Block chain in cryptography

Objective: discuss the blockchain cannot do without cryptography. Generally speaking, block chain technology is used to verify and store data, using the distributed node formula algorithm to generate and update data, the use of cryptography to ensure data transmission and access security, the use of intelligent contract composed of automated script code to the programming and operation data of a new distributed computing paradigm and infrastructure using block chain data structure. It is the core block chain according to the time sequence of a linked data structure data blocks to sequentially connected modes, and to ensure the cryptology can not be altered and unforgeable distributed books. We have made a summary, can be found there are four indispensable core technology of block chain, respectively, distributed storage, consensus mechanism, principle of cryptography and intelligent contract. Today we will be mainly from the point of origin of a cryptography chat chat blockchain.

Caesar password []

Cryptography is an ancient discipline, has a long and wonderful history. It is used to protect military and diplomatic communication can be traced back to ancient times, thousands of years ago just the text. For thousands of years, has been moving forward constantly in cryptography. With the rapid development of today’s information era, cryptography is becoming more and more important role. It is not limited to use in the military, political and diplomatic aspects, and is more closely related to people’s lives, as people in the online shopping and business exchanges, the use of credit cards and so on, all the knowledge of cryptography to protect people’s personal information and privacy, of course, for we focus on block chain technology, cryptography as the foundation of existence.

Kaiser (Caesar) is the first to replace the password used for military purposes, and record the people. In his book he praises the “Gaul” valiant record, Kaiser described his message was sent to it under siege, on the verge of the surrender of the hands of Cicero. Kaiser love using ciphertext very, the later “Kaiser biography” recorded in Kaiser’s use of a ciphertext. This encryption method, even used today.

Kaiser said the password method is: for each letter, after the letters of the alphabet instead of three. It is a kind of substitution encryption technology, all the letters in the plaintext alphabet (backward or forward) offset according to a fixed number after replaced ciphertext. Example, when the offset is 3 of the time, all the letters will be replaced by A D, B into E, and so on. Is the letter A is replaced by the letter D, replaced by the letter E letter B. For example, Abroad, Kaiser in the ciphertext letter, was replaced by Deurdg. We get that the enemy cannot read the ciphertext.

If there is such an instruction:

RETURN TO ROME

With Caesar password encryption becomes:

UHWXUQ WR URPH

If the instruction is intercepted, will not leak, because literally no meaning.

Now it seems this encryption may be a little naive, but as the history of the earliest written records of the case by using the encryption key: the sender and recipient shared encryption key, marks the beginning of modern cryptography. It can be said that from the Kaiser password, to the thousands of years before the twentieth Century public key cryptography was invented, the principle is the same. Bitcoin blockchain and encryption method, with the principle of difference between Kaiser password, also is the public key. Until today, we see a lot of spy film you will find a lot of agents and spies or take this way of information transmission.

There are a few terms, in particular. Cryptographers usually speak to write the original information of the alphabet, is also the normal alphabet, called the code table; and to replace the code alphabet called the password table. This is the origin of the word password. Then move back three, this is called “three” key. Of course, learned math people understand, here are 26 letters, only in accordance with the order of mobile, each letter has 25 different alternatives, namely 25 keys, if the alphabetical order disrupted, even more key. The algorithm is through various attempts to break a code.

You can imagine, in 100 BC, which is equivalent to China period of the Western Han Dynasty, to decipher the Kaiser password, the possibility is almost zero. In cryptography, Caesar cipher is one of the most simple and most well-known encryption technology. The application is still the modern Caesar cipher in ROT13 system. But all use the alphabet to replace the encryption technology, Caesar cipher is very easy to break, but in practice also can not guarantee the communication security.

[polyalphabetic substitution]

The earliest classical cryptography mainly contains a single table substitution ciphers and polyalphabetic substitution cipher system. As the two important system in classical cryptography, has been in the ancient history of world each region is widely used. Kaiser password is a typical single table substitution.

Single table substitution in one thousand years time, is considered to be unable to crack, because of the existence of a large number of key, is fundamental to rely on manual calculation. But with the development of society and the progress of technology, from the east of the Arabs, find new technology, so as to find a shortcut to solve the considered no solution of the password, the victory was completed by the Arabia world linguists, statisticians and religion, three common.

