ORCID Profile
0000-0002-7716-2206
Current Organisations
Institut Teknologi Bandung
,
Universitas Sumatera Utara
,
University of Technology Sydney
,
University of New South Wales
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: IOP Publishing
Date: 03-2018
Publisher: IOP Publishing
Date: 05-2020
DOI: 10.1088/1757-899X/851/1/012069
Abstract: Image is a visual representation of an object The process of sending information, especially images, can be done anywhere and with any intermediary, but not all information is public. Sometimes someone needs privacy or security from data or information that will be sent or received. One way to secure image files is to use cryptography. Cryptography is the study of how to keep data or messages safe when sent, from the sender to the recipient, without experiencing interference from third parties. In this study cryptography used is Rail Fence Cipher that was combined with steganography, so that the secret message could not be seen in plain view. Steganography serves to hide secret messages in other messages, so the secret is a very hidden existence. There are several methods in Steganography, one of which is Least Significant Bit. The concept of Least Significant Bit works by replacing the last bit of RGB image, where the message is converted first into bits. Based on experiments conducted on the Rail Fence Cipher algorithm, the time of encryption and decryption needed when the resolution of the image gets larger is linearly proportional to the value. The image does not show significant changes before and after inserting a secret message.
Publisher: IOP Publishing
Date: 03-2018
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012037
Abstract: Cryptography is a study of mathematical techniques to secure messages by encoding the messages so it cannot be read by a third party. There are two types of algorithms in cryptography, symmetric algorithm and asymmetric algorithm. Asymmetric algorithms, such as Rabin-p cryptosystem, are known to be secure if the key sizes are long enough. However, asymmetric algorithms are ineffective to encrypt large data since the calculations consume CPU time and the resulting ciphertext is multiple times bigger than the original data. In this research, we combine Rabin-p cryptosystem and One Time Pad (OTP) in a hybrid scheme to solve this problem. The OTP is used to encrypt the data (images) and Rabin-p algorithm is used to encrypt the OTP key. In this research, we demonstrate how to secure a *.bmp file with this hybrid scheme.
Publisher: IEEE
Date: 11-11-2021
Publisher: IEEE
Date: 11-11-2021
Publisher: IEEE
Date: 11-11-2021
Publisher: IEEE
Date: 11-11-2021
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012008
Abstract: USU Repository is an institutional digital information system provided by Universitas Sumatera Utara (USU) that preserves and distributes academic papers, such as thesis and dissertation, from all departments in USU. A search box is provided to help search relevant topics from this repository. However, sometimes the search results returned were irrelevant and did not satisfy the user’s expectations. One of the causes for this situation is that the search engine could not perform optimally, particularly if the query were long and complicated. One approach that can be used to solve the problem is using semantic search. Semantic search is an information retrieval process from a sentence that involves understanding the results returned by natural language processing. In light of this approach, this paper aimed to propose a semantic search to seek the relevance between the user’s input query and academic papers returned as search results. This study implemented word2vec method in converting sentences into vectors. This study indicated average precision scores for small datasets as 46% and 73% for larger datasets.
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012028
Abstract: In Indonesia, especially in Medan, North Sumatra, Hokkien is used in everyday life within the Chinese community. However, learning the language is still done manually. Therefore, the authors intend to create an Android-based Hokkien dictionary application. The most common typing errors found were deleting and inserting single characters, substituting and reversing adjacent characters. Exact string matching can perform a quick search, but the search will fail when the incorrect input is entered. This study aims to prove the advantages and disadvantages of each algorithm in accessing information in addition to displaying the results of the running time of both algorithms. The results showed that the search time for the Burkhard-Keller Tree algorithm increased by 72% and 96% for the Not So Naive algorithm when searching on a database containing 200 words and 400 words. The Not So Naive algorithm has a mean running time of 26.9 ms and a mean running time of 53.5 ms on the Burkhard-Keller Tree algorithm.
