It is the study and practice of secure communication against the third party attackers. Cryptography is used to inventing and analyzing protocols that stopped third parties from accessing the transmitted messages. It is fulfilling the below functions.

  1. Confidentiality – The information in the message can access only to people who are authorized to access it.
  2. Integrity – This is guarantee the message has been not modified during the transmission.
  3. Authentication – that the identities of all parties are assured.
  4. Non-Repudiation – that neither the sender nor receiver can deny communication

Modern cryptography is used to,

  • Electrical  engineering purposes
  • Chips based payment cards
  • Communication science
  • Mathematics and computer science
  • Military services

Mathematically theory practices and computer science are used to modern cryptography. Computational strong assumptions are used to design cryptographic algorithms. It is very difficult to break that kind of algorithm by any adversary. It is theoretically possible to crack such a system, but it is not possible to do so by any known practical means. These schemes are therefore termed theoretical advance, computationally secure. An application of cryptography includes chip-based payment cards, e-commerce, and digital currencies.

Cryptography | Encryption | Decryption | Symmetric | Asymmetric


When using plain text or clear text, it is possible to read and understand the data contained in it. It can be disclosed for unintended receivers when data transmit in the unsecured networks. The method of underlining the plain text in such a way if hide its substance is called encryption. The ciphertext is called as encrypting plain text results in an unreadable format. Encryption is used to ensure the information is hidden to the third party and that is not read even though the third party sees the encrypted data.


Decryption is the vise-worse process of encryption of data. That means converting the cipher text to plain text. A cipher has two types of algorithms one is creating the decryption and the other one is used to reverse the decryption. The key and algorithm are controlled the cipher. The key is a secret phrase that is known only for communication. This will be used to decrypt the ciphertext.

The modern field of cryptography can be divided into several areas of study,

  1. Private Key Encryption (Symmetric-key cryptography)
  2. Public Key Encryption (Asymmetric-key cryptography)

After considering the advantages and disadvantages of symmetric-key and asymmetric-key cryptosystem the hybrid cryptosystem has been introduced, it is a combination of symmetric-key and asymmetric-key. Hybrid cryptosystem most useful for e-commerce applications because it is secure and fast. It used a highly secure type of asymmetric key mix with the effectiveness of symmetric key encryption. The hybrid system used a unique session key along with symmetrical key encryption. It is used as an asymmetric-key mechanism to exchange the key and symmetric-key mechanism to encrypt the data.

After establishing the connection channel between users they can start to communicate through a hybrid cryptosystem. The public key technology cause slows down the process but working both together encryption is enhanced.