This also indirectly thanks Chinese the invention of papermaking, the Islamic civilization spreads quickly. Because of the increased demand for books, someone needs to check the most qualified for the job is a natural theologian. They are proof at the same time, the statistics are still the revelation of Mohammed’s words frequency, if this revelation appeared new words, then it will appear a year later. In the combing process, they also found some letters appear frequency is much higher than other letters.

To learn English as we know, the letter E is the most common, followed by the letters T and a. If the encryption according to Kaiser password, a password letter corresponding code letters, then the password letters appear in the highest number could clearly should correspond to the letter E, and so on, it is easy to exclude a large number of keys to quickly find ways to break the right. Now unable to verify who is letter frequency and password linked together, but to be sure, in ninth Century, Arabs have been very good at deciphering the Kaiser password.

The Arabs from the seventh Century to the twelfth Century, the establishment of a brilliant civilization, by comparison, Europe was still ignorant and backward poverty. The prosperous of Islamic civilization, not only brought the art and science of cultural prosperity, rule and social management is also very organized and efficient. At the time of the managers, not only encrypted in the key business of government, but when the tax was also used to record them in cryptography, “document management manual” minister was still in discussion about cryptography and technical problems. It is because of the huge demand, coupled with the progress of science and technology, the Arabs finally have the opportunity to decipher the Millennium problem password replacement.

Single table substitution decoding is very simple, because the single table substitution, except for the letter name change outside, the statistical characteristics of letter frequency, mode, combined with the way of repeated letters letters were not changed, rely on these invariant statistical properties can decipher the single table substitution. The relative single table substitution, multi chart substitution is much more difficult to decipher.

How about table substitution was invented in 1467 by Florence architect Alberti. Multi chart substitution is divided into non periodic multi chart substitution and periodic table substitution ciphers. In a multi table to replace the password, use multiple letters as a password. In order to accelerate the speed of encryption or decryption, all letters are usually written in a form of cryptography, called tableau. This table is usually 26 * 26, because it can put all 26 English letters. Fill in the form and method of choice for next use letters, is different between the definition of letter replacement password. Many letters to replace the password harder to break than a single letter, because of the possibility of replacement, long before the ciphertext.

One of the most famous one is Bella cable launched in 1585 years of the Virginia code. It has not been in 1863 years before the break. The French call it “cannot decipher the password” (French: Le Chiffre ind chiffrable). This password has been mistakenly created by Blaise de Virginia, so it is called the Virginia code.

The Virginia code, the first row of the table just fill in 26 letters, then the letters in each line is shifted to the left one. (this is called table traverse, mathematics each column congruence 26.) To use this password need to use a keyword as a key. Keywords used to repeat each time. If the key word is “CAT”, express the first word by “C” encryption, the next word by “A” encryption, a third by the “T” encryption, and then return to the C encryption, repeat. Then according to the right of the encryption password table, such as the BALL CAT keyword will be encrypted to DAEN, even if it is the same “L” will be encrypted to another letter. In reality, the Virginia code keyword is very long.

Non periodic multi chart substitution, for each plaintext letter using different substitution table (or key), called the one-time password encryption, as long as the table is long enough, this is a theoretically unbreakable password only. The password can be completely hidden in plain, but because the key and plaintext message length need to widely use the same.

In order to reduce the number of the keys, in the practical application of the periodic table substitution ciphers. In sixteenth Century, there are a variety of multi table automatic key cipher is used, the Vigen re cryptosystem is the most attractive is the French http://B.de Vigtn re. The famous Vigen multi chart substitution re, Beaufort, Running-Key, Vernam and turbine (rotor machine). For a single table substitution and multi chart substitution, ciphertext analysis is feasible. Single table substitution and multi table substitution ciphers are based on a single letter as a substitution object, and each of a plurality of letters of substitution is multi letter substitution cipher. About L.Playfair in 1854 in the UK Playfair password, it was invented by British scientist C.Wheatstone. This is the first polyalphabetic substitution cipher, in the first World War the British people were using this password. The advantages of multi letter substitution is easy the natural frequency of the letters hidden or uniform and is conducive to resist statistical analysis. This password is mainly Playfair password, Hill password.

