Hybrid Cryptosystem dengan Algoritma Cramer-Shoup dan Spritz untuk Pengamanan Dokumen Digital

Abstract

Symmetric algorithms are known for their speed but face significant challenges in secure key distribution, as the same key must be shared between sender and receiver, which makes it vulnerable to interception. In contrast, asymmetric algorithms provide enhanced security but are less efficient when encrypting and decrypting large text messages. This research aims to enhance the security of digital data and documents through the implementation of a hybrid cryptosystem that integrates the Cramer-Shoup and Spritz algorithms. Brute force testing is conducted to evaluate the system's resilience against brute force attacks, along with an analysis of the system's effectiveness, encryption-decryption speed, and efficiency in protecting various types of data and digital documents (such as .docx and .pdf files). The research methodology includes a literature review, analysis of the encryption-decryption process, brute force testing to assess system strength, and performance testing using Python. Speed test results indicate that the hybrid cryptosystem achieves fast encryption-decryption times, with an encryption time of 0.002607 milliseconds and decryption time of 0.001537 milliseconds for 400 characters. For digital documents in .pdf format, encryption time is 0.424478 milliseconds, and decryption time is 0.404343 milliseconds. Furthermore, brute force testing confirms the system's resistance to brute force attacks, attributed to the combination of Cramer-Shoup and Spritz algorithms, which increase the complexity of cracking the encryption key. The application of the SHA-3 hash function also proves effective in maintaining data integrity. In conclusion, the hybrid cryptosystem offers a secure and efficient solution for protecting various types of digital data, including text and documents, while also demonstrating resilience to brute force attacks.