Cryptography

Communication of information and data between two parties or devices

For technical definition, see Cryptography (disambiguation)

It is primarily concerned with how to protect communications against fraud,though it also tries to prevent an attacker from being aware of the encoder's message, or "man in the middle" attacks from eavesdropping on a message during transmission, for malicious purposes.

Cryptography can be applied universally in computing systems to authenticate users, track user activity, create digital certificates, and store cryptographic keys.

 In computer networks, it enables secure exchange of data between users by providing authentication mechanisms, integrity assurance, confidentiality, and key sharing among others.

 Some cryptographic primitives are widely used for protecting the privacy of individuals and applications.

History 

The name 'cryptography' comes from Latin criptus, meaning lock, which is derived from the Greek word for "cipher".For centuries, many classical cryptographic systems were based on the use of ciphers, but later some began using random number generation as part of their security function instead.

 Another major contribution came in 1944, when Leonard Kleinrock (1904–1955) proved that it is not possible to generate a universal secret key for any purpose of message encryption, regardless of complexity level, given the mathematical properties of ciphers such as number theory and algebra.

This has since become known as the Kleinrock Problem.

In 1969 John Adleman (1928–1991) created what he called the Turing Machine as a tool for demonstrating fundamental concepts of computation.

 He described his work in 1973 in this book "Computational Theory".

 In 1973 he demonstrated how the output is computed, and that its computational efficiency can rival a human brain, but he could not do so because of limitations in available computers at the time. 

 Because there are no direct functions of the recipient's public key, the receiver must produce a private key. Many others came after it, including the RC4 algorithm,

PKCS2:

RC4 – RSA Advanced Encryption Standard (RFC 852)

RC5 – RFC 852 Advanced Cipher Standard (ARC)

PKCS2 – A Diffie-Hellman Message Exchange Algorithm (RFC 5377)

RSA – US National Institute of Standards and Technology (NIST) / IMSI standard

PKCS2 – New Directions for Key Management (NDoK) standard

In 1993 Richard Branson released WPA3 (Version 2), with improvements to AES and RSAC.

 There were several versions of the same software until 2014.By then, most browsers have taken advantage of HTTPS, allowing secure communication between web servers and web browsers.

 However, there were still flaws with insecure protocols such as HTTP 1.1, despite HTTP 1.1 being finally dropped in 2012. HTTP 1.0, which was replaced by TLS 1.3, had flaws too; TLS was eventually dropped in 2017.

Asymmetric cryptography refers to using one party's key (private key) and one party's public key.

 Thus, if you want to read a file encrypted with your own public key, you'd need to know all other secrets such as yours. Asymmetric cryptography, therefore, only requires two parties to be involved, and is more efficient and less vulnerable to cracking attempts. 

 Its weaknesses make it difficult to implement for all systems; while they can solve a variety of tasks in a system, it can't guarantee that the key will remain un-modified; thus, it cannot perform as well as or outperform other solutions such as DES, Triple DES, FIDE, etc.,