By the 1920s, people invented all kinds of mechanical equipment used for automatic processing of encryption encryption. Most of the runner is based on the concept of. In 1918 American E.H.Hebern created the first rotor turbine, it is based on a connection with the transformation of early typewriter to produce single cable alphabet instead, output through the original indicator light. The most famous is the Enigma wheel device, which is composed of the Germans invented and manufactured by Scherbius. It is in the Second World War by the germans. But during World War II, it was cracked.

Modern cryptography []

Modern cryptography research information from the originator to safe transmission and storage of the receiving terminal, is the study of “science of the enemy”. The core is the password encoding and cryptanalysis. The former is committed to building a secure password system is difficult to be an enemy or break the opponent, namely “friend”; the latter is trying to decipher the enemy or rival existing cryptosystem, namely “knowing”. Human communication password records BC 400 years. The ancient Greeks is the inventor of the replacement password. The world’s first telephone patent there confidentiality 1881. The invention of the telegraph, radio become an unavoidable research topic in the field of communication cryptography.

In the early days of the Second World War, the German military enabled “Enigma cipher machine”, a few years out of the Allied German encryption information, “Enigma cipher machine” seems to be not broken. But after the cryptanalyst’s unremitting efforts, “Enigma cipher machine” is compromised, the allies have many secrets of the German, and Germany are absolutely ignorant of the military.

The war in the Pacific, the U.S. cracked the Japanese naval cipher machine, read the Japanese fleet commander Yamamoto Igarashiroku will be sent to the commanding officer in Midway Islands, completely defeated the Japanese Navy, leading to a decisive turning point in the Pacific War, and soon killed Yamamoto fifty-six. On the contrary the axis countries, only Germany is in the early stages of the Second World War in Cryptanalysis has had a brilliant record. Therefore, we can say that cryptography plays an important role in the war.

The research focused on cryptography encoding information encryption, message authentication, digital signature and key management. The purpose of encrypted information is transformed into readable information cannot identify the contents of the information intercept these people cannot read at the same time, the information receiver can verify the received information is tampered or replaced by enemy; digital signature is the information receiver can determine whether the received information is sent by the sender to the; key management is the most difficult part of the information encryption, because the security of information encryption is the key. The history of the military intelligence agency countries than was more successful in deciphering the encryption key management method of other countries on the hunt.

Cryptanalysis of different methods and encoding the same truth, it does not depend on the mathematical logic, must rely on experience, perceive the objective world by the facts. Therefore, more people need to play the cryptanalysis ability and cleverness, more challenging.

Modern cryptography is an applied science rapid development. With the rapid popularization of the Internet, people rely on it to transfer a large amount of information, but the information transmission on the Internet is open. Therefore, the relationship to the personal interests of the information must be encrypted before they can be transmitted over the Internet, it cannot do without the modern cryptography.

In 1976, Diffie and Hellman in the “new direction” in put forward the famous D-H password key exchange protocol, marks the emergence of public key cryptography. Diffie and Hellman first proposed based on the key secret channel distribution, where the significance of this is the D-H protocol.

PKI (Public Key Infrastructure) is a security infrastructure is a pervasive public key concepts and technologies to implement and provide security services. The main task of the PKI public key infrastructure is to provide services for the digital signature open service in the open environment.

The twenty century the popularity of computer and communication systems since sixty or seventy, driven by the demand for personal safety protection and a variety of digital information service. IBM Feistel started its work in the early 1970s, 1977 peak: the research results to be adopted as a non encrypted classified information the federal information processing standard data encryption standard, DES, the most famous in the history of cryptography.

1977, the National Bureau of standards promulgated the “American data encryption standard (DES)”, the military sector monopoly password situation is broken, the civil power began the research and application of comprehensive intervention in cryptography. Has a large number of civilian encryption products sold in the market, the encryption algorithm used in DES, IDEA, RSA etc..

