DIGITAL SIGNATURE AND
In today's commercial environment, establishing a
framework for the authentication of computer-based
information requires a familiarity with concepts and
professional skills from both the legal and computer security
Thus digital signatures are used. Signatures are nothing but
mark of authenticating any document.
Why do we need verification?
A leading Japanese company has found a way to get your
DNA into a pen. You sign a document and it is digitally
Identity should be verified when ever there is doubt of the
3rd party being whom they say they are or when there is
personal information at risk.
Personal information like credit card details and banking
information should be kept safe using digital certification as
one of the security layers.
Digital signatures are a way to ensure the integrity of a
message or other data using public key cryptography.
Digital signatures help organizations sustain signer
authenticity, accountability, data integrity and non-
repudiation of documents and transactions.
Components of digital signature:
Name and e-mail address:
Expiration date of the public key :
Name of the company :
Serial number of the Digital ID:
Digital signature of the CA (certification Authority):
Signatures and Laws:
Efficiency and logistics :
DIGITAL SIGNATURE WORKS ON THE
A Singing algorithm
A key generation algorithm
A verification algorithm
. When a message with a digital signature is transmitted and
received, the following parties are involved:
1) The signer who signs the document;
2) The verifier who receives the signed document and verifies the
3) The arbitrator who arbitrates any disputes between the signer
and the verifier if there is a disagreement on the validity of
the digital signature.
DIGITAL SIGNATURE STANDARD
This Standard specifies a Digital Signature Algorithm (DSA)
appropriate for applications requiring a digital rather than
written signature. The DSA digital signature is a pair of
large numbers represented in a computer as strings of binary
The DSA provides the capability to generate and verify
A hash function is used in the signature generation process to
obtain a condensed version of data, called a message digest .
The message digest is then input to the DSA to generate the
digital signature. The digital signature is sent to the intended
verifier along with the signed data (often called the message).
The verifier of the message and signature verifies the
signature by using the sender's public key.
The same hash function must also be used in the verification
process. The hash function is specified in a separate standard,
the Secure Hash Standard (SHS), FIPS 180.
A digital certificate contains:
The user's distinguished name (a unique identifier)
The issuing Certification Authority's distinguished name
The user's public key
The validity period
The certificate's serial number
The issuing Certification Authority's digital signature,
verifying the information in the digital certificate.
PROBLEMS IN DIGITAL SIGNATURE:
Imposters, by minimizing the risk of dealing with imposters
or persons who attempt to escape responsibility by claiming
to have been impersonated;
Message integrity, by minimizing the risk of undetected
message tampering and forgery, and of false claims that a
message was altered after it was sent;
Formal legal requirements, by strengthening the view that
legal requirements of form, such as writing, signature, and an
original document, are satisfied, since digital signatures are
functionally on a par with, or superior to paper forms.
Digital watermarking is a technique which allows an
individual to add hidden copyright notices or other
verification messages to digital audio, video, or image signals
and documents. Such hidden message is a group of bits
describing information pertaining to the signal or to the
author of the signal (name, place, etc.).
TYPES OF WATERMARKING:
VIDEO WATERMARKING: The watermark image is
inserted into the video media.
AUDIO WATERMARKING: The audio media is used to
insert the information.
TEXT WATERMARKING: The text media is used to insert
the information .
Types of watermark.
How to create watermarking image
Digital Watermarking software looks for noise in digital
media and replaces it with useful information. A digital
media file is nothing more than a large list of 0’s and 1’s.
The watermarking software determines which of these 0’s
and 1’s correspond to redundant or irrelevant details.
For example, the software might identify details in an image
that are too fine for the human eye to see and flag the
corresponding 0’s and 1’s as irrelevant noise. Later the
flagged 0’s and 1’s can be replaced by a digital watermark.
LIMITATIONS OF WATERMARKING:
-> There will likely be non-commercial applications,
or those with limited vulnerability to theft,
where "good enough watermarking" will suffice.
all watermarking techniques will be useful in resolvingo
ownership disputes in the court
FUTURE OF WATERMARKING:
The challenge is to develop ever more invisible,
decodable, and permanent watermarking methods,
and perhaps to meet even more specifications as they
Digital watermarking can successfully be employed if
the value of the digital media warrants the added
expense. If not, it is an exercise in futility.
Digital signatures have gained popularity in past
years and now it is used in many organization,