Cryptography

 

Cryptography is a way of safeguarding information 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, internet web surfing, and secret communications such as credit card transactions and email.

Techniques of cryptography

Cryptography is inextricably linked to the fields of cryptology and cryptanalysis. It covers techniques such as microdots, combining words and pictures, and other methods for concealing data in storage or transport. However, in today's computer-centric world, cryptography is most commonly linked with scrambling plaintext (regular text, also known as cleartext) into ciphertext (a process known as encryption), then back again (known as decryption). Cryptographers are professionals who work in this sector. 

Modern cryptography is concerned with the four goals listed below:

1. Confidentiality: the information cannot be understood by anybody who was not intended to understand it.
2. Integrity: the information cannot be changed while in storage or transit between the sender and the intended receiver without being discovered.
3. Non-repudiation: The creator/sender of the material cannot subsequently dispute his or her intentions in creating or transmitting the information.
4. Authentication: The transmitter and receiver can verify each other's identities as well as the origin/destination of the information.

Cryptosystems are procedures and protocols that fulfil some or all of the aforementioned requirements. Cryptosystems are sometimes considered to simply apply to mathematical methods and computer programmes; nevertheless, they also involve the regulation of human behaviour, such as selecting difficult-to-guess passwords, turning off unneeded systems, and not discussing sensitive operations with outsiders. 

History of cryptography

The term "cryptography" is derived from the Greek word kryptos, which means "hidden." The origins of cryptography are typically attributed to the Egyptian usage of hieroglyphics about 2000 B.C. These were made up of intricate pictograms, the entire meaning of which was only known to a select few. Julius Caesar (100 B.C. to 44 B.C.) was the first known user of a modern cypher, who did not trust his couriers while dealing with his governors and commanders. As a result, he devised a method in which each character in his communications was substituted with a character three positions higher in the Roman alphabet. 

Cryptography has recently become a battleground for some of the world's greatest mathematicians and computer scientists. The capacity to securely store and transport sensitive information has proven to be a crucial component in both military and commercial success.

Because governments do not want certain entities in and out of their countries to have access to methods of receiving and sending hidden information that may be a threat to national interests, cryptography has been subject to a variety of restrictions in many countries, ranging from limitations on the use and export of software to the public dissemination of mathematical concepts that could be used to develop cryptosystems.

However, the internet has enabled the dissemination of powerful programmes and, more crucially, the underlying cryptographic techniques, such that many of the most advanced cryptosystems and concepts are now available to the public.