Publisher: IOP Publishing
Date: 05-2020
DOI: 10.1088/1742-6596/1542/1/012039
Abstract: The Benaloh public key cryptosystem is an asymmetric cryptosystem with the property of homomorphic encryption scheme. This study explains how to use Benaloh public key cryptosystem to encrypt a simple text. To increase the clarity of the computation, some intermediate variables which are not available in the original Benaloh cryptosystem have been used. The Benaloh algorithm has been implemented in Python programming language version 2.7.15.
Publisher: IOP Publishing
Date: 06-2020
DOI: 10.1088/1742-6596/1566/1/012084
Abstract: Image is a form of visual data or information that is often used today. Sending data or information can be done in various ways and anyone. However, not all contents of existing information are public. It is not uncommon that information is misused by irresponsible parties. For this reason, security is needed for confidential information. This image security can be done with Steganography Technique. Steganography technique is a method for hiding information in an image. The method used is the LSB (Least Significant Bit) method. Where every bit lowest in the image media bytes will be replaced with the message bits that will be inserted. The bit used is the last bit of the RGB binary. The goal is that the message sent by the sender cannot be known by a third party, and can arrive safely to the recipient of the message. To make the confidentiality of messages more secure, it is necessary to hide the existence of messages to overcome the weaknesses of the LSB method used, so the authors combine them with the RSA RPrime algorithm (Rivest Shamir Adleman) for the encryption and decryption process. The security of the RSA RPrime algorithm lies in the level of difficulty in factoring non prime numbers into prime factors. The longer the key bits, the more difficult it is to solve because of the difficulty of factoring these two very large numbers. The results showed the test using a document file 2.93 MB with cover image size of 5760 x 3840 pixels, where in the larger the file inserted, then the time of encryption and decryption process is also long.
Publisher: IOP Publishing
Date: 03-2018
Publisher: IOP Publishing
Date: 06-2020
DOI: 10.1088/1742-6596/1566/1/012063
Abstract: The RSA public key cryptosystem was among the first algorithms to implement the Diffie-Hellman key exchange protocol. At the core of RSA’s security is the problem of factoring its modulus, a very large integer, into its prime factors. In this study, we show a step-by-step tutorial on how to factor the RSA modulus using Euler’s factorization algorithm, an algorithm that belongs to the class of exact algorithms. The Euler’s factorization algorithm is implemented in Python programming language. In this experiment, we also record the relation between the length of the RSA moduli and its factorization time. As a result, this study shows that the Euler’s factorization algorithm can be used to factor small modulus of RSA, the correlation between the factoring time and the size of RSA modulus is directly proportional, and better selection of some Euler’s parameters may lead to lower factoring time.
Publisher: Sciedu Press
Date: 11-07-2023
Abstract: The need for digital technology involvement in education is increasingly apparent, so learning techniques are required to be prepared in various digital formats. Using digital learning materials enables teachers to implement the current concept of literacy, i.e., multimodal literacy. This study aims to find out the students' need for digital literacy and their perceptions of using the Roblox game as the learning media to improve their multimodal literacy. This descriptive study used a survey method, taking the second-year junior high school students in the 2021-2022 academic year in one of the state junior high schools in Medan, Indonesia as the respondents. The data were collected using two sets of closed-ended questionnaires. The data obtained from the first questionnaire were analyzed using a forced choice technique for yes or no answers, while the data obtained from the second questionnaire were analyzed using a 4-Point Likert Scale. The results indicate the students' need for digital literacy and their good perceptions of using Roblox as the learning media in improving their English multimodal literacy. It is concluded that teaching English at junior high school is expected to be designed in a digital format by involving games as the media, facilitating the students to improve their English multimodal literacy.
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012040
Abstract: Exchanging digital messages by electronic means has a major security concern. The data being sent can be accessed and read by some unintended parties if there is no security system involved. Cryptography obscures the messages being sent and they can only be read by intended recipients by using the right key. Using asymetric cryptography algorithm such as Multi-Factor RSA may help to obscure a message with high security however, the ciphertext is usually much larger than the message so it takes much more time to transmit. In order to solve this problem, this research combines the Multi-Factor RSA with the Levenstein Code algorithm in a cryptocompression system to compress the size of the message being sent. This research also compares encrypt-then-compress scheme with compress-then-encrypt scheme. The result shows that encrypt-then-compress scheme has a better compression ratio than the compress-then-encrypt scheme. On the contrary, in terms of actual time performance, the compress-then-encrypt scheme is faster than encrypt-then-compress scheme.
