Cryptography is the practice and study of techniques for secure communication in the presence of third parties. It is also used to set up a secure connection between two systems. Cryptography uses mathematics (primarily arithmetic and number theory) to provide confidentiality, integrity, and authenticity for messages under certain conditions. It includes confidentiality by ensuring that information cannot be read or tampered with in transit, where unauthorized parties could intercept and read. 

The first thing to know about cryptography is that there is no single universal method for encrypting your message. There are many ways to do it, each with its advantages and disadvantages. Today's most common encryption methods are public and symmetric key cryptography.

Many cryptographic algorithms arise naturally out of their use in other contexts, such as digital signature schemes or encryption techniques for secure electronic commerce over insecure networks such as the Internet. For example, RSA cryptosystems were initially developed to solve integer factorization.

Cryptography is sometimes used by criminals to avoid detection and allow illicit messages to be passed along without interception. It is also used by public-key cryptosystems such as RSA, which are widely used in security protocols. 

Encryption Algorithms

A cryptography algorithm is a method of encryption and decryption that uses a mathematical formula to convert plain text into cipher text and back again. The cryptography encryption algorithm is a type of cipher used for data confidentiality and integrity in a computer system. It uses an encryption key to convert plaintext into ciphertext, which is then sent over a network, such as the Internet, to a destination where the receiver will decrypt it. 

Cryptography encryption algorithms are commonly used in commercial electronic commerce, online banking, and other applications where confidentiality is essential. These encryption algorithms include Data Encryption Standard (DES), Triple DES, Blowfish, and CAST-256.

There are several types of encryption algorithms; these include block ciphers and stream ciphers.

  • A block cipher encrypts blocks of plaintext and decrypts them one at a time. 
  • A stream cipher encodes multiple characters or characters from a file in a single operation.

How do Various Cryptographic Algorithms Work?

Cryptographic algorithms have a basic algorithm that produces a key, and then they each use this key to encrypt and decrypt information. But there are many ways to go about it.

  • One way is to use a block cipher, which takes several bytes and converts them into a more extended sequence of bytes. This process is called encryption. 
  • The other way is to take a block cipher, convert it into something smaller, and then convert it back into the original block size. This process is called decryption (or deciphering).

These algorithms can be symmetric or asymmetric, depending on the algorithm used. 

  • Symmetric algorithms use the same key to encrypt and decrypt the data, while asymmetric algorithms use two separate keys, one to encrypt and one to interpret the data.
  • The algorithms also use a message authentication code (MAC) to ensure the message's integrity.

Overview of Cryptography Techniques

The study of cryptography has been active since the invention of electronic digital communications. Today, cryptography has become indispensable in almost all areas of life. From banking and government to transportation, telecommunications, and even shopping malls, cryptography helps keep our data secure against spying and hacking.

The basic idea behind cryptography is to use an encryption key to encrypt information so that only those who have access to it can read it. All other people will see random letters instead of the original message. To decrypt a message, all you need is the correct key.

Cryptography is not limited to computer science or mathematics; it involves mathematics from other fields, such as economics, statistics, and physics. It also requires engineering because most cryptographic algorithms are based on mathematical principles such as linear algebra (matrixes) and number theory (arithmetic).

Cryptography and its Types

Cryptography is the practice and study of techniques for securing communications, information, and data in an unreadable format for unauthorized users. It protects information and communications through codes so only those for whom the information is intended can read and process it.

There are three main types of cryptography: symmetric key encryption, asymmetric key encryption, and public-key encryption.

Symmetric key encryption: This type of encryption uses the same key to encrypt and decrypt messages. The keys used in this type of encryption must be kept secret by both parties, making them vulnerable to attack by hackers. Symmetric keys are most commonly used for public key systems.

Asymmetric key encryption: This type of encryption uses two keys instead of one. One key is used for encryption, and another key is used for decryption. These keys do not have to be kept secret because they are only used once per message and can be reused multiple times. Asymmetric keys are most commonly used in public-key systems.

Public-key encryption: Public-key systems use a pair of mathematically related keys that cannot be derived from each other without knowing the different keys (a process known as factoring). This means that even if someone finds your private key, they will only be able to derive your public key (and vice versa).

Techniques Used For Cryptography

The most commonly used techniques in cryptography, are,

History of Cryptography

The history of cryptography is long and complex, spanning centuries and continents. Cryptographic techniques have been used for millennia by various cultures and civilizations, from the ancient Egyptians to the ancient Greeks to the ancient Chinese.

  • The earliest known use of cryptography dates back to the Old Kingdom (c. 2679 - c. 2181 BCE), where scribes used it to conceal specific messages. The earliest recorded example of cryptography came during the Han Dynasty (206 BCE - 220 CE) when Chinese government officials used it to encrypt documents.
  • One of the most famous cryptographic systems ever devised is the Caesar cipher, invented by Julius Caesar in 44 BCE for personal use. It's still widely used today to protect sensitive information by hiding it within seemingly harmless text.
  • In the 4th century BC, the Greek historian Herodotus wrote of an encryption device used by the Spartans to communicate military secrets. 

