Implementasi Fungsi Hash MD5 dan Kriptografi Algoritma RSA pada Pembuatan Tanda Tangan Digital

Pada penelitian ini dibahas penerapan tanda tangan digital sebagai bentuk penjagaan keontentikan suatu dokumen elektronik yang dibuat dengan menggabungkan dua algoritma, yaitu fungsi hash MD5 (Message Digest 5) dan RSA (Rivest Shamir Adleman). Isi dokumen elektronik diberikan fungsi hash MD5 sehingga menghasilkan message digest. Selanjutnya message digest akan dienkripsikan menggunakan algoritma kriptografi RSA sehingga menghasilkan tanda tangan digital. Hasil pengujian menunjukkan bahwa tanda tangan digital yang dihasilkan adalah berbeda-beda dari setiap dokumen elektronik. Dokumen elektronik yang menghasilkan nilai dekripsi tanda tangan digital dan message digest modulo yang sama menunjukkan bahwa dokumen elektronik tidak mengalami perubahan pada isinya. Sebaliknya, dokumen elektronik yang tidak menghasilkan nilai dekripsi dan tanda tangan digital dan message digest modulo yang sama menunjukkan bahwa dokumen elektronik telah mengalami perubahan pada isinya.

A Hash-Based Quantum-Resistant Chameleon Signature Scheme

As a standard digital signature may be verified by anybody, it is unsuitable for personal or economically sensitive applications. The chameleon signature system was presented by Krawczyk and Rabin as a solution to this problem. It is based on a hash then sign model. The chameleon hash function enables the trapdoor information holder to compute a message digest collision. The holder of a chameleon signature is the recipient of a chameleon signature. He could compute collision on the hash value using the trapdoor information. This keeps the recipient from disclosing his conviction to a third party and ensures the privacy of the signature. The majority of the extant chameleon signature methods are built on the computationally infeasible number theory problems, like integer factorization and discrete log. Unfortunately, the construction of quantum computers would be rendered insecure to those schemes. This creates a solid requirement for construct chameleon signatures for the quantum world. Hence, this paper proposes a novel quantum secure chameleon signature scheme based on hash functions. As a hash-based cryptosystem is an essential candidate of a post-quantum cryptosystem, the proposed hash-based chameleon signature scheme would be a promising alternative to the number of theoretic-based methods. Furthermore, the proposed method is key exposure-free and satisfies the security requirements such as semantic security, non-transferability, and unforgeability.

Implementasi Sistem Otentikasi Dokumen Berbasis Quick Response (QR) Code dan Digital Signature

The authenticity and integrity of documents are essential in data exchange and communication. Digital documents must be verifiable for their authenticity and integrity by all parties that use the documents. Generally, digital documents can be authenticated by using digital signatures. This study aims to implement a document authentication system based on Quick Response (QR) code and digital signature. As the case study, the document authentication system is implemented to generate digital signatures for student’s certificate documents. Furthermore, the system can also verify the authenticity of the certificate documents. Creating a digital signature requires a hash function algorithm for generating the message digest of the document. In addition, an algorithm to generate the public key and the private key used in the encryption/decryption of the message digest is also needed. The hash function utilized in this study is the Secure Hash Algorithm-256 (SHA-256), while the algorithm used for encryption/decryption is the Rivest-Shamir-Adleman (RSA) algorithm. The system is evaluated by verifying 30 student certificate documents, of which 15 of them were certificates with QR code signature generated by the system and the other 15 were certificates with QR code signature generated using a random QR code generator. The system’s testing results demonstrate that the system can ensure the authenticity and integrity of the signed certificate documents to prevent document falsification. All documents that contain random QR codes were correctly identified as false documents.

