Mining algorithm nist5

1. Sha family
Sha (secure hash algorithm) is a series of cryptographic hash functions designed by National Security Agency (NSA) and published by National Institute of standards and Technology (NIST). The first member of the family officially named Sha was published in 1993. However, it has now been given an informal name sha-0 to avoid confusion with its successors. Two years later, SHA-1, the successor of the first Sha, was released. There are also four variants that have been released to enhance the scope of output and to change some minor designs: sha-224, SHA-256, sha-384, and sha-512 (sometimes referred to as SHA-2)<
sha-0 and SHA-1
the algorithms originally specified were published in 1993, which are called secure hash standard, FIPS pub 180. This version is now often called & quot; SHA-0" It was withdrawn by NSA soon after its release, and released in 1995 as a revised version of FIPS pub 180-1 (commonly known as & quot; SHA-1") replace. According to NSA, it fixed an error in the original algorithm that would rece password security. However, NSA does not provide any further explanation or proof that the error has been corrected. In 1998, in an attack on sha-0, it was found that this attack was not applicable to SHA-1 - we don't know if this is the error found by NSA, but it may indicate that this correction has improved the security. SHA-1 has been closely examined by the public password community, but it has not been found to be unsafe. It is now considered safe
sha-0 and SHA-1 will generate a 160 bit digest from a message with a maximum size of 2 ^ 64 bits, and then encrypt it based on the similar principle of Ronald L. Rivest, Professor of MIT who designed MD4 and MD5 message digest algorithms<
Cryptanalysis of sha-0
on crypto 98, two French researchers demonstrated an attack on sha-0 (chabaud and joux, 1998): hash collision can be found when the complexity is 2 ^ 61; Less than 2 ^ 80 is an ideal hash function of the same size
in 2004, Biham and Chen discovered the approximate collision of sha-0 - two messages can hash out the same value; In this case, 142 and 160 bits are the same. They also found that sha-0 dropped to 62 bits after 80 full collisions
on August 12, 2004, joux, carribault, lemuet and jalby announced the hash collision of the complete sha-0 algorithm. This is the result of the attack of chabaud and joux. The collision was found to be 2 ^ 51, and it took about 80000 CPU hours to work on a supercomputer with 256 Itanium 2 processors< On August 17, 2004, Wang, Feng, Lai, and Yu announced the preliminary results of attacking MD5, sha-0, and other hash functions at the rump meeting of crypto 2004. Their attack on sha-0 is as complex as 2 ^ 40, which means that their attack results are better than those of joux and others. A brief summary of the rump meeting can be found here, and their discussions in sci.crypt, for example, suggest that people planning to use SHA-1 as a new cryptosystem need to reconsider
longer variants
NIST has released three additional Sha variants, each with a longer message digest. They are named by adding their summary length (in bits) after their original name: & quot; SHA-256", & quot; SHA-384" And & quot; SHA-512" They were published in the draft of FIPS pub 180-2 in 2001, and then passed the review and comments. FIPS pub 180-2, including SHA-1, was released as an official standard in 2002. These new hash functions have not been tested in detail by the public password community like SHA-1, so their password security is not widely trusted. In February 2004, a change notice of FIPS pub 180-2 was issued, and an additional variant was added; SHA-224"， The key length required for double key 3DES is defined
Gilbert and handschuh (2003) studied new varieties and found no weaknesses<
shad
shad function is a simple restatement of the same Sha function:
shad-256 (m) = SHA-256 (SHA-256 (m)). It overcomes the problem of extended length attacks
applications
SHA-1, sha-224, SHA-256, sha-384 and sha-512 are all used by the U.S. federal government, which needs secure hash algorithms. They also use other cryptographic algorithms and protocols to protect sensitive unclassified data. FIPS pub 180-1 also encourages private or commercial organizations to use SHA-1 encryption. Fritz chip will probably use SHA-1 hash function to realize digital rights management on personal computers
the first to promote the publication of secure hash algorithm is the combined digital signature standard
Sha hash function has been used as the basis of shacal block cipher algorithm<
description of SHA-1
the pseudocode of SHA-1 algorithm is as follows:
(initialize variables:)
A = H0 = 0x67452301
b = H1 = 0xefcdab89
C = h2 = 0x98badcfe
d = H3 = 0x10325476
e = H4 = 0xc3d2e1f0
(pre processing:)
paddedmessage = (message) append 1
while length (paddedmessage) mod 512 & gt; 448:
paddedmessage = paddedmessage append 0
paddedmessage = paddedmessage append (length(message) in 64-bit format)
(Process the message in successive 512-bit chunks:)
while 512-bit chunk(s) remain(s):
break the current chunk into sixteen 32-bit words w(i), 0 <= i <= 15
(Extend the sixteen 32-bit words into eighty 32-bit words:)
for i from 16 to 79:
w(i) = (w(i-3) xor w(i-8) xor w(i-14) xor w(i-16)) leftrotate 1
(Main loop:)
for i from 0 to 79:
temp = (a leftrotate 5) + f(b,c,d) + e + k + w(i) (note: all addition is mod 2^32)
where:
(0 <= i <= 19): f(b,c,d) = (b and c) or ((not b) and d), k = 0x5A827999
(20 <= i <= 39): f(b,c,d) = (b xor c xor d), k = 0x6ED9EBA1
(40 <= i <= 59): f(b,c,d) = (b and c) or (b and d) or (c and d), k = 0x8F1BBCDC
(60 <= i <= 79): F (B, C, d) = (b XOR C XOR d), k = 0xca62c1d6
e = d
d = C
C = B leftrotate 30
b = a
A = temp
H0 = H0 + a
H1 = H1 + B
h2 = H2 + C
H3 = H3 + d
H4 = H4 + e
digest = hash = H0 append H1 append H2 append H3 append H4
note: FIPS pub 180-1 shows the concept of, The efficiency can be improved by using the following formula:
(0 & lt= i <= 19): f(b,c,d) = (d xor (b and (c xor d)))
(40 <= i <= 59): f(b,c,d) = (b and c) or (d and (b or c)))

