History of Cryptography
The RAS encryption method is currently the most widely used algorithm, such as our mobile phone payment encryption, online banking encryption, and digital signatures will use the RSA encryption algorithm. The three letters RSA represent its three founders, Ron Rivest, Adi Shamir, and Leonard Adleman.
Before analyzing the RSA encryption method, let's first understand the development history of cryptography.
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First Generation Encryption: Stealth
The concealment method, as the name implies, is to hide information. It has been used since the appearance of text. The cracking method is to search carefully, which is purely physical work. The historical record of the first encryption method comes from ancient Greek historiography and a story recorded by Herodotus. At that time, the powerful Persian Empire attacked Greece. After the old king of Sparta learned about it, he wrote the news on a wooden board, and then coated it with a layer of wax. After the recipient received the secret, he began to prepare for war. Therefore, in 480 AD, Persia was defeated.
This secret report saved Athens and Sparta, that is, modern civilization. (Modern civilization has two ideological roots, one is ancient Greek thought and the other is later Christian thought.) -
Second Generation Encryption: Shift and Substitution (Caesar Cipher)
The method of shifting and substitution is relatively simple, it appeared about 5,000 years ago, but it was not cracked by the frequency analysis method invented by the Arabs until the 9th century, with an interval of more than 4,000 years. (Probability begins to appear in cryptography, applications of mathematics begin.)
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Third Generation Encryption: Virginia Cipher
Starting from this generation of encryption, the concept of "key" began to appear, and the iteration speed of encryption and decryption began to accelerate, because mathematics began to be applied in the field of cryptography.
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The fourth generation of encryption method: Enigma (Enigma)
The Enigma machine is a machine invented after World War I and later cracked by Turing.
From the first generation to the fourth generation of encryption, the classical era of cryptography has come to an end.
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The Fifth Generation Encryption Method: Demon King Encryption System
Although the devil's encryption method is difficult to break, there are loopholes in the key transmission process. Because of the emergence of computers, the smallest unit of encryption has changed from letters to numbers, and the changes in numbers have disrupted the underlying structure of information. The binary 0 and 1 make the complexity of the password increase by an unknown number of orders of magnitude.
Therefore, cryptography before the advent of computers is called classical cryptography, and that after that is called modern cryptography.
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Sixth Generation Encryption: RSA Encryption System
The RSA encryption system solves the problem of loopholes in key delivery, and the reliability is greatly improved. Although it is not impossible to crack, but because of the large amount of calculation, the theoretical cracking time is infinitely long. If a quantum computer appears, the computing power of the computer will be greatly improved, and the infinitely long cracking time may be shortened to a few minutes to a few hours. Prior to this, the RSA encryption algorithm can be counted as having no cracking method.
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Seventh Generation Encryption Algorithm: Quantum Encryption
The theoretical support behind quantum encryption comes from the uncertainty principle and special algorithms (don't understand...)
The relevant knowledge in this article comes from the course "Zhuo Ke's Cryptography Class", please indicate the source for reprinting.