Message Security Using a Combination of Hill Cipher and RSA Algorithms

The process of exchanging digital messages is increasingly being used due to its easy and practical use. But the process of exchanging digital messages is vulnerable to being tapped by unauthorized people. Cryptography is the study of mathematical techniques related to aspects of information security, such as data confidentiality, data validity, data integrity, and data authentication. With cryptography, the process of exchanging messages between two people can be done securely. Thus, cryptographic techniques are used to overcome security issues when exchanging messages. The methods used in this study are hybrid hill cipher and RSA cryptography. In this study it was shown that hybrid hill cipher cryptography with a 3x3 matrix key and RSA with a 512 bit key can overcome security issues when exchanging data so that messages sent cannot be read by unauthorized people.

Making Oxalic Acid From Palm Oil Pelepah (Elaeis Guineensis) Through Nitric Acid Oxidation Reaction

Palm oil palm is one of the solid waste produced by oil palm plantations every harvest. Chemical analysis of palm oil palm oil pellets showed that there are components of cellulose, hemiscellulose, and lignin that show that palm oil pellets have the opportunity to be further processed into useful and economically valuable products. Palm waste contains cellulose by 34.89%, hemiscellulose by 27.14%, and lignin by 19.87%. The analysis conducted on raw materials includes the analysis of water content and cellulose levels of palm oil palm oil. 46.6% and cellulose levels of 29.2%. In this study quantitative analysis was conducted in the form of cellulose conversion and oxalic acid yield. The largest cellulose conversion was obtained at the use of 70% nitric acid concentration and 80 minutes reaction time of 58.56%.

Boosting Stemmer Performance Using Cache Method

Stemming is the process of returning the word to the base word by disappearing the append. This is important to support better information re-meeting. Some research in stemming algorithms includes nazief &adriani algorithms, confix stripping, enhanced confix stripping, arifin and porter algorithms. The stemming algorithm for Bahasa Indonesia is divided into two, namely those that use a dictionary and do not use a dictionary. Some studies have shown that stemmers that use dictionary have high accuracy but low process speed, while stemmers that do not use dictionary have low accuracy but higher process speed. In this study, two methods were used: the stemmer method using cache and stemmer without cache to see the comparison of process speed from stemmers that use dictionary. The test data for this study is text data obtained from the corpus site. Process analysis is completed by calculating each speed, memory usage and cpu of each method, then each method is compared. Results from tests from test data showed that the cache method improved stemmer performance.

Manufacture and Characterization of Pineapple Leaf Fiber Composite Board With Polypropylene Adhesive

Research has been conducted on the manufacture and characterization of pineapple leaf fiber composites – polypropylene matrix. Samples with comparison of pineapple leaf fiber composition: polypropylene matrix by 0 %: 100%, 5%: 95%, 10%:90%, 15%:85%, 20%;80%, and 25%:75%. The manufacture of SDN-PP composites, i.e. fiber soaked with NaOH 5% for 2 hours and then rinsed with clean water and dried, then weighed. Polypropylene and MAPP are effluxed with xylen solvent using a reflux device over a hot plate with a temperature of 17oC until melted. The polypropylene that has been diflux weighed in mass and pineapple leaf fibers are placed into a mold then pressed with a hot press at a temperature of 150oC for 30 minutes. The purpose of the study was to find out the physical and mechanical properties of pineapple leaf-matrix polypropylene fibers. Density values 0.75 g/cm3 to 0.9 g/cm3, water absorption values 0.54% to 14.38%, strong compressive values 25.09 MPa to 49.58 MPa, and strong values impact 9.74 J/mm2 to 34.18 J/mm2. Pineapple leaf fiber composite – the resulting polypropylene matrix can be categorized as a high-crust fiberboard (HF) and applied as a decorative board in accordance with the fiberboard standards set out in SNI 01-4449-2006.

The Effect of Mount Sinabung Volcanic Dust Mixture on The Strength of Construction Ceramics

It has been made of construction ceramics using the volcanic dust of Mount Sinabung combined with kaolin, clay, feldspar and water as a mixture. with the composition of kaolin, feldspar, clay, volcanic dust of Mount Sinabung. Sample making is done starting with the sifting stage of 100 mesh materials and mixing materials up to homogeneous 15 minutes, printing with a 5 ton emphasis with a temperature combustion of 1100oc and in hold for 2 hours. With the characteristics of construction ceramics has been tested that is shrinkage mass 6.99-13.53%; porosity 4.84-10.46%; strong press 2.5-14.6 Mpa; hardness 84.7-169.6 kgf/mm2.