DES is still the standard measure of the world within the scope of many financial institutions for safety of electronic commerce, is so far as a block cipher algorithm is widely used and popular in the world. However, with the development of computer hardware and computational capabilities improve, DES is no longer safe. In July 22, 1997, the Electronic Frontier Foundation Institute (EFF) using a $250 thousand computer broke 56 DES in 56 hours. In December 1998 the United States decided not to use DES. National Institute of standards and Technology (NIST) has now enabled the new encryption standard AES, which the algorithm is research “in Belgium Rijndael”. The use of these two phases of cryptography is called symmetric cryptography, because of the system, and the secret key and the secret key are the same, and into the third stages of the development of cryptography, there is asymmetric cryptosystem, public key cryptosystem.

The existing cryptosystem thousands on thousands of different. But all of them can be divided into private key cryptosystem (DES code) and public key cryptography (such as public key cryptography). The process of encryption and decryption of the same process, but also used the same key; the latter, each user has a public secret key.

Multi Chain and asymmetric encryption []

Symmetric encryption refers to encryption and decryption using the same key, so called symmetric encryption. Only a symmetric encryption key, as a private key. Common symmetric encryption algorithms: DES, AES, 3DES and so on.

Asymmetric encryption refers to encryption and decryption using different secret key, as a public key, the other as a private key. Public key encryption information, only the private key can decrypt. The private key encryption, public key can be decrypted only. Non symmetric encryption algorithm common: RSA, ECC.

Non symmetric encryption algorithm needs two keys: a public key and a private key (publickey) (privatekey). Public key and private key is a right, if the public key to encrypt data, only using the corresponding private key can decrypt; if the private key to encrypt data, then use the public key to decrypt the corresponding. Because the encryption and decryption using two different keys, so this algorithm is called asymmetric encryption algorithm. The basic process of non symmetric encryption algorithm to achieve the exchange of confidential information is: Party A generates a pair of keys and one of them as a public key to the other side open; the public key of B using the key to encrypt the confidential information and then sent to the party; Party A and the other to preserve their own dedicated key pair the encrypted decryption information.

On the other hand, Party A Party B can use the public key to sign confidential information and then sent to Party B; Party B with its own private key to sign test data.

A dedicated key can only be decrypted by any of its public key encrypted information. Confidentiality of non symmetric encryption algorithm is better, it eliminates the need for end users to exchange keys.

The characteristics of asymmetric cryptography algorithms: the strength of the complex, security depends on the algorithm and key but because of its complicated algorithm, the encryption and decryption speed no symmetric encryption and decryption speed. There is only one key symmetric cryptosystem, and is not open, if you want to have to let each other know decryption key. So to ensure their safety is to ensure the security of the key, and asymmetric key system has two keys, one is open, so that you may not need to like each other as transmission symmetric cryptographic key. This is a great many security.

In EKT, we use the mechanism of asymmetric encryption and routing strategy combined with the implementation of private key Byzantine fault tolerance. We use multi chain EKT, a new scheme of “Multi Chain divide and rule” re designed a guarantee for each contract to the public the normal operation of the chain, which is to use the asymmetric encryption of user information is stored at the same time, the main chain and chain information sharing but function isolation. This greatly simplifies the structure innovation, reduce the pressure of data processing, to ensure that a chain traffic surge will not affect the efficiency of other chain, any business in the chain will not receive other business interference, the effective realization of resource isolation.

In the EKT Token chain is a chain of parallel multi structure, multi chain and multi consensus shared user base. EKT Token is an attribute of the chain, like the use of the utxo chain utxo model with other Token, we transfer event is also built-in.

In fact, a key problem in EKT is to solve the current difficulties of the development of the Dapp, if the use of Ethernet Fang Solidity development, need to learn a set of logical Ethernet workshop, various kinds of optimization schemes need to be considered in the complex application development, with a function to use traditional C/S structure a day finished, Ethernet square may to write a few weeks for developers is not friendly.

For example, C/S model, to write a non symmetric encryption service:

The design of a 1. server, can be calculated on a secret key pub/pri. The private key will open secure public key.

2. to design a client request server, get the server’s public pub.

3. the client through the AES to calculate the symmetric encryption key X. Then X is encrypted using pub.

4. the client sends the encrypted ciphertext to the server. The server by PRI decryption X.

5. finally will design on both sides of communication mechanism, through the symmetric key to X symmetric encryption algorithm to encrypt and decrypt.

This is a process to Dapp/ chain developers write, certainly before the real development block chain function has been the red but general steps consume too much energy and resources.

