Implementation of Trifid Cipher Algorithm in Securing Data 1 st Rita Novita Sari, 2 nd Ratna Sri Hayati, 3 th Hardianto, 4 th Asbon Hendra Azhar, 5 th Lahmudin Sipahutar, 6 th Ivi Lazuly Faculty of Engineering and Computer Science Potensi Utama University Medan, Indonesia rita.ns89@gmail.com, ratnayach@gmail.com, hardiantoandre08@gmail.com, asbon.upu@gmail.com, mudinsipa@gmail.com, ivylazuli@gmail.com Abstract-- In the digital era, data transmission is mostly done by using internet media such as sending via email and social media. In sending information using the internet there are many threats that can occur such as corruption, tapping, modification, and fabrication. In securing information there are several ways including using data disguise techniques called cryptography. The Trifid Cipher algorithm uses polybial cubes to convert letters to numbers and write numbers vertically under the message with sequences, columns, and rows. Then the numbers are read horizontally and then grouped into 3 parts then the cube is used again to convert numbers to ciphertexts. Keyword: Cryptography, Tirfid Cipher, Securing Data I. INTRODUCTION In the digital era, data transmission is mostly done by using internet media such as sending via email and social media. In sending information using the internet there are many threats that can occur such as corruption, tapping, modification, and fabrication. For that, we need security, so that the information we send cannot be accessed by people who do not have permission so that the confidentiality of information can be maintained. In securing information there are several ways including using data disguise techniques called cryptography and message hiding techniques called steganography. Cryptography is the science of protecting the sender of a message by converting it into certain codes and is only intended for people who only have a key to change the code again which functions in maintaining the confidentiality of data or messages. Cryptography has two important concepts, namely encryption and decryption. Encryption converts information or data into a form that is almost unrecognizable, such as initial information using a particular algorithm, while decryption changes the disguised form into initial information. One method that can be done is the Trifid Cipher algorithm. Trifid Cipher algorithm is a classic cryptographic algorithm. Where this algorithm was discovered by Felix Delastele. This algorithm uses a square and character solving to obtain the diffusion effect on the ciphertext. Trifid Cipher algorithm is an algorithm that is difficult to solve, for example, step (1) uses a cube to convert letters to numbers and write numbers vertically below the message in order of layers, columns, and rows, (2) numbers are read horizontally and grouped into triplets, (3) the cube is used again to change the number to the letter that gives us the ciphertext. To decipher encrypted messages, first convert each letter to the appropriate number through the cube, then divide the long string of numbers into the same three lines, read each column and use the cube to convert three numbers to plaintext letters. In this study, the author will Trifid Cipher algorithm to secure data. II. RELATED WORKS The research conducted by Esrawati Simbolon, Garuda Ginting and Kurnia Ulfa (2018) discusses designing a text file encryption application using the Trifid Cipher algorithm. In this algorithm, using square cubes and character solving to obtain diffusion effects on the ciphertext. Using the cube to change letters to numbers and write numbers vertically below the message in layers, columns, and rows. Numbers are read horizontally and grouped into triplets, then the cube is used again to change the number to the letter that gives us the ciphertext. [1] Research conducted by Dian Novinto and Yohanes Setiawan (2018) designed information security applications using the Least Significant Bit (LSB) Method and the Advanced Encryption Standard (AES) Cryptography. In this study the data is encrypted using AES cryptography then the data is inserted into the image without significantly reducing image quality so that it cannot be distinguished from images that have been inserted data. [2] The research conducted by Angga Aditya Permana (2018) applies Vigenere Cipher cryptography on text messages based on Android. This study aims to build text message cryptography applications on android-based smartphones with the Vigenere Cipher method. This method encrypts the text of the message into a secret message which then results are forwarded as text messages to the message sending application such as the SMS (Short Message Service) application, Whatsapp, Line, and the like to be decrypted. This study produces an android-based application that can send encrypted message text using the Vigenere Cipher method to provide more security in the process of information exchange. [3] Research conducted by Azlin and Fitriah Musadat (2018) applied the Base64 algorithm to secure data. In this study the base64 algorithm is able to secure text data by encrypting text files into a random character and returning data text by describing the results of encryption into the