COMPARATIVE STUDY OF ELGAMAL AND LUC ALGORITHM IN CRYPTOGRAPHIC KEY GENERATION

In today’s era of digital, data security in communication channel becomes important factor to be considered during exchange of information. Cryptography is one of techniques to send and receive information securely through an insecure channel. Based on the number of keys used, encryption methods are categorized as symmetric and asymmetric cryptography. Compared to symmetric cryptography that often suffers from key management issues, asymmetric cryptography delivers higher level of data security. Thus, asymmetric cryptography is more preferred when security if the priority. To determine suitable algorithm, three essential aspects should be considered: security, speed, and prime numbers. This study aims to compare the application of asymmetric cryptographic algorithms between ElGamal and LUC algorithms in the key generation process. A comparative analysis of these two algorithms was conducted by evaluating the processing speed and prime numbers during key generation process to determine the advantages and drawbacks from ElGamal and LUC algorithms. The application in this study was developed using PHP programming language by following the Waterfall Model. Application testing involved two kinds of tests: (i) Black Box test and (ii) System Usability Scale (SUS) test. Results show the application developed from this study successfully performed the encryption, decryption, and checking of prime numbers from ElGamal and LUC algorithms. It displayed ciphertext, plaintext, and the speed of the encryption and decryption process from both methods. The black box test showed that all application functions follow the user's needs, while System Usability Scale (SUS) test obtained an average score of SUS interpretation of 83.75. This value means the adjective ratings was “excellent”, the grade scale was “B”, and the acceptability range was “acceptable”. It is concluded that the LUC algorithm superior to ElGamal in terms of the speed of encryption process. However, during the decryption process the LUC algorithm responded slower than ElGamal.