The central idea of EKT is to design a mechanism for the community, so that developers can easily develop a host DAPP backbone, the other to EKT to deal with EKT, “a chain of coins, which provides a great convenience mechanism for Multi Chain consensus” for block chain project development later, you can use in any block chain applicable scenarios. EKT provides a mechanism underlying the chain block, block chain of other projects can be easily the backbone of EKT code based on the deployment of a set of their own backbone. Block chain project compiled on the EKT will not need to worry too much about security issues, because each interface is very simple and deployed in many parallel backbone and operation. When the main chain can be flexibly deployed to issue their own tokens and the selection of backbone consensus algorithm. The newly deployed backbone can be added to the EKT chain technology, the entire ecosystem, sharing EKT ecological resources users, and EKT tokens can also coins and tokens of other backbone exchange and circulation.

Each node of the EKT public key chain are open. This is a balance between efficiency and safety and to the center of the solution. Token is generally defined as an intelligent contract, but if it becomes a defining event in advance of the “object”, the “object” can have their parameters (such as total, consensus mechanism etc.), security will bring a better experience. Take the address of the token can have two types: ordinary user address and address the contract, the contract after receiving the token address to perform non Turing complete language can be a simple contract, state calculation and token transfer.

The above is I to block chain cryptography some thinking, and some in the design of EKT Multi Chain consensus on the construction of asymmetric encryption and the underlying consideration. Welcome to ask questions, discuss.

[SHA-1].

Block chain game player should have a word very familiar — hash.

Hash, generally translated as “hash” in academic circles, the programmer directly transliterated as “Hashi”, it is the operation of arbitrary length of the input (also called pre mapping pre-image) into a fixed length output through the hash algorithm transform, the output is the hash value. This conversion is a contractive mapping, that is, the hash value space is much smaller than the input space, different input may be hashed into the same output, so it is not possible to determine the only input value from a hash value. Is simply a compress messages of arbitrary length to a fixed length message digest function.

All hash functions have a basic characteristics: if two hash values are not the same (according to the same function), then the two input hash value is not the same. This is a hash function with deterministic results, the hash function with this property is called one-way hash function. But on the other hand, the hash function of the input and output is not only the corresponding relationship between the two, if the same hash value, two input values is likely to be the same, but can be different, this is called a hash collision (collision) “, which is usually two different lengths of the input value, deliberate calculation the same output value. The hash value calculation of the input data, then part of the change of input value, a strong characteristic of confusion of the hash function will produce a completely different hash value.

Hash functions need to meet the following conditions:

A.: deterministic hash algorithm is a deterministic algorithm, algorithm implementation does not introduce any random quantity. This means that the hash of the same message the same.

B. efficiency: a m message given, can quickly calculate the HASH (m).

C. target collision resistance: a M0 message given, it is difficult to find another M1 message, the HASH (M0) = HASH (M1)

D. generalized collision resistance: it is difficult to find the two message M0 is not equal to M1, the HASH (M0) = HASH (M1).

In cryptography, is generally believed that if the D condition is not satisfied, then the hash function is no longer safe. In fact, if considered to some extent C condition is not satisfied, then the hash function is no longer safe. Of course, if C does not meet the conditions, then the hash function has been completely unsafe, should be directly discarded.

The actual application of hash general called secure hash algorithm, (English: Secure Hash Algorithm, abbreviated as SHA), it is a secure hash algorithm FIPS authentication, is a cryptographic hash function family. Can calculate a digital message corresponding to the fixed length string (also called the message digest algorithm). And if the input message is different, they correspond to the probability of different string is very high (previously thought to be infinitely close to 99.99999999%, why is the former, explained later).

Cryptography is an ancient discipline, has a long and wonderful history. It is used to protect military and diplomatic communication can be traced back to ancient times, thousands of years ago just the text. For thousands of years, has been moving forward constantly in cryptography. From the beginning of the Kaiser code, people in the development of new cryptographic algorithms are diligently crack existing cryptographic algorithms, because of the crack, the higher the password difficulty, means a secret value behind the guard is bigger. Five algorithms of the SHA family, including SHA-1, SHA-224, SHA-256, SHA-384, and SHA-512, after several general can also be referred to as SHA-2, by the U.S. National Security Agency (NSA) design, and study by the National Institute of standards and Technology Institute (NIST) released; is the United States government standard. Is also a large number of Internet and electronic products the key keeper.

