In data communication systems, digital signatures are a form of electronic signature security services based on the Elliptic Curve Digital Signature Algorithm (ECDSA) which are considered resistant to certain types of attacks. Attacks on digital signature schemes aim to fake a signature or are called forgery which is said to be successful if the key pair and signature generated by the attacker are accepted by the verifier. Mathematical schemes used to prove the authenticity of messages or digital documents or guarantees that the data and information actually come from the correct source. ECDSA-based digital signatures rely on discrete logarithmic problems as the basis for mathematical calculations. Q = kP where Q and P are the points of the elliptic curve in the finite field  or  and k is a positive integer number. The hash function generated from the algorithm process is then encoded (encrypted) with an asymmetric key cryptographic algorithm. In this work use p = 149 to encrypt plain text by converting the original message using dots on a curve with the help of Python programs.

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We discuss the transmission characteristics of photonic crystal with two defect illuminated by a continuous wave of Transverse Electric (TE) mode at low terahertz frequency. To study its performance we solve numerically the corresponding Maxwell equations by means of finite difference frequency domain method. By varying the angle of incident, width of defect layer and refractive index in the second defect layer, it is found that the device exhibits a significant transmission enhancement at two wavelengths with typical changes. We also demonstrate its potential applications for biosensor platform

Telah dilakukan pendopingan Litium tantalat LiTaO3  dengan cerium oksida pada substrat Si Tipe –P (100) dengan metode chemical solution deposition dan spin coating dengan kecepatan 3000 rpm selama 30 seconds. LiTaO3 memiliki konsentrasi 2.5M dan suhu annealing 800 °C. Film tipis LiTaO3 dikarakterisasi dengan ocean optic spectroscopy. Hasil dari karakterisasi spektroskopi film lithium tantalat yang didoping cerium oksida terlihat puncak absorbansi tertinggi pada suhu annealing 800oC menghasilkan panjang gelombang 934 nm, puncak absorbansi tertinggi pada film lithium tantalat pada suhu annealing 800 oC dengan kata lain film LiTaO3 banyak menyerap energi foton dari cahaya yang mengenainya serta film tipis litium tantalat menjadi cikal bakal sensor infra merah