Let us start with the news section overview of cryptography.
In this video, I'm going to give you a general overview, an introduction to what is cryptography?
Cryptography is the practice and study of hiding information.
It is sometimes called code, but this is not a really correct name.
It is the science used to try to keep information secret and safe, modern cryptography is a mix of
mathematics, computer science and electrical engineering.
Cryptography is used in ATM cards, computer passwords and even shopping on the Internet.
It is a matter of storing and transmitting data in a particular form so that only those for whom it
is intended can read and processing.
Cryptography not only protects data from theft or attrition, but can also be used for user authentication.
This process is called encryption and has been used for centuries to prevent handwritten messages from
being read.
But unintended response to the cryptography is used to protect digital data.
It is a division of computer science that focuses on transforming data into formats that cannot be recognized
by unauthorized users.
An example of basic cryptography is an encrypted message in which letters are replaced with other characters.
To decode the encrypted contents, you will need a grid of tables, basically incident and the suffix
graffy stands for writing in computer science.
Cryptography refers to secure information and communication techniques derived from mathematical concepts
and a set of rule based calculations called algorithms.
These deterministic algorithms are used for cryptographically generation digital signing verification
to protect data privacy, web browsing on Internet and confidential communications such as credit card
transactions and email.
Cryptography is probably the most important aspect of communications security and is becoming increasingly
important as a basic building block for computer security.
Modern cryptography concerns itself with the four objectives confidentiality, integrity and repudiation
and authentication.
Let us have a look at Sir William Starling's conventional model.
Cryptography involves two phrases encryption and decryption, and encryption is the process through
which one can convert the plain text into encoded text.
Let's call it the ciphertext.
By using encryption algorithms.
These algorithms are public.
This ciphertext is then decoded into plain text through decryption by using decryption algorithms.
But more data is needed to be transmitted from one end to another, the same, the kind words plaintext
in the ciphertext, the receiver, upon receiving this ciphertext, decoded into plain text.
By doing this, no third party can get access to the message and even he or she gets the message that
it is not possible to decode until and unless they have access to the keys in this whole process of
encoding and decoding what the party uses either same or different keys in their algorithms.
Well, here's the simplest way to understand cryptography.
Imagine you're sending someone a letter in the mail, but you only want the person you're sending it
to read the message.
Maybe you're sending something private and you want make sure that no one looks inside the message with
cryptography.
Imagine spreading the letter into a hundred pieces before you send it, and then once it gets to the
desired recipient, it automatically reassembled itself.
The only difference is that with cryptography, it's more like you are sharing 10 billion pieces.
Perhaps the most advanced cryptography in the ancient world was achieved by the Romans.
A prominent example of Roman cryptography known as Caesar Cipher involves shifting the letters of an
encrypted messaging by a certain number of places down the Latin alphabet.
Knowing this system and a number of places to send the letters, a recipient could successfully decode
otherwise illegible message in the next lecture.
We are going to see symmetric encryption.