SHA series of Hash function family is the most well-known function of Hash family, MD5, SHA-1 and SHA-2 have been widely used, the use of bitcoin is SHA-2 in the series SHA-256 hash algorithm. 1990 years MD4 algorithm was proposed, but was found to have serious safety problems quickly, in 1992 years to replace the MD5 algorithm. MD5 algorithm after ten years has been widely used in software industry, until 2004 China cryptographer Wang Xiaoyun in the annual international cryptology Conference (CRYPTO) shows the MD5 algorithm and gives the first instance of collision. The attack complexity is very low, only a few seconds in a computer. In 2005, Professor Wang Xiaoyun and his colleagues also proposed a collision algorithm of SHA-1 algorithm (Finding Collisions in the Full SHA-1, CRYPTO 2005), but the computational complexity is 69 ^ 2, it is difficult to achieve in the actual situation.

Until last year, (2017) 2 November 24, Google released their amazing results, announced the case of a SHA-1 hash collision instance, which is published or even make cryptographists most famous for its top CRYPTO the modified results postponed 19 hours. Because of the simple Google, the basic SHA-1 death sentence. In this work before the announcement, most website HTTPS certificate relates to the use of the SHA-1 algorithm, many version control tools and a variety of cloud synchronization services including GitHub, SHA-1 is used to distinguish between documents, many security certificates or signatures also used SHA-1 to guarantee uniqueness. For a long time, people think SHA1 is very safe, at least we have not found a collision case, but now have to consider the safety of users began to upgrade to SHA-2 or other algorithms.

CWI and Google researchers have successfully found a case of SHA1 collision, and very powerful, the collision of the two is true, can read PDF files. The two contents of the PDF file is not the same, but the SHA1 value is exactly the same.

The results of this study: why so compelling? This is because we all know that the hash collision may exist, but as long as the collision to create support system, hash algorithm is safe, and we always think before the collision case is difficult to achieve SHA1. Google proved that this argument is untenable, especially now in the GPU parallel computing has been a wide range of application conditions. Google 110 GPU, after one year, a total of 9 exascale computing (total 9223372036854775808) created this collision — a case study of the process of calculation time cost is huge, but it is now very common large-scale computing center, is not difficult to achieve. This means that the current implementation of the computation time for the collision attack SHA1 still need massive.

MD5 and SHA-1 has not recommended to be used, but it does not say they have completely outdated. In fact, the existing various excellent cryptographic algorithms are set up on the basis of the old algorithm, and the old algorithm system is often not because of the inherent vulnerabilities and the rapid development of computing power led people to abandon, we must constantly change the basic algorithm, to meet the needs of the production environment and avoid a potential security risk. We also have to keep the view with the new vision and processing work, when new technological breakthroughs occur immediate attention, not hidebound, conservative. SHA-1 and SHA-2 are two different versions of the SHA algorithm, the structure and the length of their signature are not the same, but SHA-2 can be understood as a successor to SHA-1. 256 use bitcoin using SHA-256 to SHA-2, the year (2008) Nakamoto bitcoin writing, not taking into account the SHA algorithm so soon to be cracked, but fortunately all kinds of digital currency later encryption algorithm used more harder to crack, you can turn back to the concrete before I write “how to encrypt” series of encryption currency. But from the SHA-1 Google break, all bearing a huge market capitalization of encryption currency should arouse vigilance, because maintaining the benefit of consensus, or must be set up on the basis of encryption algorithm.

[hidden] quantum computing

But if the existing encryption method of all digital currency failure, what will become of the world?

This sounds a bit fanciful idea is not far away from us. When after a dozen years of practical quantum computer is greatly improved, the existing mathematical complexity rely on to ensure the safety of the asymmetric key encryption methods are likely to all failure. Academician Guo Guangcan had mentioned in his speech, 2000qubit quantum computer using shor algorithm can be completed in 1s large number RSA algorithm security dependent decomposition calculation based on.