Survey on Approaches to Detect Sinkhole Attacks in Wireless Sensor Networks

Due to the wide range of applications in public and military domains, wireless sensor network (WSN) is evolving as a popular technology. This WSN consists of a large number of sensors that are spread across a geographical area thatare self-configuring in nature. These nodes are of low cost and resource-constrained nodes. Because these reasons the network becomes vulnerable to many network attacks. There are many types of attacks among which one of the serious attacks is the sinkhole attack, which is one of the destructive routing attacks. It causes the adversary node to attract all or most of the traffic from the neighbors by broadcasting false routing updates of having the shortest path to the central station. This paper is a survey on various methods implemented to overcome sinkhole attacks like Hop Count Monitoring scheme, Key Management Approach, Message-Digest Algorithm.

Performance Analysis of Cryptographic Hash Functions Suitable for Use in Blockchain

A blockchain, or in other words a chain of transaction blocks, is a distributed database that maintains an ordered chain of blocks that reliably connect the information contained in them. Copies of chain blocks are usually stored on multiple computers and synchronized in accordance with the rules of building a chain of blocks, which provides secure and change-resistant storage of information. To build linked lists of blocks hashing is used. Hashing is a special cryptographic primitive that provides one-way, resistance to collisions and search for prototypes computation of hash value (hash or message digest). In this paper a comparative analysis of the performance of hashing algorithms that can be used in modern decentralized blockchain networks are conducted. Specifically, the hash performance on different desktop systems, the number of cycles per byte (Cycles/byte), the amount of hashed message per second (MB/s) and the hash rate (KHash/s) are investigated. The comparative analysis of different hashing algorithms allows us to choose the most suitable candidates for building decentralized systems type of blockchain.

Implementasi Quick Response (QR) Code Pada Transaksi Pembayaran Dengan Enkripsi Message-Digest Algortihm 5

The rapid development of the times has made the community busy with various activities that collide with the limited time they have. This causes people to always look for ways to be able to carry out all the demands of these activities effectively and efficiently. Technological innovations such as electronic payment systems and virtual queues are one of the answers that can be used to help people carry out activities. The existence of this electronic payment system makes it easier for people to make payment transactions with this virtual queue which is a solution to solving queuing problems which usually take a long time, so that this virtual queue can help people to cut the time that is usually used to queue and allocate it for activities other.

Jpeg/Exif Message Digest Compilation With SHA512 Hash Function

Security information method for jpeg / exif documents generally aims to prevent security attack by protecting documents with password and watermark. Both methods cannot used to determine the condition of data integrity at the detection stage of the information security cycle. Message Digest is the essence of a file that used to represent data integrity. This study aims to compile a message digest to detect changes that occur in jpeg / exif documents in information security. The research phase consists of five stages. The first stage, identification of the jpeg / exif document structure conducted using Boyer-Moore string matching algorithm to find jpeg/exif segments location. The Second stage is segment content acquisition, conducted based on segment location and length obtained. The Third step, computing message digest for each segment using SHA512 hash function. Fourth stage, jpeg / exif document modification experiments to identified affected segments. The Fifth stage is selecting and combining the hash value of the segment into message digest. Obtained result show message digest for jpeg / exif documents composed of two parts, the hash value of the SOI segment and the APP1 segment. The SOI segment value used to detect modifications for jpeg to png conversion and image editing. The APP1 hash value used to detect metadata editing. The SOF0 hash values use to detect modification for image recoloring, cropping and resizing.

CLIFD: A novel image forgery detection technique using digital signatures

The paper presents a new image forgery detection technique. The proposed technique uses digital signatures; it generates a digital signature for each column and embeds the signature in the least significant bits of each corresponding column’s selected pixels. The message digest algorithm 5 (MD5) is used for digital signature generation, and the fourleast-significant-bit substitution mechanism is used to embed the signature in the designated pixels. The embedding of the digital signature in the selected pixel remains completely innocent and undetectable for the human visual system. The proposed forgery detection technique has demonstrated significant results against different types of forgeries introduced to digital images and successfully detected and pointed out the forged columns.