Public Key Cryptography is a cryptographic technique that involves 'two distinct keys' for encryption and decryption. That's why it is also known as asymmetric-key cryptography. The public key cryptography is totally based on the 'invertible mathematical' function which makes it different from the conventional symmetric key cryptography. It is not that symmetric key … [Read more...] about Public Key Cryptography

# Security

## RSA Algorithm in Cryptography

RSA is a first successful public key cryptographic algorithm. It is also known as an asymmetric cryptographic algorithm because two different keys are used for encryption and decryption. RSA is named after Rivest, Shamir and Adleman the three inventors of RSA algorithm. The algorithm was introduced in the year 1978. In this section, we will discuss, RSA algorithm along with … [Read more...] about RSA Algorithm in Cryptography

## Fundamental Security Design Principles

The security design principles are considered while designing any security mechanism for a system. These principles are review to develop a secure system which prevents the security flaws and also prevents unwanted access to the system. Below is the list of fundamental security design principles provided by the National Centres of Academic Excellence in Information … [Read more...] about Fundamental Security Design Principles

## Network Security Model

A Network Security Model exhibits how the security service has been designed over the network to prevent the opponent from causing a threat to the confidentiality or authenticity of the information that is being transmitted through the network. In this section, we will be discussing the general ‘network security model’ where we will study how messages are shared between the … [Read more...] about Network Security Model

## Advanced Encryption Standard (AES)

Advanced Encryption Standard (AES) was introduced by NIST in 2001 is a symmetric block cipher which overcomes the key size weakness of DES. AES comes with the variable key sizes i.e. 128-bit key, 192-bit key and a 256-bit key. AES does not follow the Feistel structure in fact it operates on entire plaintext block at once instead of dividing them into two halves. AES can be … [Read more...] about Advanced Encryption Standard (AES)

## Feistel Block Cipher

Feistel block cipher is a structure used to derive many symmetric block ciphers such as DES which we have discussed in our previous content. Feistel cipher proposed a structure which implements substitution and permutation alternately to obtain cipher text from the pain text and vice-versa. In the Feistel block cipher, each block has to undergo many rounds where each round … [Read more...] about Feistel Block Cipher

## Block Cipher

Block cipher is an encryption and decryption method which operates on the blocks of plain text, instead of operating on each bit of plain text separately. Each block is of equal size and has fixed no of bits. The generated ciphertext has blocks equal to the number of blocks in plaintext and also has the same number of bits in each block as of plain text. Block cipher uses the … [Read more...] about Block Cipher

## Data Encryption Standard (DES)

Data Encryption Standard (DES) is the symmetric block cipher which encrypts a 64-bit plain text in a 64-bit ciphertext. The DES was introduced by the National Institute of Standard and Technology (NIST) in the 1970s. Initially, DES was only used in financial applications but later it was accepted as the cryptographic algorithm by other organizations too. Being a symmetric … [Read more...] about Data Encryption Standard (DES)

## Transposition Technique in Cryptography

Transposition technique is an encryption method which is achieved by performing permutation over the plain text. Mapping plain text into cipher text using transposition technique is called transposition cipher. In this section, we will discuss variations of transposition technique, and we will also observe how the transposition technique is different from the substitution … [Read more...] about Transposition Technique in Cryptography

## Substitution Technique in Cryptography

Substitution technique is a classical encryption technique where the characters present in the original message are replaced by the other characters or numbers or by symbols. If the plain text (original message) is considered as the string of bits, then the substitution technique would replace bit pattern of plain text with the bit pattern of cipher text. We will discuss … [Read more...] about Substitution Technique in Cryptography