Publisher: IOP Publishing
Date: 03-2018
Publisher: IOP Publishing
Date: 02-0001
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012047
Abstract: Pathfinding is the method for determining the shortest path. Pathfinding is widely used in various fields of Computer Science. One of them is game development. This research will design and analyze the pathfinding using the A-Star algorithm and implement it on a tree planting game. The Artificial Intelligence in the game will find its own shortest path from the start node to the goal node. The heuristic of A-Star is the Manhattan Distance that allows movement in four different directions. The result shows that the number of visited nodes will increase if the grid has many obstacle nodes, and the average time of the A-Star pathfinding process is 0.0732 seconds.
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012042
Abstract: One way to keep digital information secure is by using cryptographic techniques. With respect to its keys, cryptography generally is ided into two types: symmetric and asymmetric. Symmetric cryptography algorithm uses the same key in both encryption and decryption while asymmetric uses different keys for each of these processes. Asymmetric cryptography algorithm is known to be ineffective to encrypt big messages since it takes more CPU time to do the computation and the resulting ciphertext is usually much bigger than the original message. To eliminate these problems, in this research, we combine Rabin-p cryptosystem, an asymmetric cryptography algorithm, and affine cipher, a symmetric cryptography algorithm, in a hybrid scheme in order to secure messages from unwanted parties. The affine cipher is used for message encryption while Rabin-p is used for affine cipher’s key encryption. The result of this research is a hybrid cryptography scheme that can encrypt and decrypt message in the form of *.pdf files and be able to restore the message without losing integrity.
Publisher: IOP Publishing
Date: 06-2019
DOI: 10.1088/1742-6596/1235/1/012062
Abstract: Masjid has a function to do various activities, both worship activities to God and social activities to fellow human beings. In Masjid there is an instance that has the responsibility of determining the schedule of khatib, immam, and plans for various other activities. It is known as the masjid prosperity council or DKM. The DKM should be able to provide information to the pilgrims quickly. But in reality, people still have difficulty getting schedules and information about activities that will take place at the masjid. The length of scheduling that is done manually causes the discovery of activity schedule clashes, activities that are not in accordance with priorities, loss of previous plans, and khatib or immam who are unable to attend. To overcome this problem one approach is needed that can help the masjid prosperity council more easily manage schedules. In this study, Genetic Algorithm are used to solve this problem because of its good ability to be used in scheduling activities. After testing, the system built is able to provide solutions to problems in scheduling clashes of khatib and immam in the masjid.
Publisher: IOP Publishing
Date: 05-2020
DOI: 10.1088/1742-6596/1542/1/012024
Abstract: The Rivest-Shamir-Adleman (RSA) public key cryptosystem has been extensively used to secure digital communication since more than forty years. The security of RSA relies on the hardness of factoring a big integer into its two big prime factors: the bigger the integer, the securer the cryptosystem. However, the RSA cryptosystem is proven to be not semantically secure. Some variants of Dependent RSA encryption schemes have been introduced by Pointcheval to overcome this problem. This study shows how the first variant of Dependent RSA (DRSA-1) encryption scheme is used to secure text. All algorithms have been implemented in the Python programming language version 2.7.15.
Publisher: IOP Publishing
Date: 06-2021
DOI: 10.1088/1742-6596/1898/1/012039
Abstract: As with other form of digital media, image can also contain private information that should be kept secret. Commonly, symmetric and asymmetric cryptosystem can be used to secure an image. Symmetric-key cryptography is not a best solution as the secret key has to be transmitted through private channel. Asymmetric-key cryptosystem, however, allows transmission of key through public channel, but requires high computational power and long computational time. This paper proposes a neural cryptography approach to protect image by using tree parity machine and Vigenère cipher. By using this approach, the secret key will never be transmitted. Moreover, the whole process does not require high computational power and long computational time as in public-key cryptosystem. To overcome the weakness of Vigenère cipher, change is made to the algorithm by multiplying the key value with y-axis of image. The effectiveness is validated by the value of pearson correlation that is close to 0. Lastly, the result of experiments show neural synchronization time depends on the size of network, initial weights and randomly generated input vector.
