Judul: Analysis and implementation feldman verifiable secret sharing scheme
Abstrak: Informasi yang bersifat rahasia membutuhkan penjagaan supaya tidak dapat diakses oleh pihak yang tidak berkepentingan. Salah satu cara untuk menjaganya adalah dengan menggunakan skema pembagian rahasia. Skema pembagian rahasia yang diverifikasi merupakan perkembangan dari skema pembagian rahasia. Skema Shamir adalah salah satu contoh dari skema pembagian rahasia yang didasari oleh interpolasi Lagrange. Skema Feldman merupakan perbaikan dari kelemahan yang dimiliki oleh skema Shamir. Skema Feldman juga merupakan salah satu contoh dari skema pembagian rahasia yang diverifikasi. Penelitian ini bertujuan untuk menjelaskan cara kerja pembagian rahasia menggunakan skema Feldman, menerapkan skema Feldman dalam pembagian rahasia menggunakan perangkat lunak Wolfram Mathematica 10, dan menganalisis keamanan skema Feldman. Tahapan skema Feldman terdiri atas dua bagian yaitu pembagian kunci dan penyusunan kunci. Tahap pembagian kunci terdiri atas tahap penentuan parameter dan tahap distribusi, sedangkan tahap penyusunan kunci terdiri atas tahap verifikasi dan tahap penyusunan ulang. Skema Feldman memiliki kebocoran mengenai rahasianya karena nilai dari komitmen yang diberikan secara umum. Hal tersebut tidak terlalu dipermasalahkan, karena upaya mendapatkan rahasia dari kebocoran tersebut harus menggunakan logaritma diskret yang masih tak layak untuk dipecahkan., Confidential information requires a protection such that it cannot be accessed by unauthorized parties. One way to keep it safe is by employing a secret sharing scheme such as Shamir’s scheme which developed based on Lagrange interpolation. Verifiable secret sharing scheme is an improvement of secret sharing scheme, such as Feldman’s scheme which overcomes the weakness of Shamir’s scheme. The purposes of this study are to describe the secret sharing mechanism by using the Feldman’s scheme, to apply Feldman’s scheme in sharing secret by using Mathematica 10, and to analyze the security aspect of Feldman’s scheme. Feldman’s scheme consists of two stages, namely key distribution and key preparation. Key distribution comprises the step of determining parameters and distribution phase, whereas key preparation consists of verification and reconstruction phases. Even though Feldman’s scheme might have a leak about the secret because of the value from commitments given in general, it is not too problematic, because to get the secrets from the leak we must perform a discrete logarithm which is infeasible from the perspective of computation.
Keyword: interpolasi Lagrange, logaritma diskret, skema pembagian rahasia, skema pembagian rahasia yang diverifikasi

Judul: Analisis dan Implementasi Pembagian Rahasia Menggunakan Skema Ambang Shamir
Abstrak: key is used to keep secret in order not easily accessible by others. The key itself also requires a way to keep it from accessed by someone else. A threshold secret sharing scheme developed by Adi Shamir is one way to keep a secret key. This scheme's objective is to divide a secret key S into n parts, such that S is easily reconstructed from any t parts, but when less than t parts are known there is no information about the secret key can be obtained. This research's objectives are to explain how to share a secret using Shamir's threshold scheme, to analyze the security of Shamir's threshold scheme, and to implement Shamir's threshold secret sharing scheme using Wolfram Mathematica 10. Shamir threshold scheme consists of two stages, namely sharing stage and reconstruction stage. This scheme is computationally secure, since it works on integers modulo p, so that when only t – 1 parts of the secret number are known, it is very difficult to guess the value of S.
Keyword: Bogor Agricultural University (IPB), Lagrange interpolation, secret sharing scheme, cryptography

Judul: Populasi dan Habitat Kakatua-Kecil Jambul-Kuning di Bentang Alam Mbeliling Bagian Barat, Kabupaten Manggarai Barat, Nusa Tenggara Timur
Abstrak: Cacatua sulphurea parvula or yellow-crested cockatoo were spread distributed at Sunda Kecil Archipelago, Nusa Tenggara, except at Sumba Island. This species amount in the nature is very small, caused by the illegal hunting and trading. The purpose of this research is to get the information about population and habitat of the cockatoo in Flores, especially at the western part of Mbeliling Landscape. Cocatoo census was conducted by look-down method at vantage points when cockatoo flew passed by. Habitat analysis was carried out with vegetation analysis. The census showed that there were two groups of cockatoo, consisted of 69 cockatoos in Tao hill and 15 cockatoos in Nggoer River. Flight pattern of each group ranged 0-100 meters above the sea level and crossed mangrove forest, savanna, monsoon forest and cultivation plant vegetation. The vegetation analysis resulted Ceiba petandra or silk-cotton tree as the tree that most used by cockatoo and had the highest TIV (Tree Importance Value), 47,48%. Cockatoo’s foods which observed were crown flower (Calotropis gigantea), and Moringa olifera. The population of Cockatoo which observed at western part of Mbeliling Landscape was estimated came from Rinca Island, Komodo National Park. It can be concluded that the location might be only used by rhe cockatoo came from Rinca Island as their daily exploration area for foraging.
Keyword: habitat., ecology, population, Flores, Cacatua sulphurea parvula