Introduction to Cryptography Basic Principles

When we come the period cryptography, the main object and possibly the only thing that comes

to our mind is private communication during encryption. There is more to cryptography that just

encryption. In this article, we will effort to study the fundamentals of cryptography.

The basic principles

1. Encryption

A simplest form, encryption is to change the data in some illegible form. This helps incasing the

division the isolation while sending the data from sender to receiver. On the receiver side, the

called as decrypted and can be bring back to its creative form. the reserve of encryption is called

as decryption. The concept of encryption and decryption require some further in sequence is

called as decryption. The concept of encryption and decryption requires some extra information

for encrypting and decrypting the data. the information is known as key. there may be cases

when same key can be used for both encryption and decryption while in positive cases,

encryption and decryption while in positive cases, encryption and decryption may require

different keys.

2. Authentication

This is a new important principle of cryptography. In a layman`s term, verification ensures that

the message was originate from the creator claim in the message.now, one may think how to

make it probable? Assume Alice seds a message to bob and now bob needs verification that the

message has been indeed sent by Alice. This can be made probable if Alice performs some

action on message that bob knows only Alice can do. This forms the basic original of

confirmation

3. Integrity

Now, difficulty that a message system can face is the loss of honesty of messages being sent from sender to reciver.this means the cryptography should ensure that the messages that are received by the receiver are not altered anywhere on the communication path. this can be achieved by using the concept of cryptographic hash.

4. Non Repudiation

If Alice sends a message to bob but denies that the she has actually sent the message? it`s like

these may happen and cryptography should prevent the originator or sender to act this way. one

popular way to achieve this is through the use of digital signatures.

Types of Cryptography

Cryptography is three types of cryptography techniques:

Privacy key Cryptography

Public key cryptography

Hash Functions

Secret Key Cryptography

Cryptography technique used by a single key. Senders apply a key to encrypt a message as the receiver applies same key to decrypt the message. since it`s single key is used to in this a symmetric encryption.

This technique is the biggest problem. it is the distribution of key as this algorithm makes use of single key for encryption or decryption.

.2. Public Key Cryptography

Cryptography technique involves two key crypto system in which a secure communication it can

be take between sender and receiver over insecure communication channel. the pair of key is

applies here so this technique is also known as asymmetric encryption.

In this technique, each party has a public key and private key and private key private is secret

and Is not exposed while the public key is shared all those whom you want to communicate with.

if alice wants to a message send to bob, then alice will encrypt it with Bob`s public key and bob

can decrypt the message with its private key.

This is what we use as we group public key verification in open ssh to login from one server to

anther server in the backend without have to enter the key.

3. Hash Functions

Any key involve does not any technique. It uses a fixed size & hash value that is compute on the

basis of the plain text message. The hash functions are used to check the integrity of the message

to guarantee that the message has not be changed, compromise or artificial by virus.

So we see that how different types of cryptography techniques (described above) are used to

implement the basic principles that we discussed earlier. In the future article of this series, we’ll

cover more advanced topics on Cryptography.