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Cryptography Definition


Derived from “Kryptos”, meaning hidden fundamentally, Cryptography is the procedure of securing information and communications from adversaries employing code. The intention behind it is to make the content readable to only those for whom it’s intended. Nowadays, it is known as a means which provides methods to protect information and communication through mathematical concepts and algorithms.

In the present master control environment, techniques like scrambling plaintext into ciphertext and vice versa are related to cryptography. When a plain text message is codified using any suitable scheme, the resulting message is called Cipher Text and it is readable only by those who know the encoding and decoding process of that particular scheme. This process of conversion is called encryption and decryption respectively. Examples are substitution and transposition techniques. In substitution, replacement of plain text characters by other characters, numbers, or symbols is done. While in transposition, characters of plain text are scrambled amid themselves.

However, earlier cryptography included microdots, merging of words and images, etc. Coming to today’s scenario, cryptography revolves around its four purposes, namely:

  1. Confidentiality - That is, only the authorized can view sensitive or classified information.

  2. Integrity - This protects information from unauthorized alteration.

  3. Non-repudiation – It is the ability to ensure that a party to a contract or a communication cannot deny the genuineness of their signature.

  4. Authentication – It is the process of verifying the identity of the user or information.

Types of Cryptography:

Turning up to the classification, cryptography is principally classified into:

  • Symmetric Key Cryptography: Here, a single common key is used for both encrypting and decrypting the messages by the sender and receiver. This system is faster, simpler just both sender and receiver need to exchange keys securely. It is also known as secret-key cryptography. The most popular symmetric-key cryptography system is Data Encryption Standards (DES).

  • Hash Functions: Here, none of any key is used. Also, hash functions are frequently used by operating systems for password encryption. Example SHA-1, SHA-2, and SHA-3.

  • Asymmetric Key Cryptography: Finally here, instead of a single key unlike symmetric, a pair of keys is used to encrypt and decrypt messages. They are public key and private key, also both are different. Widely used public-key cryptography includes RSA (Rivest–Shamir–Adleman), Elliptic Curve Digital Signature Algorithm (ECDSA), and Digital Signature Algorithm (DSA).

Apart from the above algorithms, symmetric is further classified into classical, transposition, substitution, and modern, stream, block ciphers, etc.

Now, securing the information through the key is alright, but placing these keys appropriately through edges is important. This can be achieved either by storing these keys in a file system and protecting them with access control lists (ACLs) or by encrypting keys with a second key

encrypting key (KEK). Otherwise, they can also be secured by, making use of a hardware security module (HSM).

Lastly, from being initiated by Julius Caesar in 100 B.C. for encrypting messages for the governors, to securing the information and communication, utilizing various algorithms today cryptography has been proved as one of the assuring techniques for reliable exchange of messages. Apart from few limitations, cryptography had helped exercise the practice of digital certificates and digital timestamps. Even it plays a crucial role in the triumph of wars and trades. Just always make it certain to use algorithms, key strengths, and modes of operation that kowtow to industry best practices.

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