Relatively speaking:
Roman generals encrypted their communications by pushing the letters back three digits. For example, replace a with d, replace b with e, and so on. This single-letter encryption method was not cracked by Arab scholars until the ninth century through continuous analysis.
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Guide: Everyone is asking this question: Can you keep your password? For 2500 years, rulers, secret agencies and cryptographers have been looking for answers.
Encryption technology has always been used in the political field. Now, everyone uses encryption algorithms when surfing the Internet, sending and receiving emails or using online banking. Encryption can avoid "eavesdropping" events. If there were no encryption algorithms, the Internet might not be what it is today.
The principle of modern data encryption algorithm is still based on the encryption method used by Caesar of the Roman Empire when he contacted his generals, and its principle is based on the alphabet of Caesar's era. Roman generals encrypted their communications by pushing the letters back three digits. For example, replace a with d, replace b with e, and so on. This single-letter encryption method was not cracked by Arab scholars until the ninth century through continuous analysis. But the multi-letter sequential encryption of Blaise de Vigenère, a Frenchman, is not so easy to crack. The backward rank of each letter in this algorithm is different. If D replaces A, it is not necessarily E instead of B. The famous Enigma automatic encryption machine in World War II also works on this principle.
The arrival of the computer age has changed all this. With the increasing processing power, the algorithm becomes more and more complex, and the "attack" becomes more and more efficient. Since then, cryptographers have followed the Kerckhoffs principle, and a cryptographic system should be secure, even if everything in the system except the key can be used as public knowledge. The advantage of this "open source" concept is that anyone can test the advantages and disadvantages of this encryption algorithm.
Attacks aimed at scientific research are desirable. If the attack is successful, a better algorithm will come into play. In 1998, this is the fate of Data Encryption Standard (DES), which was once the preferred encryption method of American authorities. The length of the key is only 56 bits, which can be quickly cracked if brute force attacks are used.
The successor of DES won the competition, and Rijndael algorithm won the final victory. The National Institute of Standards and Technology (NIST) chose Rijndael as the encryption algorithm of American government encryption standard (AES). The algorithm uses 128-bit key, which is suitable for WLAN and blue light encryption. However, this classical symmetry algorithm is not secure enough for network communication. The sender and the receiver use the same key for encryption and decryption. Anyone can intercept the key because it is not encrypted.
The asymmetric encryption method invented in 1970s helps to solve this problem. The receiver generates a public key and a private key, and he sends the public key to those who need to send him encrypted information. A public key can encrypt files, but these files need a private key to decode. The disadvantage of this algorithm is that the key pair needs two groups of large original numbers to generate, which is very time-consuming. For personal business such as online banking, the combination of symmetric method and asymmetric method is effective. The information part is encrypted symmetrically, but the key is encrypted asymmetrically.
When the quantum computer has enough ability to crack the key of 128 bit by brute force attack, the asymmetric encryption method is unsafe. Quantum cryptography uses the principle of physics to protect information, takes quantum as the information carrier, transmits it through quantum channel, and establishes the key shared by legitimate users. Its security is guaranteed by Heisenberg uncertainty principle and single quantum unrepeatable theorem.
Encryption history
400v.Chr. Skytale (gobbledygook)
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Skytale is a stick or scepter with a certain thickness, which is used for encryption. Spartans wrapped important information in leather or parchment on Skytale, and then untied the leather or parchment, which effectively disrupted the alphabetical order. Only when the leather (paper) tape is rolled back to the stick with the same thickness as the original encrypted Arabian Nights, and then the text information on the surface of the stick is juxtaposed, can the original intention be restored.
50 v.chr.caesar password
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The rulers of Rome pushed the letters back three places for encryption, which is now widely known as single-letter encryption.
1360 Alphabetum Kaldeorum
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Rudolph IV of Austria invented the most popular encryption method in the Middle Ages, and he even used it on tombstones.
1467 encrypted disk
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This tool simplifies the letter replacement of single-letter encryption.
1585 dimensional Genard password (Wigenyel)
Blaise de Vigenère, a French diplomat, invented a method to encrypt different letters in the same message with different passwords. This multi-letter encryption method cannot be cracked within 300 years after its birth.
Charles Babbage 1854
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The inventor of the computer, it is said that he was the first to crack the code of D-Genard, and people found this cracking method when looking at his relics.
188 1 kirchhoff principle
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After that, the security of the encryption algorithm no longer depends on the confidentiality of the algorithm, but on the confidentiality of the key.
19 18 password and one-time key
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Enigma is a famous encryption machine in Germany, which generates a replacement rank for each letter. For a long time, it was considered unbreakable.
One-time keys are mathematically secure: using an encoding manual and using different encryption methods for each text-this tool was often used by spies during the Cold War.
1940 tuning bomb
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This machine was invented by Allen Turkin to crack Enigma encryption machine. It contains many cooperative Enigma devices.
1965 Fialka
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The mystery of eastern Europe was used until the fall of the Berlin Wall. Since 1967, it is no longer considered safe.
1973 public key
Three officials from a British think tank first developed asymmetric encryption. It was not revealed until 1997.
1976 DES
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IBM cooperated with NASA to develop data encryption standards for American officials. However, critics found the defect of this algorithm, which reduced the key length from 128 bits to 56 bits.
1977 RSA
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Rivest, Shamir and Adelman invented a reliable asymmetric encryption method. At present, it is mainly used for email encryption and digital signature.
1998 deep fracture
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The Electronic Border Foundation has a computer with 1800 processor, which cracked the DES encryption method by violence.
2000 AES
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Rijndael algorithm, the successor of DES, won the open competition. Advanced encryption standard is the most widely used symmetric encryption method.
2008 Quantum Cryptographic Network DES
The optical fiber network protected by quantum cryptography was first demonstrated in Vienna.
The Future Trend in 2030: Quantum Computer
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