Informatics Publishing Limited

R. Venkateswaran ¹, V. Sundaram ²

Affiliations
1 GR Govindarajulu School of Applied Computer Technology, Coimbatore, TN, IN
2 Department of MCA, Karpagam College of Engineering, Affiliated to Anna University of Technology, Coimbatore, TN, IN

Abstract

This paper shows the possibility of exploiting the features of substitutions cipher with ASCII values of the given text and then applying conversion, transposition and shows some unreadable form. In substitution ciphers the plaintext letters are enciphered differently depending upon their placement in the text. As the name polyalphabetic suggests this is achieved by using several two, three keys and random keys combinations instead of just one, as is the case in most of the simpler crypto systems. Using two keys, we take 2 keys e1, e2 and let the ASCII values of e1 be 1 and e2 be 2 and take the text, add ASCII values of e1 to first character and ASCII values of e2 to second character. Alternatively add the value of e1 and e2 to consecutive characters. Here we introduced security layer that is user can select their security level based on their communication over Internet.

Keywords

Encryption, Decryption, Genetic Keys, Mono Substitution, Poly Substitution, Ciphers.

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B. Raghavendra Prasad ¹, Dipankar Banerjee ¹, Jagdev Singh ¹, S. Nagabhushana ¹, Amit Kumar ¹, P. U. Kamath ¹, S. Kathiravan ¹, Suresh Venkata ¹, N. Rajkumar ¹, V. Natarajan ¹, Madhur Juneja ¹, Pawan Somu ¹, Vaibhav Pant ¹, Nigar Shaji ², K. Sankarsubramanian ², Asit Patra ³, R. Venkateswaran ⁴, Abhijit Avinash Adoni ², S. Narendra ², T. R. Haridas ⁵, Shibu K. Mathew ⁶, R. Mohan Krishna ², K. Amareswari ², Bhavesh Jaiswal ²

Affiliations
1 Indian Institute of Astrophysics, 2nd Block, Koramangala, Bengaluru 560 034, IN
2 ISRO Satellite Centre, Old Airport Road, Vimanapura Post, Bengaluru 560 017, IN
3 Space Applications Centre, Jodhpur Tekra, Ambawadi Vistar, P.O., Ahmedabad 380 015, IN
4 Laboratory for Electro-Optics Systems, First Phase, Peenya Industrial Estate, Bengaluru 560 058, IN
5 ISRO Inertial Systems Unit, Vattiyoorkavu PO, Thiruvananthapuram 695 013, IN
6 Udaipur Solar Observatory, Near Fatehpur Lake, Shilpgram, Udaipur 313 004, IN

Abstract

Solar coronagraph mimics total solar eclipse by blocking the solar disk and enabling the observation of extended coronal atmosphere of the Sun. Visible Emission Line Coronagraph (VELC), on-board Aditya-L1 space mission, is an internally occulted solar coronagraph capable of simultaneous imaging, spectroscopy and spectro-polarimetry close to the solar limb. This payload is designed to study the coronal plasma and heating of the solar corona. Studying development, dynamics and origin of coronal mass ejections and measurement of coronal magnetic fields over active regions are other important science goals. VELC is designed to image the solar corona at 500 nm with an angular resolution of 5" over a field of view (FOV) of 1.05-3 R_o. It also facilitates simultaneous multi-slit spectroscopy at three emission lines, viz. Fe XIV (530.3 nm), Fe XI (789.2 nm) and Fe XIII (1074.7 nm) with a spectral resolution of 28 , 31 and 202 mÅ/pixel respectively, over an FOV of 1.05-1.5 R_o. The payload has a dual-beam spectro-polarimetry channel for magnetic field measurements at 1074.7 nm.

Keywords

Coronagraph, Coronal Mass Ejection, Payload, Solar Corona.

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