What is the first simple talk about quantum computing. Qubits can be prepared in the two logic state of 0 and 1 of the coherent superposition state, in other words, it can also store 0 and 1. Consider a N a bit of physical memory, if it is a classic memory, it can only store 2^N possible any data, if it is a quantum memory, it can also store the number of 2^N, and with the increase of N, its ability to store information in the index rose, for example, a memory the 250 qubit (with 250 atoms) may be stored number up to 2^250, more than the known universe all atom number. The mathematical operation can be simultaneously all of the data in memory, therefore, quantum computer can simultaneously 2^N input the number of mathematical calculations in the implementation of an operation. The effect is equivalent to the classical computer to repeat the implementation of 2^N operation, or use 2^N different processors implement concurrent operation. Therefore, quantum computer can save a large amount of computing resources (such as time, memory etc.).

Quantum computer is not a faster computer. In logic, output mode and classic computer is different, the most essential is that the existence of entanglement. In the viewpoint of quantum information theory, quantum entanglement is a kind of natural resources is juxtaposed with material and energy and information, and make good use of the resources to be able to make quantum computers play a great power. However, how to design a faster algorithm for it, in theory, is a great challenge. At present, most of the computational problems, theorists have not yet found a quantum algorithm than the classical algorithm; but in some special problems is a new discovery. What are the problems? The earliest discovered there are twocategories: one can be attributed to the factorization (Shor algorithm), than the fastest known classical algorithms have exponential speedup (exactly is super polynomial acceleration); another kind can be attributed to random search (Grove algorithm), than the classical algorithm has polynomial acceleration.

Shor algorithm and Grove algorithm respectively in 1994 and 1996 is put forward, that can be said is that they found caused the real importance of science of quantum computing, although preliminary concepts of quantum computing had already appeared in the 80 in the early 1980s, but ten years are only a very small circle of game theory, is thought to be unable to implementation is of no use; Shor algorithm and Grove algorithm to find the possible practical applications finally for quantum computer. The effect of Shor algorithm — especially in modern cryptography, several kinds of commonly used public key system including RSA (Rivest Shamir Adleman) and ECC (elliptic-curve cryptography) as the basic principle of encryption is the decomposition of large numbers of computational complexity. Therefore, quantum computers once, will give the existing information security threat, encryption algorithm for almost all existing currency cannot withstand a single blow. Incidentally, ECC bitcoin is the use of encryption mode.

University of Waterloo School of quantum computing co-founder Michele Mosca (also the Perimeter Institute for theoretical physics researchers) that we use some encryption tools, to 2026 years have the probability of 1/7 was cracked; in the 2031 year, this figure will rise to 50%. That is to say, at that time, if we still use the encryption mechanism now, even if the network data transmission is encrypted, also can use brute force to decrypt it is quantum computing can bring convenience”.

Some people think that quantum computation can bring an improvement to break the encryption algorithm, then can use the quantum algorithm to direct encryption? The answer is feasible but currently unknown. The essential equipment in quantum cryptography, is also the most expensive component is a photon detector in the existing (or near future) conditions, launched a quantum computing attacks can have people willing to pay for the huge gains, but if the use of quantum encryption algorithm of the digital currency have adopted this type of machine. It is impossible to bear the pain of the cost, but the next ten or twenty years will be what kind of magical things, who can predict?

[EKT] thinking

In 1970s, researchers from the British intelligence and academic institutions independently invented the asymmetric encryption methods. Using two different keys: a public key and a private key. In the encryption process a transaction, both keys are required. For example, in online shopping, the public key is sent to the server provider consumer computer, the key is public, all consumers can be obtained and used. Consumers with a computer the public key encryption key, which will serve as a symmetric key shared with suppliers. Received after symmetric key encryption, server vendors will use a unique private key to decrypt. Once the two sides to securely share the symmetric key, you can complete the transaction with the following encryption.

Non symmetric encryption algorithm needs two keys: a public key and a private key (publickey) (privatekey). Public key and private key is a right, if the public key to encrypt data, only using the corresponding private key can decrypt; if the private key to encrypt data, then use the public key to decrypt the corresponding. Because the encryption and decryption using two different keys, so this algorithm is called asymmetric encryption algorithm. The basic process of non symmetric encryption algorithm to achieve the exchange of confidential information is: Party A generates a pair of keys and one of them as a public key to the other side open; the public key of B using the key to encrypt the confidential information and then sent to the party; Party A and the other to preserve their own dedicated key pair the encrypted decryption information.

