Judul: ROSANJA. Combining Data Compression Techniques and Stream Ciphers Encryption for Digital Image Security.
Abstrak: One of the most common information form is image. Some certain images are strictly confidential, therefore, it has to be kept confidential. The process of maintaining its confidentiality is related to cryptography. Cryptography has two main components, encryption and decryption. In many cases, confidentiality is not the only issue, but also how the data is stored and transferred. To solve these issues, data compression is required. The purpose of this research is to apply data compression techniques and stream ciphers encryption for digital image, and to analyze the result. This research uses DCT method and quantization with compression level 50 (in 1-100 scale). LFSR method is used to generate a key. Then, PSNR value of the decrypted image is calculated. As a result, this research shows that the compression process affects encryption time, the time required to encrypt and decrypt an image is getting longer as the size of the image grows.
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Judul: Analisis Beragam Skenario Enkripsi pada Gambar Digital Berwarna Menggunakan Algoritme Data Encryption Standard (DES)
Abstrak: Cryptographic techniques are widely applied to maintain the confidentiality of a message. However, most cryptographic techniques are currently still being performed on the entire content of the message, so that they require high computation time. Therefore, in this research we designed several test scenarios to encrypt partially the contents of the messages which can lead to faster computation while still maintaining the quality of information confidentiality. In this research, we used BMP image files of digital color photographs with color depth 24-bit consisting of three different objects. Encryption technique used is Data Encryption Standard (DES) with operating mode Electronic Codebook (ECB). Analysis is performed on computation time and quality of the encryption of each scenario. The quality of encryption is computed using Peak Signal to Noise Ratio (PSNR) and a survey to 30 respondents. Respondents will compare the original image file (plaintext) and encrypted image (ciphertext). Results of the analysis showed that the computation time is not only affected by the resolution of image files but also by the choice of the encryption scenarios. The encryption with the best, indicated by the smallest PSNR values was generated by the scenario 1 (scenario full) with the average value of 33,62 dB, while the largest PSNR value was generated on the scenario 8 (head section) with an average value of 39,67 dB. Encryption quality visually assessed based on the results of the survey. The results of the survey concluded that, the best encryption quality was achieved in scenario 1 with a value of 93,33%, and the worst in scenario 7 (bottom scenario) with a value of 28%. In this research, the computation time of scenario 8 is one third of the computation time of scenario 1. Conclusions obtained from this research is that by applying the appropriate encryption scenario, shorter computation time can be achived while maintaining effective encryption.
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Judul: Study of Tupaia javanica Hepatocytes Culture as In Vitro Replication Media of Nonhuman Primate HBV
Abstrak: Virus hepatitis B (VHB) adalah virus DNA yang menginfeksi organ hati sebagai target utama. Infeksi ini menyebabkan hepatitis yang dapat bersifat kronis dan berlanjut menjadi sirosis, kanker hati bahkan kematian. Pengembangan model in vivo dan in vitro berkaitan dengan hepatitis B menjadi perhatian khusus bagi para peneliti. Kultur hepatosit banyak digunakan untuk mempelajari berbagai ha] terkait hepatitis B baik dari aspek virus, penyakit, pencegahan, dan pengobatan. Pengembangan hepatosit asal hewan kecil sepe1ii Tupaia sp. untuk model in vitro merupakan salah satu altematif dalam penyediaan kultur hepatosit. Tujuan penelitian ini adalah mengembangkan kultur primer dan lestari hepatosit T. javanica yang mampu mendukung replikasi VHB orangutan (OuHBV) dan VHB owa jawa (GiHBV), dan dapat menjawab kebutuhan akan model in vitro kultur hepatosit. Isolasi hepatosit T. javanica dilakukan dengan prosedur sebagai berikut: organ hati yang telah dicacah dalam cawan petri dengan larutan perfusi, diinkubasi pada 37 °C. Suspensi disentrifugasi 300-500 g sehingga didapatkan pelet sel hati. Pelet yang sudah dicuci kemudian diresuspensi dengan Hepatocyte Basal Media untuk menumbuhkan hepatosit dan selanjutnya hepatosit akan ditransformasi menggunakan perangkat Lenti-SV 40. Sodium taurocholate cotransporting polypeptide (NTCP) yang diindikasikan sebagai reseptor hepatosit untuk melekatnya VHB, nampak pada hepatosit baik pada kultur primer maupun kultur yang ditransformasi. Reseptor hepatosit spesifik ini terlihat sebagai pendaran hijau dengan uji imunofluoresensi. Kultur hepatosit primer T. javanica berhasil dikembangkan selama 14 hari untuk mencapai kepadatan 80%, dan inokulasi GiHBV dan OuHBV ke dalam kultur pada hari ke-15 menunjukkan adanya replikasi virus hingga hari ke-8 (berdasarkan hasil PCR). Kuantifikasi virus dengan real-time PCR memperlihatkan replikasi tertinggi pada hari kedua setelah inokulasi. Penjajaran sebagian protein permukaan setelah virus dinokulasikan memperlihatkan kesamaan asam amino dengan virus wild type sebesar 99.29% dan 95.71 % pada GiHBV dan OuHBV., Hepatitis B virus (HBV) is a DNA virus which infects liver as primary target organ. This i11fection causes hepatitis which could become chronic and progress to cirrhosis, liver cancer and even death. Development of in vitro and in vivo model related to hepatitis B is a concern for researchers. Hepatocyte cultures widely used to study a variety of aspects of hepatitis B such as the virus, disease, prevention and treatment. Development qf hepatocyte from small animal e.g. Tupaia sp. for the in vitro model is an alternative of hepatocyte cultures. The purpose of the study is to develop primary and immortal T. javanica hepatocytes cultures capable to replicate orangutan HBV (OuHBV) and javan gibbon HBV (GiHBV), and to answer the need for in vitro model ofhepatocytes. Isolation of hepatocytes from T. javanica was done as followed: mincedliver were transported into petri dish containing perfusion buffer solution to be incubated at 37 °C. The suspension was centrifuged at 300-500 g to obtain liver cell pellets. The washed-pellet was resuspended in Hepatocyte Basal Media to let specific hepatocytes grow and later be transformed by Lenti-SV40 kit. Sodium taurocholate cotransporting polypeptide (NTCP) has been ident(fied as hepatocyte receptor for HBV attachment, and was seen on hepatocytes from both primary and transformed cultures. This hepatocytes specific receptor was shown as green luminenscent by immunofluorescence assay. Primary T. javanica hepatocytes cultures was successfully maintained for
Keyword: Tupaia javanica, in vitro model, hepatocytes culture, hepatitis B virus, Liver cancer, Picornaviridae, Hepadanaviridae, Flaviviridae, Caliciviridae