely transfer sensitive information from one person to another.


Introduction
Data safety is important aspects of human life.No one can communicate safely.Leak information is always possible.This helps make data safer.There are two types of cryptographic methods: symmetric and public.Symmetric is a method of applying the same key.Public key cryptography is a method in which only one key is used in the encryption process and another special key is used in the encryption process.As with both encryptions only one key is used for the decryption purpose.However, since such cryptography is the most important feature of science, it is not important to the outside world at any cost.For example, a shift of 2 means A, which is then replaced by C, B and B. The sender can encrypt the data using this key and the recipient can decrypt it by using the same key.The below is made using 5 keys.

Plain text
Cipher text I love my life.

N qtaj rd qnkj
As you can see from above example, the plain text is simply shifted by 5 alphabets.In order to decrypt the above cipher text we simply should shift 5 alphabets backward.

Literature Survey
This paper expands the domestic table with numerical knowledge, so this number system can be used.It combines Vigenere's coding and modified Caesar cipher technique to retrieve cipher text from a given plain text and key [1].
Encryption is the conversion of plain text or plain text into hidden text (cipher text), usually the Beributuk code [2].Encryption of text data Step and result with this method WAKE encrypts back in Caesar cipher technology, thus protecting encrypted data [4].
This encryption technology adopts a combination of Caesar cipher and XOR encryption and is programmed using C ++ [6].
Subsequently, some possible scenarios were tested to verify the strength of the security program, suggesting an improvement in the security of the data transmission over the wireless medium without affecting the processing time [7].

III. Problem Definition
Now-a-days there is issues in cyber security where there are number of data breaches taking place, this can be overcome by our process in which we use hybrid of Caesar Cipher and Diffie-Hellman algorithm.
To streamline this process, we aim to develop an algorithm that can simulate this workflow by allowing the motivation that systems use mathematical operations that are hard to reverse This algorithm allows the process to be completed in less time compared to AES and DES algorithms and more secure than existing Caesar Cipher.

IV. Proposed Algorithm
In the first part of the proposed algorithm a public key exchange takes place between the two users.This exchange is slightly different Diffie-Hellman method.The algorithm is shown below.To make a Diffie-Hellman, the last two users are Jame and Robert, they communicate in the same channel, knowing that they are private, receiving whole numbers corresponding to P and Q, i.e.P is the first number and Q is producers of p. Generator q is a multiplied number of whole numbers less than p, which does not give the same result of two whole numbers.The value of P can be but the value of q is small B. Algorithm 2: Caesar Cipher

Results and Discussion
In order to find out how efficient the proposed algorithm is?Let us take the example of two of the most secure cryptographic algorithms in use which are AES and DES algorithms.As you can see our proposed algorithms takes far less time compared to those secure algorithms.As security is not the only criteria an algorithm can be assessed, the proposed algorithm might not be more secure than AES and DES algorithms, but it certainly is faster than those two algorithms.
We are generating a private key using two public keys from two users, then that generated private key is used for encryption or decryption technique, It is shown in below figure .4Available online at: https://jazindia.com-982 -From Fig. 5, the entered text "I love my life" is converted in to encrypted cipher text as "n qtaj rd qnkj" with a key value of 5, we can get back our original text by decryption From Fig. 6, the entered text "Ocean is blue" is converted in to encrypted cipher text as "thjfs nx gqzj" with a key value of 5, we can get back our original text by decryption

Conclusion
This algorithm is considered effective if there are sufficient guarantees to protect certain data.When there is no difference in security, execution time is important because it should not take much time to execute a particular algorithm.The given algorithm delivers results much faster than modern cryptographic methods such as AES, DES and DFS algorithms, which are widely used in NASA, FBI and ISRO.Characters such as spaces are also hidden.

A. Algorithm 1 :
Diffie-Hellman Step1: Start Step2: Select two different independent keys A and B Step3: Now select the shared private key A and B Step4: Now send a duplicate secret key shared from A to B and vice versa from B to A Step5: Multiply the value obtained by the secret key to get the key called the shared crypto key, let this number be called 'x' Step6: Stop

AFig 2 :
Fig 2: Encryption and Decryption of Caesar Cipher techniqueIn order to encrypt a given text, we must provide the full value as input, which shifts those multiple numbers of positions.So this encryption can now be represented by a modular arithmetic by first converting the letters into numbers in order.

Fig 6 :
Fig 6: Execution of Caesar Cipher algorithm as mentioned in table 2

Table 2 :
Decryption Diffie-Hellman is а method of сreаting shared privacy between the two persons , thus the secret саnnоt be seen .This is very useful beсаuse yоu саn use this methоd to сreаte аn enсryрtiоn key with someone else, and then start encrypting your traffic with the same key.Even if the traffic is reсоrded and аnаlyzed later, there is no way tо know what the key is, even if the exchanges that do it аррeаr.It is not аsymmetriс сryрtоgrарhy.

Table 3 :
For Encryption

Table 4 :
For DecryptionFrom the table III, the time taken for the execution of file by encryption technique for AES, DES, and Proposed algorithm is 1.794seconds, 2.165 seconds, 0.501 seconds respectively From the table IV, the time taken for the execution of file by decryption technique for AES, DES, and Proposed algorithm is 1.998 seconds, 2.215 seconds, 0.564 seconds respectively It abbreviates Caesar cipher algorithm, which ensures quick encryption and provides additional security.Abbas, H. Mostafa and A. N. Mohieldin, "Low Area and Low Power Implementation for CAESAR Authenticated Ciphers," 2018 New Generation of CAS (NGCAS), 2018, pp.49-52, doi: 10.1109/NGCAS.2018.8572255.