Knowlegde Through Fun Welcome To Mady's Site.

The authenticity of many legal, financial, and other documents is
determined by the presence or absence of an authorized handwritten
signature. The recipient of the signed document can verify the claimed
identity of the sender using the signature. Also, if the sender later
repudiates the contents of the document, then recipient can use the
signature to prove the validity of the document.

With the computerized message systems replacing the physical
transport of paper and ink documents, an effective solution for
authentication of the electronic data is necessary. Various methods
have been devised to solve this problem, but the use of 'digital
signature' is definitely the best solution amongst them.

A digital signature is nothing but an attachment to any piece of
electronic information, which represents the content of the document
and the identity of the originator of that document uniquely. The
digital signature is intended for use in electronic mail, electronic
funds transfer, electronic data interchange, software distribution,
data storage, and other applications which require data integrity
assurance and data origin authentication.

When a message is received, the recipient may desire to verify that
the message has not been altered in transit. Furthermore, the
recipient may wish to be certain of the originator's identity. Both of
these services can be provided by the digital signature. A digital
signature is an electronic analogue of a written signature in that the
digital signature can be used in proving to the recipient or a third
party that the message was, in fact, signed by the originator. Digital
signatures may also be generated for stored data and programs so that
the integrity of the data and programs may be verified at any later
time.

Although there are various approaches to implement the digital
signature, this report discusses the 'Digital Signature Standard'. It
specifies the Digital Signature Algorithm (DSA) which is appropriate
for applications requiring a digital rather than written signature.
The DSA is considered as the standard procedure to generate and verify
digital signatures. A DSA digital signature is a pair of large numbers
represented in a computer as strings of binary digits.

The first section of this report deals with the basic requirements
for using the digital signature. The next sections contain detailed
explanation of the process of generation and verification of the
digital signature. In addition to this the applications of the digital
Signature are also discussed. The report also focuses on some legal
aspects of digital signature, with reference to the Information
Technology Act. The use of digital signature has been illustrated with
an example in a practical scenario.

This report is an attempt to make the readers familiar with the
concepts related to the digital signature and give them an idea of
usefulness of a digital signature in the world of electronic
information exchange.