From there, cryptography has played an essential role in every significant technological development, including:

  • Chipped-Stone Technology
  • Invention of Paper Money
  • Creation of Printing Presses
  • Vision of Guns (Firearms)
  • Design of Paper Currency (Paper Money)

Features of Cryptography

Some of the crucial features of cryptography are,

  • Authentication: Authentication is the process of verifying the identity of a person or entity. It ensures that only authorized personnel can access confidential data or personal networks.
  • Confidentiality: Confidentiality is keeping data or information secret from unauthorized individuals or entities. It is used to ensure that the data is only accessible by authorized personnel.
  • Integrity: Integrity ensures that data is not modified, corrupted, or tampered with during transmission or storage.
  • Non-repudiation: Non-repudiation ensures that the sender or receiver cannot deny a transaction or communication at a later date.
  • Authorization: Authorization is the process of allowing authorized personnel access to specific data or networks.
  • Key Management: Key management securely stores, distributes, and manages cryptographic keys.

Types Of Cryptography

The following are the crucial types of cryptography:

  • Symmetric Key Cryptography
  • Asymmetric Key Cryptography
  • Hash Functions
  • Digital Signatures
  • Message Authentication Codes
  • Elliptic Curve Cryptography
  • Quantum Cryptography

Applications Of Cryptography

The following applications are more crucial one,

  • Electronic Commerce: Cryptography is used in e-commerce to protect data from theft and misuse. Digital signatures, encryption, and authentication protocols secure online transactions.
  • Secure Storage: Encryption is used to store data securely on storage devices like external hard drives, USBs, memory cards, etc.
  • Wireless Network Security: Cryptography secures wireless networks from attacks. It is used to authenticate users and encrypts data transmitted over the web.
  • Online Banking: Cryptography is used to secure online banking transactions. It is used to authenticate users, encrypt data, and securely transfer funds.
  • Secure Email: Cryptography is used to send emails securely. It is used to authenticate users, encrypt data, and ensure that emails are transmitted securely.

Advantages and Disadvantages of Cryptography


  • Security: Encryption provides privacy and protection from unauthorized access to data.
  • Authentication: Digital signatures can provide authentication, ensuring the sender is who they say they are.
  • Integrity: Data integrity ensures that the message has not been changed in transit.
  • Digital signatures: Cryptography can also be used to create digital signatures, verifying a sender's identity.


  • Speed: Encryption can slow down during the data transmission, taking longer than unencrypted messages.
  • Require a large amount of power: Cryptography is computationally intensive, requiring large amounts of computing power to encrypt and decrypt data.
  • Vulnerable: It is also susceptible to cryptographic attacks, such as brute-force attacks, that can compromise the security of encrypted data.
  • Requiring a high skill: Cryptography requires a high degree of skill, knowledge, and resources to implement correctly.

Cryptography Concerns

Cryptography is a powerful technique for securing data and communication. However, it has several security concerns that must be addressed.

  • Key Management: Key management securely controls and distributes the cryptographic keys used to encrypt and decrypt data. Poor key management can lead to crucial leakage, which can compromise the security of the data.
  • Attacks: Cryptographic systems are vulnerable to attacks from an adversary. Various episodes, such as brute-force, man-in-the-middle, and side-channel attacks, can try to break the encryption and gain access to sensitive data.
  • Security Protocols: Security protocols are the rules that govern how encryption and decryption work. Weak protocols can lead to inadequate security, so it is vital to use secure protocols.
  • Key Length: The length of the cryptographic keys used to encrypt and decrypt data is essential.

Types of Attacks in Cryptography

  • Brute Force Attack: In a brute force attack, an attacker attempts to gain access to a system or decrypt a message by guessing the correct password or key.
  • Man-in-the-Middle Attack: This attack occurs when an attacker intercepts communication between two parties, allowing them to observe and modify the communication.
  • Dictionary Attack: A dictionary attack uses a list of common words or phrases to guess a user’s password.
  • Replay Attack: In a replay attack, an attacker captures a valid transmission and retransmits it, possibly masquerading as the intended recipient.
  • Birthday Attack: Also known as the birthday paradox, this attack takes advantage of the fact that finding two inputs with the same hash output is more accessible than finding a single input with a specific hash output.

Tried and Tested Cryptographic Methods for Consistent Data Security

  • Symmetric Key Cryptography: This cryptography uses the same key for encryption and decryption. Examples include AES, DES, and Blowfish.
  • Asymmetric Key Cryptography: This type of cryptography uses two keys for encryption and decryption. Examples include RSA and Elliptic Curve Cryptography.
  • Hashing: This type of cryptography uses one-way functions to transform plaintext into a unique and irreversible ciphertext. Examples include SHA-256, SHA-512, and MD5.
  • Digital Signatures: This type of cryptography allows the sender of a message to sign the message with their private key and the recipient to verify the signature with the sender's public key. Examples include RSA and DSA.
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