Signcryption Algoritma RSA Signature dan Rabin-P pada Pesan Digital Portable Document Format (PDF)

Abstract

The importance of securing digital communication has grown significantly in line with the rapid evolution of communication technologies and their integration into daily activities. This research presents the design and development of a secure system for handling digital PDF documents through a signcryption approach that merges encryption and digital signing into a unified process, aiming to ensure confidentiality, data integrity, authentication, and non-repudiation. The RSA algorithm is applied for signing and verification, while Rabin-p is used for encryption and decryption, with SHA-256 generating the message digest. Implementation is carried out using Python and the Streamlit framework, followed by comprehensive performance and complexity evaluations on documents of various sizes. Experimental results indicate that signcryption takes an average of 21.761 ms for a 20,000 KB file, while unsigncryption, particularly Rabin-p decryption, can take up to 534.089 ms, making it the most time-intensive. Despite increasing message sizes, RSA verification remains efficient, with all major operations showing linear time complexity Θ(n). The system meets NIST’s baseline security standards and demonstrates strong potential as an effective and practical solution for securing digital messages.Digital message security has become a crucial factor with the rapid development of communication technology and its integration into everyday life. This research aims to develop and implement a security system for digital documents in Portable Document Format (PDF) using a signcryption technique that combines encryption and digital signature processes in a single step to ensure confidentiality, integrity, authentication, and non-repudiation. The RSA Signature algorithm is used for signing and verification, while Rabin-p is applied for message encryption and decryption. SHA-256 is used as the hashing function to generate the message digest. The system is implemented using the Python programming language and the Streamlit framework , followed by performance and complexity testing on documents of various sizes. Experimental results show that the average time for signcryption is 21.761 ms for a 20,000 KB file, while unsigncryption reaches 534.089 ms, with Rabin-p decryption being the most time-consuming. RSA signing time increases with message size, but verification remains efficient. All main processes demonstrate linear time complexity Θ(n), while theoretically, RSA has Θ(n²) and Rabin-p has Θ(n). The system complies with NIST's minimum security standards and is expected to provide an effective solution for securing digital messages