**What is Cryptography?**

Cryptography derives its name from the Greek word “Kryptos,” which means “Hidden Secrets.” Cryptography is the practice and study of hiding information. It’s the Art or Science of converting a plain intelligible data into unintelligible data and again re-transforming that message into its original form. It provides Confidentiality, Integrity, Accuracy.

**Encryption**

The process of converting plain text into an unintelligible format (cipher text) is called Encryption.

**Decryption**

The process of converting cipher text into a plain text is called Decryption.

**What’s Key?**

In cryptography, a key is a variable value that is applied using an algorithm to a string or block of unencrypted text to produce encrypted text, or to decrypt encrypted text. The length of the key is a factor in considering how difficult it will be to decrypt the text in a given message.

**What is a Block Cipher?**

A method of encrypting/decrypting data. Key is used for encryption/decryption. Same size of I/P and O/P

**What is Initialization Vector?**

An initialization vector (IV) is an arbitrary number that can be used along with a secret key for data encryption.

It is a group of hex values.

**Types of Cryptography**

1. Symmetric Key Cryptography (Secret Key Cryptography)

2. Asymmetric Key Cryptography (Public Key Cryptography)

3. HASH FUNCTION

**1. Symmetric Key Cryptography (Secret Key Cryptography)**

a). The Same Key is used by both parties

b). Simpler and Faster

**2. Asymmetric Key Cryptography (Public Key Cryptography)**

a). Two different keys are used Users get the Key from a Certificate Authority.

b). Authentication in asymmetric cryptography is more secured but the process is relatively more complex as the certificate has to be obtained from the certification authority.

**3. HASH FUNCTION**

a). Uses mathematical transformation to irreversibly encrypt information.

b). It is a one-way encryption

c). Uses no key for encryption and decryption.