2. Unknown_Error

3.

There are five meanings

1, the brand Neo of Adidas

Adidas Neo belongs to Adidas sports and leisure series, which is the freshest sports and leisure brand integrated into your daily life. Adidas Neo means fresh and energetic, full of optimism, full of movement, personal affinity, fresh and advancing with the times

2, Neo (Polish eSports)

Polish eSports. In 2012, Neo played an outstanding role in the super death group, and fought with the Ukrainian emperor Na ` VI to win the IEM world finals. In September of the same year, it announced the formal transformation of CS: go. After hard training, ESC team finally won the first championship after the transformation of CS: go at the end of 2012

The most frightening thing about Neo is that it will eat all the creatures in front of it. Neo's belly is completely another world, and being swallowed by it is equivalent to permanent disappearance. Although Neo has also died, it will always come back to life. No matter how powerful the opponent is, it will be doomed. Neo is a nightmare forever. In short, the most terrible thing about Neo is not strength, but endless appetite

Neo, also known as pirate boss, is 1000 years old and 2 meters tall. He is the boss of the space pirate Obi organization and the captain of the ghost. He first appeared in the mission "decisive battle with the ghost", and is one of the biggest enemies of the sail. He has four capable generals: bit, Zog, Alison and Dean (later betrayed)

5, Neo (contact lens brand)

Neo, Chinese name "anthracene Yiao". It is affiliated to Neo vision company of South Korea. Neo vision is one of the largest stealth companies in South Korea. It has repeatedly won the championship in terms of stealth sales in Japan and South Korea. Neo vision's contact lenses occupy 80% of South Korea's lens market

{rrrrrrr}

extended materials:

on November 27, 2017, Adidas Neo officially announced that the new generation of youth idol, e-close Qianxi, has become Adidas Neo's new brand spokesman and the first global youth creative officer

As a global youth representative, Yixiang Qianxi will give full play to its creative inspiration and bring more unexpected surprises to the global youth group together with Adidas Neo. In the future, Adidas Neo will join hands with Yiguan Qianxi to create more exciting "born active" brand activities, and share more active vitality and new experience with young groups

4. Subway line 2
Lujiazui Station
Exit 6
is just in front of you

5.

The algorithm has five important characteristics, including finiteness, accuracy, input term, output term and feasibility

1, finiteness

the finiteness of the algorithm means that the algorithm must be able to terminate after a finite number of steps

Each step of the algorithm must have an exact definition

3. Input

an algorithm has 0 or more inputs to describe the initial condition of the operation object. The so-called 0 input means that the algorithm itself determines the initial condition

4. Output

an algorithm has one or more outputs to reflect the results of processing input data. The algorithm without output is meaningless

5, effectiveness

any calculation steps in the algorithm can be decomposed into basic executable operation steps, that is, each calculation step can be completed in a limited time (also known as effectiveness)

extended data

1, Dijkstra algorithm

this graph search algorithm has a variety of applications, which can model the problem to be solved as a graph and find the shortest path between two nodes

RSA algorithm

this algorithm is developed by the founders of RSA company, which makes the cryptography achievements available to everyone in the world at will, and even shapes the implementation mode of today's cryptography technology

