Judul: Running Time Test of IDEA Algorithm in Encryption and Decryption Data process.
Abstrak: International Data Encryption Algorithm (IDEA) is a symetric and cipher block cryptographic algorithm. This algorithm operates in the form of bit block with the block size of 64 bits. The objective of this research is to measure the performance of IDEA based on the execution time (ms) and memory usage (KB) at the time of encryption and decryption process. The Implementation is built using JAVA programming language. The result show that increasing the size of file means increase the amount of memory usage and execution time. Keyword : Cryptography, block cipher, IDEA
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Judul: Konstruksi Kelas Kunci Lemah pada Kriptosistem IDEA Berdasarkan Faktor Linear dan Kriptanalisis Diferensial
Abstrak: Cryptography is the study of mathematical techniques related to aspects of information security such as confidentiality, data integrity, entity authentication and data origin authentication. In cryptography, a common way to secure information or document is to disguise the message you want to send a different message, then the message will be seen by those who have the authority to make the process of reversal of messages that have been disguised. The information disguises process known as cryptosystems. Cryptosystem divided into two parts : symmetric and asymmetric cryptosystems. In this thesis we study cryptanalysis of IDEA (International Data Encryption Algorithm). IDEA algorithm is an algorithm that operates with a block size of 64 bits by using the same key size of 128 bits. This algorithm uses mixed operations are multiplication modulo operation (216 + 1), addition modulo operation (216) and bitwise XOR. In this study is conducted a theoretical study relating to the construction of a weak key classes on IDEA cryptosystems and affirmation of the tables that have been created by Daemen. The construction of a weak key classes is based on linear factor and differential cryptanalysis. There are three objectives of this study, namely: (1) to assess proposition associated with the construction of a weak key classes on IDEA cryptosystems, (2) to construct a weak key classes based on factor linear and differential cryptanalysis, (3) to recover weak keys in IDEA cryptosystems. The construction of the weak key classes based on linear factor resulting global linear equations that are used to lower the chances of recovery of the bits that are not known yet. While the construction of the weak key classes based on differential cryptanalysis where at the seventh round was not required to produce a weak key class 266
Keyword: IDEA (International Data Encryption Algorithm), weak keys, linear factor, differential cryptanalysis

Judul: Sintesis Pati Sagu Tertaut Silang Fosfat sebagai Bioadsorben Pb(II).
Abstrak: Logam timbal yang berasal dari perairan dan tanah dapat masuk ke dalam tubuh dan menyebabkan berbagai masalah kesehatan. Upaya yang sudah dilakukan untuk menanggulangi keracunan timbal adalah dengan cara menjerapnya. Salah satu bahan yang berpotensi untuk dijadikan bahan penjerap timbal adalah pati sagu tertaut silang fosfat (SgP). Untuk itu, penelitian ini bertujuan menentukan kondisi terbaik sintesis SgP dan kapasitas adsorpsi timbal oleh SgP sebagai bioadsorben dalam sistem pencernaan manusia secara in vitro. SgP disintesis pada suasana asam mengunakan pereaksi Na2HPO4:NaH2PO4 (3:2). SgP dengan nilai derajat substitusi fosfat tertinggi disintesis pada pH 6, suhu 30 oC, selama 30 menit, dan kecepatan pengadukan 100 rpm. Walaupun berpotensi sebagai penjerap timbal, kapasitas penjerapan SgP terhadap timbal lebih rendah dibandingkan dengan kapasitasnya untuk menjerap merkuri. Uji in vitro dilakukan pada beberapa kondisi yang sesuai dengan sistem pencernaan manusia. Kemampuan penjerapan timbal terbaik oleh SgP terjadi pada pH 8.6 yang merupakan kondisi pada usus kecil.
Keyword: adsorbsi, pati, sagu, taut silang, timbal