# Cryptography: The math that makes instant messaging secure Science & Tech

But instead of using keys, it relies on algorithms to turn any data input into a fixed-length string of characters. Cryptography was initially only concerned with providing secrecy for written messages, especially in times of war. Because of this broadened interpretation of cryptography, the field of cryptanalysis has also been enlarged. Cryptanalysis (from the Greek kryptós and analýein, “to loosen” or “to untie”) is the science (and art) of recovering or forging cryptographically secured information without knowledge of the key.

The second method is Asymmetric Encryption Cryptography, which uses two different keys —public and private—to encrypt and decrypt data. The public key can be disseminated openly, like the address of the fund receiver, while the private key is known only to the owner. In this method, a person can encrypt a message using the receiver’s public key, but it can be decrypted only by the receiver’s private key. Some of the tools that were developed as a part of cryptography have found important use in cryptocurrency.

The first of these uses is the obvious one—you can keep data secret by encrypting it. The others take a bit of explanation, which we’ll get into as we describe the different types of cryptography. Encryption uses a cipher to encrypt and transform the plaintext into ciphertext. On the other hand, decryption transforms the ciphertext into plaintext by employing the same cipher.

Cryptography is technique of securing information and communications through use of codes so that only those person for whom the information is intended can understand it and process it. In Cryptography the techniques which are use to protect information are obtained from mathematical concepts and a set of rule based calculations known as algorithms to convert messages in ways that make it hard to decode it. These algorithms are used for cryptographic key generation, digital signing, verification to protect data privacy, web browsing on internet and to protect confidential https://www.xcritical.in/blog/what-is-cryptography-and-how-does-it-work/ transactions such as credit card and debit card transactions. The system used by WhatsApp is symmetric; that is, it uses the same key to encrypt and decrypt messages (in contrast, asymmetric systems use different encryption and decryption keys). Symmetric systems require less computing resources and are easier to use, but with them it is essential to guarantee the security of the common key shared by two people. This key is generated by exchanging information over a public channel, using the method introduced by Whitfield Diffie and Martin Hellman in 1976.

• In a passive attack, the intruder can only see the private data but can hardly make any changes to it or alter it.
• On the other hand, decryption transforms the ciphertext into plaintext by employing the same cipher.
• Cryptography ensures confidentiality by encrypting sent messages using an algorithm with a key only known to the sender and recipient.
• In computer science, cryptography refers to secure information and communication techniques derived from mathematical concepts and a set of rule-based calculations called algorithms, to transform messages in ways that are hard to decipher.
• Hash functions ensure that data integrity is maintained in the encryption and decryption phases of cryptography.
• An early substitution cipher was the Caesar cipher, in which each letter in the plaintext was replaced by a letter some fixed number of positions further down the alphabet.

Cryptography is a necessary form of cybersecurity that uses encryption methods to keep digital data and communications secure and out of the hands of potential threats or bad actors. Data protection is highly important in this digital era where so much information is stored on computers, in the cloud, and on the internet. Data security is important to businesses, industries, companies, and individuals alike. Cryptography is a form of securing digital data and messages often using special keys that only the sender and recipient have access to. Cryptography uses mathematical systems and algorithms to encrypt and decrypt data.

Cryptanalysis is the term used for the study of methods for obtaining the meaning of encrypted information without access to the key normally required to do so; i.e., it is the study of how to “crack” encryption algorithms or their implementations. Cryptography has been the subject of intense standardization efforts resulting in a range of International Standards that encapsulate the knowledge and best practice of leading experts in the field. Internationally agreed ways of working make technology more secure and interoperable. By using cryptography standards, developers can rely on common definitions, as well as proven methods and techniques. Both DES (Data Encryption Standard) and AES (Advanced Encryption Standard) are popular examples of symmetric-key algorithms, while prominent asymmetric-key algorithms include RSA (Rivest-Shamir-Adleman) and ECC (elliptic curve cryptography).

## What are cryptographic algorithms?

There is also active research examining the relationship between cryptographic problems and quantum physics. Cryptanalysis of the new mechanical ciphering devices proved to be both difficult and laborious. In the United Kingdom, cryptanalytic efforts at Bletchley Park during WWII spurred the development of more efficient means for carrying out repetitious tasks, such as military code breaking (decryption). This culminated in the development of the Colossus, the world’s first fully electronic, digital, programmable computer, which assisted in the decryption of ciphers generated by the German Army’s Lorenz SZ40/42 machine. The first known use of a modern cipher was by Julius Caesar (100 B.C. to 44 B.C.), who did not trust his messengers when communicating with his governors and officers.

These algorithms generate cryptographic keys, create digital signatures, safeguard data privacy, enable online browsing on the Internet, and ensure the confidentiality of private transactions like credit and debit card payments. Cryptography algorithms are the means of altering data from a readable form to a protected form and back to the readable form. Cryptographic algorithms are used for important tasks such as data encryption, authentication, and digital signatures. Public-key algorithms are based on the computational difficulty of various problems.

However, it’s asymmetric cryptography that usually deals with these processes. Cryptosystems encrypt and decrypt information using cryptographic algorithms, or ciphers, to secure communications between computer systems, devices, and applications. Symmetric-key cryptographic algorithms use the same cryptographic keys for both the encryption of the plaintext and the decryption of the ciphertext. Symmetric encryption requires that all intended message recipients have access to a shared key.

### Encryption and Decryption

With this encryption/decryption protocol being used, an eavesdropper gains no knowledge about the actual (concealed) instruction A has sent to B as a result of listening to their telephone communication. Such a cryptosystem is defined as “perfect.” The key in this simple example is the knowledge (shared by A and B) of whether A is saying what he wishes B to do or the opposite. Encryption is the act by A of either saying what he wants done or not as determined by the key, while decryption is the interpretation by B of what A actually meant, not necessarily of what he said. Storing keys properly is essential, and appropriate key protection requires additional encryption.

Now that we understand what cryptography is, let us learn how cryptography aids in the security of messages. The 2016 FBI–Apple encryption dispute concerns the ability of courts in the United States to compel manufacturers’ assistance in unlocking cell phones whose contents are cryptographically protected. In recent times, cryptography has turned into a battleground of some of the world’s best mathematicians and computer scientists. https://www.xcritical.in/ The ability to securely store and transfer sensitive information has proved a critical factor in success in war and business. Cryptography is an important computer security tool that deals with techniques to store and transmit information in ways that prevent unauthorized access or interference. Another potential solution is cryptography quantum, whereby it is impossible to copy data encoded in a quantum state.

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For this reason, public-key cryptosystems based on elliptic curves have become popular since their invention in the mid-1990s. Just as the development of digital computers and electronics helped in cryptanalysis, it made possible much more complex ciphers. Furthermore, computers allowed for the encryption of any kind of data representable in any binary format, unlike classical ciphers which only encrypted written language texts; this was new and significant. Computer use has thus supplanted linguistic cryptography, both for cipher design and cryptanalysis. Many computer ciphers can be characterized by their operation on binary bit sequences (sometimes in groups or blocks), unlike classical and mechanical schemes, which generally manipulate traditional characters (i.e., letters and digits) directly.

However, since message integrity is almost always a valuable assurance, it is frequently integrated into symmetric encryption algorithms like AES-GCM. This combination of public-key cryptography for key exchange and symmetric encryption for bulk data encryption is known as hybrid encryption. An encryption scheme is called asymmetric if it uses one key—the public key—to encrypt data, and a different but mathematically related key—the private key—to decrypt data.