A NOVELTY METHODS OF CRYPTOGRAPHY ALGORITHMS INTO LAYERED CIPHER ENCRYPTION AND DECRYPTION Antoni Faculty Of Engineering, Universitas Islam Sumatera Utara [email protected] Solly Aryza Faculty Of Science & Technology, Universitas Panca Budi [email protected] Bonar Harahap Faculty Of Engineering, Universitas Islam Sumatera Utara [email protected] Mahrani Arfah Faculty Of Engineering, Universitas Islam Sumatera Utara [email protected] Azmi Rizki Lubis Faculty Of Engineering, Universitas Islam Sumatera Utara [email protected] ABSTRACT Encryption is one method used to protect or maintain the data. Data that has encrypted will be kept confidential where the contents of the data are altered, so it does not correspond to the actual data. To be able to read data that has been encrypted earlier required a process called decryption. In the science of cryptography, the data will be safeguarded consists of three main components, that is the message that will be read (plaintext), the keys to perform cryptographic techniques (Key), and a random signal that is unreadable (ciphertext). Testing is done by sending the data in the form of words or sentences by using a secret key. Results of analysis of data from tests performed show that with the incorporation of some algorithm plated confidentiality of information can be safer because it takes several different stages to solve. KeywordS : Algorithm,Cryptography,Decryption, Encryption 1. Overview Cryptography is a science which studies how to keep data or messages remain By rapid growth of communication world, secure when transmitted from the transmitter especially in the field of information such as to the receiver without interference from third data, images, audio or video, we need a parties. According to Bruce Scheiner in his system that can maintain the confidentiality book "Applied Cryptography," cryptography is of such information. Security is a standard the science and art of keeping distributing requirement and becomes essential, the messages to stay safe or secure. secrecy of data requires a security Besides these terms, there is also another mechanism that can deal with the meaning that cryptography is the study of confidentiality of such information ( Solly mathematical techniques that relate to Aryza et al., 2018). aspects of information security such as data Encryption is the process of scrambling confidentiality, data validity, data integrity, method or means of securing the information and authentication of data. (Ikhwan & Rahim, to make such information can not be read 2016) The beginning of cryptography is without any specialized knowledge. understood as the science of hiding Encryption can be used for security purposes, but other techniques are still messages (Aspan & Aryza, 2018), but over needed to make communications secure, the times until today, the notion of mainly to ensure the integrity and cryptography evolved into a science of authentication of a message. This study was mathematical techniques used to solve conducted to analyze a method of security issues such as privacy and encryption-decryption so that it becomes a authentication (Indar Sugiarto, Thiang multi-layered password that aims to improve Thiang, & Timothy Joy Siswanto, 2008). the security of information (Aryza et al., There is four fundamental purpose of the 2018) . science of cryptography is that also the security aspect of information, namely: 2. Cryptography • Confidentiality is a service which is used to keep the contents of the data of anyone 3. Introduction to Cryptography Type but who has the authority or the secret key to 3.1 Types of Cryptography According to its unlock the information that has been Development encoded. Cryptographic algorithms can be classified into two types based on its development, namely the classical • Data integrity is associated with cryptography and modern cryptography. preservation of unauthorized data changes. To maintain data integrity system should Classical Cryptographic Algorithm have the ability to detect data manipulation This algorithm is used since before the era of by those who are not entitled to insertion, computerization and mostly uses a symmetric key deletion, and other data entry into the actual technique. The method to hide the message is to use data. the technique of substitution or transposition or both [4]. Substitution technique is to replace the • Authentication is associated with the characters in plaintext into other characters that the identification or recognition, either as a whole result is ciphertext. While transposition is the of systems or the information itself. Two technique of changing plaintext into ciphertext by parties communicating must be introduced means of permutations of character. It is a complex themselves. Information sent through the combination of both is underlying the formation of a canal must be authenticated authenticity of wide range of modern cryptographic the contents of the data, delivery time, and algorithms(Hesari & Sistani, 2017). others. Modern Cryptographic Algorithms • Non-repudiation or non-denial is an This algorithm has a more complex difficulty level attempt to prevent the denial of the delivery [2], and the strength is in key [5]. This algorithm or the creation of information by the parties uses a binary symbol because it follows the digital that send or make such information. computer processing operations. Thus requiring a basic form of knowledge of mathematics to master it [4]. 2.1 Main process in Cryptography 3.2 Types of Cryptography According to The Key Encryption is the process by which Cryptographic algorithms can be classified into two information or data before it is transmitted, it types based on the key, the symmetric algorithms is converted into a form that can hardly be and asymmetric algorithms [2]. recognizable as information initially using a specific algorithm. 3.2.1 Symmetric Algorithms A description is the opposite of encryption These algorithms are called symmetric because it that reshapes disguised as the initial has the same key in the encryption and decryption information.. process so this algorithm also often called single-key algorithm or one-key algorithms. Key in this algorithm is confidential or private so that the algorithm is also called the secret key algorithm [2]. Picture 2.Symmetric Algorithms Illustration Picture 1.Basic Cryptography Illustration Excess Symmetric Algorithms 2.2 The Term in Cryptography Here are the terms used in cryptography: Speed of operation is higher when compared to the asymmetric algorithm, because the speed is high Plaintext (M) is a message to be sent enough, it can be used in real-time systems. (containing the original data). Ciphertext (C) is an encrypted message Symmetric Algorithms Weakness (encrypted) which is the result of the encryption. For each delivery of messages with different user Encryption (Function E) is the process of needs different keys as well, so there will be converting plaintext into ciphertext. difficulties in the key management, commonly called Decryption (Function D) is the process of key distribution problem. conversion of ciphertext into plaintext, so that it becomes the initial data or original data. 3.2.2 Asymmetric Algorithms Key is a secret number, which is used in the This algorithm is called asymmetric because the key encryption and Decryption process. used for encryption is different from the key used for decryption. The key used for encryption is public key so that the algorithm is also called a public key algorithm. Whereas the key for decryption using a secret key or private key [2]. Picture 3.Asymmetric Algorithm Illustration Pictur Asymmetric Algorithm advantages: e.5 Alphabetical Order Index Security issues at key distribution can be better. Key management problems better because fewer Alphabet used to build the message (plaintext) was number of keys. given an index number as shown above. The characters are used as keys were also taken from the Weakness Asymmetric Algorithm: alphabet. The key will be "added" or create a "shift" The speed is lower when compared to a character of the original message to establish a symmetric algorithm. password. If when added or shifted generate an For the same level of security, the key used is index of more than 25, the order of the index will longer than the symmetric algorithm. return to 0, From Z back to A. 4. Testing Methods 4.1.2 Atbash Cipher At the beginning the data security with cryptography Another classic example is the Atbash Cipher. This that uses the classic cryptographic algorithms are still Atbash Cipher permute letters from front to back so character-based, using a pen and paper only, no back to front as shown below: computer. Classical cryptographic algorithm belongs to the symmetric key cryptography. Classic cryptographic algorithms : Pesan: ABCDEFGHIJKLMNOPQRSTUVWXYZ Substitution Ciphers Sandi: ZYXWVUTSRQPONMLKJIHGFEDCBA Transposition Ciphers In this study the author will only discuss about Substitution Ciphers. By using a password Atbash, ZENIUS message will 4.1 Substitution Ciphers be AVMRFH password. The recipient only needs to Substitution cipher change one letter or character in swap the order of the letter behind it. Atbash name is the message (plaintext), according to the rules of the derived from its first use in Hebrew letters, the Aleph- key (key), it becomes another character in the secret Tav-Shin-Beth, the first, last, second and penultimate password (ciphertext). Here is part of