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: Penyandian File Teks Menggunakan Algoritma AES (Advanced Encryption Standard)
Abstrak: Perkembangan teknologi dan informatika saat ini sangatlah pesat, sehingga diperlukan adanya kriptografi sebagai upaya pengamanan data. Algoritma Advanced Encryption Standard (AES) termasuk ke dalam sistem kriptografi modern yang simetris. Algoritma AES yang umum dipakai saat ini adalah AES-128, AES-192 dan AES-256. Penelitian ini merekonstruksi tahapan-tahapan algoritma AES baik secara teknis implementasi maupun konsep matematika yang digunakan, serta menerapkan algoritma AES dalam penyandian file teks dan mengukur run-time algoritma tersebut. Algoritma AES diawali dengan mengubah plaintext menjadi sejumlah blok teks berukuran 128 bit, serta melakukan proses key scheduling untuk memperoleh sejumlah round key. Proses enkripsi meliputi AddRoundKey dengan menggunakan round key yang telah diperoleh, ShiftRows, SubBytes dan MixColumn sebanyak beberapa putaran. Proses dekripsi AES merupakan kebalikan dari proses enkripsi. Proses-proses pada algoritma AES terjadi di sebuah lapangan yang disebut Galois Field (GF(2^8)). Berdasarkan hasil yang diperoleh, waktu yang diperlukan untuk mengenkripsi dan dekripsi file meningkat secara linear tergantung pada ukuran file., The current development of technology and informatics has been advanced rapidly, hence the need for cryptography as an effort to secure data. The Advanced Encryption Standard (AES) algorithm belongs to the category of modern symmetric cryptography. The commonly used AES algorithms today are AES-128, AES-192, and AES-256. This research reconstructs the stages of the AES algorithm, both in technical implementation and the mathematical concepts employed. It also applies the AES algorithm in encoding text files and measures the algorithm's run-time. The AES algorithm starts by converting plaintext into a series of text blocks, each sized at 128 bits. It also undergoes a key scheduling process to obtain a set of round keys. The encryption process involves AddRoundKey using the obtained round key, followed by ShiftRows, SubBytes, and MixColumn for several rounds. The decryption process in AES is the reverse of the encryption process. These processes in the AES algorithm occur in a field known as Galois Field (GF(2^8)). Based on the obtained results, the time required for encrypting and decrypting files increases linearly depending on the file size.
Keyword: AES, algorithm, cryptography, Galois Field, security

Judul: Perilaku Reproduksi dan Karakteristik Mikrohabitat tempat Bertelur Burung Gosong (Megapodius reinwardtii Dummont 1823) Di Taman Buru Pulau Moyo
Abstrak: Burung gasang (Megapodius reinwardtii) merupakan jenis burung terestrial yang selalu berpasangan sepanjang hidupnya. Burung ini dilindungi berdasarkan SK Menteri Kehutanan No. 882/Kpts-II/1992 tanggal 28 September 1992. Penyebaran satwa ini hanya terbatas di wilayah Indonesia bagian timur.
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