Publisher: IOP Publishing
Date: 06-2020
DOI: 10.1088/1742-6596/1566/1/012071
Abstract: Confidentiality and size of data are some significant aspects in data exchange. Public key encryption algorithms, such as El-Gamal is known as to preserve confidentiality. On the other hand, public key encryption algorithms tend to increase the size of the encrypted data, making it difficult to transmit to the other party. This research will combine the ElGamal public key encryption algorithm with Even-Rodeh codes. ElGamal is used to secure data and Even-Rodeh codes are used to compress data. The parameters is being tested are the compression ratio and space savings. In this research, we will do an experiment that includes some data texts from Artificial Corpus. The results show that the crypto compression system can reduce the size of the transmitted data and the transmitted data could be revert back to the original data while still maintains its confidentiality.
Publisher: IOP Publishing
Date: 06-2020
DOI: 10.1088/1742-6596/1566/1/012073
Abstract: Data compression was born as a solution to human needs for digital data. This research compares two compression algorithms, namely the Start-Step-Stop code algorithm and Gopala-Hemachandra codes 2 (GH -2 (n)) algorithm in the case of text file compression. compression ratio (CR), space savings (SS), bit rate and running time are calculated in the test as consideration to compare the advantages of both algorithms. Tests carried out using homogeneous strings, heterogeneous strings and artificial corpus. In homogeneous string compression, both algorithms have the same advantages because the value of CR, SS and bit rate are the same for each number of strings used. From the time of compression, Start-Step-Stop algorithm faster than the Gopala-Hemachandra algorithm. Testing of heterogeneous strings found that the Start-Step-Stop algorithm is superior to the Gopala-Hemachandra algorithm because it can save more storage space.
Publisher: IOP Publishing
Date: 06-2020
DOI: 10.1088/1742-6596/1566/1/012074
Abstract: Data security becomes an important thing in the computer era nowadays, especially in digital lock. Because of easy to use, there is a lot of digital locks connected to Android smartphone. However, the security of digital lock is lower if commands and passwords exchange is unprotected. That is why algorithm combination concept is important to be applied. Vigenere Cipher and XOR Cipher algorithm combination is simple to be applied, where both are symmetric cryptography algorithm which has advantage in short calculation time, so the plaintext processing can run quickly. To implement the cryptography algorithm combination concept, a digital lock prototype is also needed. One of the best microcontroller for prototyping is Arduino UNO. It can communicate with other devices through Bluetooth connection especially Android smartphone if connected to Bluetooth module. The Arduino UNO based digital lock will communicate with Android smartphone via an application in the smartphone. It is found that Vigenere Cipher and XOR Cipher algorithm combination, and also other support algorithms can improve the secrecy of communication between devices in the digital lock system.
Publisher: IEEE
Date: 07-2020
Publisher: IOP Publishing
Date: 08-2019
DOI: 10.1088/1742-6596/1255/1/012034
Abstract: One of the problems in this field of communication is the insecurity of messages sent across computer networks. Even though sometimes the contents of a message can be something that is sensitive and prone to abuse. One method that can be used to overcome this problem is by using a combination of cryptography and steganography. In this research, an add-on menu for Mozilla application was developed to secure messages to be sent via e-mail using Hill Cipher’s cryptographic method on messages and insert them using steganographic pixel value differencing method on image files to be extracted and returned to the form originally. The results of this study indicate that with experiments using messages with length and image file extensions that are also different, namely. bmp, .jpg, .png, and .gif can insert the initial message into the image file and be returned to its original form with a maximum length limit message 1000 characters and no manipulation of the image file from the insertion message.
No related grants have been discovered for Mohammad Andri Budiman.