On the other hand, Party A Party B can use the public key to sign confidential information and then sent to Party B; Party B with its own private key to sign test data. A dedicated key can only be decrypted by any of its public key encrypted information. Confidentiality of non symmetric encryption algorithm is better, it eliminates the need for end users to exchange keys.

In EKT, we use the mechanism of asymmetric encryption and routing strategy combined with the implementation of private key Byzantine fault tolerance. We use multi chain EKT, a new scheme of “Multi Chain divide and rule” re designed a guarantee for each contract to the public the normal operation of the chain, which is to use the asymmetric encryption of user information is stored at the same time, the main chain and chain information sharing but function isolation. This greatly simplifies the structure innovation, reduce the pressure of data processing, to ensure that a chain traffic surge will not affect the efficiency of other chain, any business in the chain will not receive other business interference, the effective realization of resource isolation.

In the EKT Token chain is a chain of parallel multi structure, multi chain and multi consensus shared user base. EKT Token is an attribute of the chain, like the use of the utxo chain utxo model with other Token, we transfer event is also built-in.

In fact, a key problem in EKT is to solve the current difficulties of the development of the Dapp, if the use of Ethernet Fang Solidity development, need to learn a set of logical Ethernet workshop, various kinds of optimization schemes need to be considered in the complex application development, with a function to use traditional C/S structure a day finished, Ethernet square may to write a few weeks for developers is not friendly. This is a process to Dapp/ chain developers write, certainly before the real development block chain function has been the red but general steps consume too much energy and resources.

In EKT, insist on such a concept, the development of Turing complete language does not require a monetary system, for different applications as much as possible to achieve the principle of isolation. So we in the design, the processing of DApp and token separately, that is to say there are two types of chain in EKT: token and DApp chain.

The token chain is dedicated to a chain of processing token transactions, in view of the various vulnerabilities ERC20 tokens constantly exposed (although the vulnerability is intelligent contract developers, but we think there is a better solution to realize) in EKT, built-in token object, the amount of developers only need to define your own token hair. In addition, the EKT token chain is a multi chain consensus, that is to say the different token can be placed in different token chain packing, multi chain parallel transaction processing speed is greatly improved.

The EKT DApp chain is a chain for different developers DApp. Our contract from smart development language, data storage (without proof of storage space with Merkel Merkel proved and private), 3 efficiency is optimized. The EKT DApp chain basically can be achieved with the Internet now using the same even faster development, there is not much difference function can be realized with the application of the Internet, the most important is that we can achieve the second most event execution and confirm the safety requirements higher than the events can be realized to confirm 3.

The central idea of EKT is to design a mechanism for the community, so that developers can easily develop a host DAPP backbone, the other to EKT to deal with EKT, “a chain of coins, which provides a great convenience mechanism for Multi Chain consensus” for block chain project development later, you can use in any block chain applicable scenarios. EKT provides a mechanism underlying the chain block, block chain of other projects can be easily the backbone of EKT code based on the deployment of a set of their own backbone. Block chain project compiled on the EKT will not need to worry too much about security issues, because each interface is very simple and deployed in many parallel backbone and operation. When the main chain can be flexibly deployed to issue their own tokens and the selection of backbone consensus algorithm. The newly deployed backbone can be added to the EKT chain technology, the entire ecosystem, sharing EKT ecological resources users, and EKT tokens can also coins and tokens of other backbone exchange and circulation.

In the design of EKT encryption system, after our team had seriously considered SHA-1 crack and the future development of quantum computing technology of block chain in the world, even once wanted to set out to achieve this seemingly fancy function. But after careful consideration, we decided the team will now be limited resources as much as possible into the platform development work, at the same time, I and several colleagues will pay close attention to the progress of encryption currency security, maintain reference and follow the latest academic trends of safety.

The above is I to block chain cryptography some thinking, and some in the design of EKT Multi Chain consensus on the construction of asymmetric encryption and the underlying consideration. Welcome to ask questions, discuss.

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