# What is Cryptography?

##### Parag

Nowadays, every human action is inextricably linked to computing systems. This computing technology is used in every application in the healthcare, education, finance, software, and marketing industries. However, you may be wondering how companies safeguard their information and how your financial activities are kept private. The solution to all of these questions is “Cryptography.”

Cryptography is a way of data protection and communications by using codes to ensure that only those who are supposed to read and use the information may do so. The prefix “crypt-” denotes “hidden” or “vault,” while the suffix “-graphy” denotes “writing.”

Cryptography is a term used in computer science to describe secure information and communication systems that use mathematical ideas and a series of rule-based calculations known as algorithms to change communications in difficult-to-decipher ways. These deterministic algorithms are used for cryptographic key generation, digital signature, data privacy verification, surfing the web, and private communications such as credit card transactions and email, and other purposes.

Organizations commonly use cryptography to achieve the following goals:

- Reliability
- Confidentiality
- Non-repudiation
- Authenticity

**Cryptography – Meaning:**

More broadly, cryptography is concerned with developing and analyzing protocols that prevent third parties or the general public from reading private messages; modern cryptography emphasizes various aspects of information security such as data confidentiality, data integrity, authentication, and non-repudiation. Modern cryptography occurs at the crossroads of mathematics, computer science, electrical engineering, communication science, and physics.

Prior to the contemporary era, cryptography was virtually synonymous with encryption, transforming information from legible to incomprehensible gibberish.

**Types of Cryptography**

Cryptography may be classified into three types:

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

Secret Key Cryptography, also known as symmetric cryptography, encrypts data with a single key. Because symmetric cryptography uses the same key for both encryption and decryption, it is the simplest kind of cryptography.

The cryptographic method encrypts the data using the key in a cypher, and when the data has to be retrieved again, a person entrusted with the secret key can decode the data. Secret Key Cryptography may be used on both in-transit and at-rest data, although it is most often employed on at-rest data since revealing the secret to the message’s receiver might lead to compromise.

Secret-key or symmetric-key encryption algorithms generate a predetermined number of bits known as a block cypher with a secret key that the creator/sender uses to encrypt data and the receiver uses to decrypt it.

It is written as P = D(K,E( P) )

Where,

K = Encryption and decryption key

P = Plain text

D = Decryption

E§ = Encryption of plain text

Some of the examples of Secret Key Cryptography are as follows:

- AES
- DES
- Caesar Cipher

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

The Public Key to encrypt data, cryptography, also known as asymmetric cryptography, employs the use of two keys. The first key is used for encryption, while the second key is utilized to decode the communication.

One key is kept secret and is known as the “private key,” while the other is released openly and may be used by anybody, therefore the “public key.” The keys’ mathematical relationship is such that the private key cannot be deduced from the public key, while the public key can be deduced from the private key. The private key should not be disseminated and should be kept only by the owner. Any other entity can be granted the public key.

Public-key or asymmetric-key encryption algorithms encrypt information with a public key associated with the creator/sender and decode that information with a private key known only to the originator (unless it is exposed or they want to share it).

It is written as P = D(Kd,E(Ke,P)).

Where,

Ke = Encryption key

Kd = Decryption Key

D = Decryption

E(Ke,P) = Plain text encryption using an encryption key

P = Plain text

Some of the examples of Private Key Cryptography are as follows:

- ECC
- Diffie-Hellman
- DSS

**3**. **Hash Functions:**

Hash functions are one-way, irreversible functions that secure data at the expense of not being able to recover the original message. Hashing is a method of converting a given string into a set length string. A decent hashing algorithm will provide distinct outputs for each input. The only method to crack a hash is to test every conceivable input until you obtain the same hash. A hash can be used to hash data (for example, passwords) and in certificates.

Some of the most well-known hashing algorithms are as follows:

- MD5
- SHA-1
- SHA-2 family which includes SHA-224, SHA-256, SHA-384, and SHA-512
- SHA-3
- Blake 2
- Blake 3
- Whirlpool

**Cryptography – Examples:**

**WhatsApp Encryption:**

End-to-end encryption in WhatsApp is a notable example of cryptographic encryption these days. This functionality is available in WhatsApp via the asymmetry model or through public-key techniques. Only the intended recipient is aware of the real message. After installing WhatsApp, public keys are registered with the server, and messages are sent.

2. **Digital signatures:**

Digital signatures are another real-time application of cryptography. When two clients need to sign paperwork for a commercial transaction. However, if two clients never meet, they may not believe each other. Then, encryption in digital signatures guarantees improved authenticity and security.

3. **Email Encryption/Decryption:**

Email encryption protects the content of emails from anyone outside of the email discussion who wants to access a participant’s information. An email is no longer readable by a human when it is encrypted. Your emails can only be unlocked and encrypted with your private email key.

4. **Authentication of SIM cards:**

The SIM must be authenticated before it may be used to access the network. The operator generates a random number and sends it to the mobile device. This random number, together with the secret key Ki, is fed into the A3 algorithm (it is this Ki that recently has been compromised). The result of this computation is returned to the operator, who compares it to the result of the calculation he performed himself.

5. **Disk Encryption:**

Disk encryption software encrypts your whole hard disc, eliminating the need to worry about leaving any traces of unencrypted data on your disc. PGP may be used to encrypt data as well. In this example, PGP encrypts the file with IDEA using the user’s private key and a password given by the user. To unlock the file, the same password and key are needed.

**What is Cryptography Security?**

As cyber-attacks get more sophisticated, security becomes more important, and cryptography techniques become more significant. These cryptographic methods not only thwart hacking operations but also make it impossible for such activities to arise. Cryptography allows users to save encrypted data, allowing them to avoid the key flaw of hacker circumvention.

Cryptography Security decides whether or not an information system secures data and functions as intended.

Cryptography Security considers the six measures listed below.

- Confidentiality
- Integrity
- Authorization
- Authentication
- Availability
- Non-repudiation

**What are Cryptography Tools?**

1. **Token of Security:**

This token is used to authenticate the user. A security token is meant to be encrypted to execute a secure information exchange.

2. **JCA (Java Cryptography Architecture) and JCE (Java Cryptography Extension):**

These are used to validate the encryption procedure. These Java libraries come with preset activities that must be imported before they can be used.

3. **SignTool.exe:**

This is the most commonly used tool by Microsoft to sign files.

4. **Docker:**

Docker may be used to develop large apps. The information stored in the docker is entirely encrypted.

5. **CertMgr.exe:**

This is the installation file, which has the .exe extension.

6. **Algorithms:**

Cryptosystems encrypt and decode data using a set of methods known as cryptographic algorithms, or cyphers, to protect communications between computer systems, devices such as smartphones, and apps. It involves the creation of public and private keys.

7. **Authentication:**

The encrypted data should be decoded using keys. E encrypted information is only known by the intended user. This employs two types of encryption techniques:

- Symmetric Key Cryptography
- Asymmetric Key Cryptography

**Best Practices**

Users should always encrypt any messages they transmit, preferably using public-key encryption. Encrypting essential or sensitive information — anything from collections of family photographs to corporate data like employee records or accounting histories — is also a smart idea. Look for a security system that incorporates powerful cryptography methods as well as a user-friendly interface. This helps to guarantee that encryption features are used regularly and avoids data loss even if a mobile device, hard drive, or storage media gets into the wrong hands.

### Resources

https://en.wikipedia.org/wiki/Cryptography

https://searchsecurity.techtarget.com/definition/cryptography

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