A digital signature is a type of electronic signature where a mathematical algorithm is routinely used to validate the authenticity and integrity of a message (e.g., an email, a credit card transaction, or a digital document). Digital signatures create a virtual fingerprint that is unique to an individual or entity and are used to identify users and protect the information in digital messages or documents and ensure no distortion occurs when in transit between signer and receiver. In emails, the email as a whole also becomes a part of the digital signature. Digital signatures are significantly more reliable and secure than other forms of electronic signatures.

Digital Signature Authentication:

• A digital signature is a mathematical arrangement to verify the authenticity of digital documents or messages.
• Like written signatures, digital signatures provide verification of the associated input or messages.
• Further, digital signatures authenticate the source of messages like an electronic mail or a contract in electronic form.
• They authenticate the source of messages.

Advantages of digital signatures

• Saves time: You no longer have to wait for your manager to return from a holiday or conference for that signature. Digital signatures ensure that businesses save on cost and time with documents and contracts signed off with a click of a button. There are huge savings in cost and time especially when the person required to sign is in a geographically different area. Documents can be signed off almost instantly, from anywhere. Be it a tablet, phone or computer, digital signatures can seamlessly ensure this otherwise tedious task is wrapped up in minutes.
• Cost savings: Many companies also see significant cost savings, with little or no expense in ink, paper, printing, scanning, shipping/delivery, or travel expenses. There are also savings in other indirect costs such as filing, rekeying data, archiving, or tracking.
• Workflow efficiency: With lesser delays, digital signatures ensure better efficiency in workflow. Managing and tracking documents are made easier, with lesser effort and time involved. Many features of digital signatures help speed up the work process. For instance, email notifications help remind the person to sign, while status tracking helps to know at which stage the document is at.
• Better customer experience: Digital signatures provide the convenience of signing important

documents wherever a customer or the person to sign is located. Salespersons do not have to wait for the customer to come to the bank or office. Documents can be signed off at the doorstep. This is ideal, especially in remote areas and smaller townships providing improved and personalized services. The customer has the freedom to be anywhere, and engage with a company, making services and businesses far more easy, quick, and user-friendly.

• Security: When it comes to signatures, authenticity, and security are a priority. Digital signatures reduce the risk of duplication or alteration of the document itself. Digital signatures ensure that signatures are verified, authentic and legitimate. Signers are provided with PINs, passwords, and codes that can authenticate and verify their identity and approve their signatures. Time stamping provides the date and time of the signature and thus provides a track of the document, minimizing any risk of tampering or fraud. Security features embedded in digital signatures ensure that documents have not been altered without authorization.
• Legal validity: Digital signatures provide authenticity and ensure that the signature is verified. This can stand in any court of law like any other signed paper document. Time stamping and the ability to track and easily archive documents improve and simplify audit and compliance.

Hence, digital signature is becoming increasingly used as a method of authenticating paper. But there are issues of rising cyber security related threats, and it has become one of the serious challenges in making digital signature universal. India needs to secure its cyberspace so that no one can breach authentication of digital signature and trust on digitally signatured papers remain.

India embarked on developing space science and technology in an era when it was being criticized for spending money on such expensive technologies when its priority should be fighting rampant poverty that prevails.. In 1962, Indian National Committee for Space Research (INCOSPAR) was established as a precursor to ISRO. Dr. Vikram Sarabhai, having identified the role and importance of space technology in a Nation's development, provided ISRO the necessary direction to function as an agent of development. In 1972 the Government of India constituted a space commission and the Department of Space was established. Both the institutions regulate and give directions to India's space programme.

India's achievements in the field of Space S&T:

• Mars Orbiter Mission: India's first inter planetary mission, the Mars Orbiter Spacecraft was

successfully launched onboard PSLV-C25. It made India to become one of the four nations in the world to send space mission to Planet Mars. Mars Orbiter Mission is mainly intended to establish the Indian technological capability to reach Martian orbit and to explore Mars surface features, morphology, mineralogy and Martian atmosphere by indigenous scientific instruments.

• ASTROSAT: India's first multi wavelength observatory capable of simultaneously viewing the Universe in the visible, Ultraviolet and X-ray regions of the electromagnetic spectrum.
• PSLV - A Workhorse Launch Vehicle: India's Polar Satellite Launch Vehicle (PSLV), with a proven track record of 24 successful flights, has provided the country crucial autonomy in 'access to space'. During the last decade, PSLV had 15 successively successful flights and has placed 23 Indian satellites and 31 foreign satellites into orbit.
• India's Mission to Moon: India's maiden moon exploration mission 'Chandrayaan-1' was launched in October 2008 for mapping the lunar surface with high resolution remote sensing and studying the chemical and mineralogical composition. This mission has enabled the detection of the presence of water molecules on the lunar surface, which has set new directions for lunar explorations in the global community. Recently Chandrayaan 2 successfully put an orbiter in the moon's orbit but failed to do a soft landing on the moon.
• SATCOM & SATNAV Applications: Doordarshan is presently operating 34 satellite channels and has a vast network of 67 Studios and 1,409 Transmitters installed throughout the country.
• Indian Cryogenic Engine & Stage: The successful flight testing of indigenous cryogenic stages onboard GSLV-D5 Flight. Geosynchronous Satellite Launch Vehicle (GSLV) is capable of placing 2 Tonne class communication satellite into Geosynchronous Transfer Orbit (GTO) and India is one among six countries in the world to demonstrate such launch capability to GTO with the use of complex cryogenic technology.
• Flood maps were provided for flood affected states during the monsoon season. Flood Early Warning System (FLEWS) is one of the operational programmes taken up by NESAC at the behest of Assam State Disaster Management Authority (ASDMA).
• Remote Sensing and National Natural Resource Management System: The Indian Remote Sensing Satellites (IRS) System, with currently 11 satellites in orbit, is one of the largest constellations of remote sensing satellites in operation in the world today. It provides inputs for management of natural resources and various developmental projects across the country using space based imagery.
• Space Capsule Recovery: A leap-frog in Indian Launch Vehicle Technology was achieved in 2007 through the Space Capsule Recovery Experiment Mission SRE-1 which established India's technological capability to recover an orbiting satellite with precise re-entry trajectories.

Socio-Economic development through the application of space technology:

• Telecommunication and Digital revolution: Increased penetration of tele networks and satellite services for broadband and entertainment.
• Resource management and conservation- These include Mines and minerals, water resources, Forest etc. with the help of remote sensing application.
• Tele education: Extended reach of education through the talk back channels of INSAT-3D satellite.
• Meteorological information: Various meteorological services including information about monsoons, climate flood, cyclonic activities, etc are provided through the technologies.
• Gramsat: The concept of "Gramsat" satellites have emerged to provide the basic requirements of villages.
• Commercial Space programs: Antix- as an arm of ISRO aims to establish itself as a competitive player in the low-cost satellite market. Its commercial orientation has helped India earn Forex reserves.

India has demonstratively achieved successful milestones in space science and technology since independence. Space technologies have immense potential and application in various sectors for social benefits. In these ways, the space program has given a push to every aspect of our national policies and programs contributing widely towards the socio-economic development of India, besides economic and scientific progress. It is time to make the application of space technologies to everyday life. There is a lot of scope and potential in this regard.