Cryptography is the science of writing messages in secret codes . It is about the right to privacy, freedom of speech, freedom of political association, freedom of the press, freedom from unreasonable search and seizure, freedom to be left alone Although we tend to use the words ‘code’ and ‘cipher’ interchangeably, technically they're two entirely different things. When you substitute each letter in a message for a different symbol that's a cipher. A code on the other hand means assigning a secret meaning to a word or phrase.
In its earliest form, people have been attempting to conceal certain information that they wanted to keep to their own possession by substituting parts of the information with symbols, numbers and pictures.Ancient Babylonian merchants used intaglio, a piece of flat stone carved into a collage of images and some writing to identify themselves in trading transactions. Using this mechanism, they are producing what today we know as 'digital signature.' The public knew that a particular 'signature' belonged to this trader, but only he had the intaglio to produce that signature.
encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information (in cryptography, referred to as ciphertext). In many contexts, the word encryption also implicitly refers to the reverse process, decryption (e.g. “software for encryption” can typically also perform decryption), to make the encrypted information readable again (i.e. to make it unencrypted).
Basic types of encryption may be considered asMANUAL ENCRYPTION:Manual encryption is a type that involves the use of encryption software. These are computer programs that encrypt various bits of information digitally. Manual encryption involves the user's participation completely. The files he wants to encrypt are chosen, and then an encryption type is chosen from a list that the security system provides. This is great for personal computers because it allows a user to encrypt personal files in a way that will suit him, thus protecting personal material on a computer. Transparent EncryptionTransparent encryption is another type of computer software encryption. It can be downloaded onto a computer to encrypt everything automatically. This is one of the most secure types of encryption available because it doesn't leave out anything that might be forgotten when using manual encryption. Every executable application and file created in the computer has an encrypted copy that can withstand power surges and protects information in case a computer is stolen.
Symmetric EncryptionNot all encryption is done via a computer software program. You can easily encrypt information by yourself. One of the simplest ways to do this is through symmetric encryption. Here, a letter or number coincides with another letter or number in the encryption code. You can make the code up yourself--for example, a=1, b=2 and so on. You can take any written text and substitute letters and numbers for their coded counterpart, thus encrypting the text. Asymmetric EncryptionAsymmetric encryption is a secure and easy way that can be used to encrypt data that you will be receiving. It is generally done electronically. A public key is given out to whomever you want or posted somewhere for the public to see. They can then encrypt information using the key and send it to you. This is often done when writing emails. However, to decipher the encrypted code, there is another key, a private one, that only one person has. This means that while any can encrypt the data with the public key, it can only be read again by whomever has the private key.
Mrs. Vasanthi Muniasamy
TYPES OF ENCRYPTION
METHODS OF ENCRYPTION
Science of encryption and decryption; converting
between plaintext and ciphertext
Conversion of data into a form, called a ciphertext
To make encrypted information readable again
Ancient Babylonian merchants used intaglio
A piece of flat stone carved into images and
Using this, they are producing what we today
call ‘Digital Signature’
Process of transforming information
Using cipher (algorithm)
Unreadable to everyone except the one having
METHODS OF ENCRYPTION
Consists of two main categories
Stream Encryption: Clear text encrypted
character by character
Block Cipher Encryption: Clear text encrypted
block by block
USES OF ENCRYPTION
Protect information on your computer.
Protect information in transit
USES OF ENCRYPTION … (cont’d)
Confidentiality of medical, personal and
Contrary to what most people think, encryption
is not a new thing
Encryption is being commonly used to facilitate
Encryption is used to protect data at rest and at