This is not a real algorithm, but a series of cryptographic hash functions developed by NIST. However, the algorithm family plays a crucial role in maintaining the world order

The purpose of this algorithm is to control the error between the expected output signal and the actual output signal to the greatest extent by using the feedback mechanism of the control loop. It is suitable for all scenarios with signal processing requirements, including mechanical, hydraulic or thermal systems controlled by electronic technology in an automatic way

5, data compression algorithm

it is difficult to determine which compression algorithm is the most important, because according to the actual application requirements, the algorithms we use may include zip, MP3 and even JPEG, MPEG-2 and so on

6. How to match the mass spectrum data with NIST database
1. To create a user named configuration file: you can select the options / save options command from the options menu to save all the configuration of the current integrated development environment into a user named configuration file. Next time you start TC, just type in DOS:
TC / C & lt; User named profile name & gt
the content in this configuration file will be selected as turbo c 2.0
2. If options / environment / config auto save is set to on, the current settings will be automatically saved to tcconfig.tc when exiting the integrated development environment. Turbo C automatically looks for this configuration file at startup
3. Use tcinst to set the configuration of Turbo C and store the results in tc.exe. When Turbo C starts, if no configuration file is found, the default value in tc.exe will be taken< br /> C language 2
2 soul of program algorithm
2.1 concept of algorithm
2.2 simple algorithm examples
2.3 characteristics of algorithm
2.4 how to express an algorithm
2.4.1 algorithm in natural language
2.4.2 algorithm in flow chart
2.4.3 three basic structures and improved flow chart
2.4.4 algorithm in N-S flow chart
2.4 5 using pseudo code to represent algorithm
2.4.6 using computer language to represent algorithm
2.5 structured programming method
2 soul algorithm of program

7. AES (the advanced encryption standard) is a standard used by National Institute of standards and technology for encrypting electronic data. It is expected to become a recognized method of encrypting digital information including finance, telecommunications and government. National Institute of standards and Technology (NIST) established a new advanced data encryption standard (AES) specification on May 26, 2002. AES is a new encryption algorithm which can be used to protect electronic data< In 1998, National Institute of standards and Technology (NIST) started the first round of AES analysis, testing and collection, and proced 15 candidate algorithms. It includes cast-256, CRYPTON, deal, DFC, E2, frog, HPC, loki97, magenta, Mars, RC6, Rijndael, safer +, serpent and Twofish. Five candidate algorithms entered the second round: Mars, RC6, Rijndael, serpent, and Twofish. NIST developed a new advanced encryption standard (AES) specification on May 26, 2002

AES is a typical symmetric encryption algorithm, which is widely used. The sender will process the plaintext and encryption key together with a special encryption algorithm to make it become a complex encrypted ciphertext and send it out. After receiving the ciphertext, if the receiver wants to interpret the original text, it needs to decrypt the ciphertext with the encryption key and the inverse algorithm of the same algorithm, so that it can be restored to readable plaintext. In symmetric encryption algorithm, only one key is used. Both sender and receiver use this key to encrypt and decrypt the data, which requires the decryptor to know the encryption key in advance. The advantage of symmetric encryption algorithm is that the algorithm is open, the amount of calculation is small, the encryption speed is fast and the encryption efficiency is high. The disadvantage is that both sides use the same key, so the security is not guaranteed

in this digression, asymmetric encryption algorithms, such as the famous RSA algorithm, use two completely different but perfectly matched keys -- public key and private key. When asymmetric encryption algorithm is used to encrypt files, only a pair of matching public key and private key can complete the process of plaintext encryption and decryption. Public key encryption is used to encrypt plaintext, and private key is used to decrypt ciphertext. Moreover, the encryptor knows the public key of the receiver, and only the decryptor is the only one who knows his private key< The AES algorithm is based on permutation and permutation. Permutation is to rearrange data, and permutation is to replace one data unit with another. AES uses several different methods to perform permutation and permutation operations. AES is an iterative, symmetric key block cipher, which can use 128, 192 and 256 bit keys, and encrypt and decrypt data with 128 bit (16 byte) blocks. Unlike public key encryption using key pairs, symmetric key cryptography uses the same key to encrypt and decrypt data. The number of bits of encrypted data returned by block cipher is the same as that of input data. Iterative encryption uses a loop structure in which input data is repeatedly replaced and replaced. According to records, in 400 BC, the ancient Greeks invented the replacement code. In 1881, the first patent of telephone secrecy appeared in the world. During the Second World War, the German military used the enigma cipher, and cryptography played a very important role in the war

the AES encryption process is in a 4 × This matrix is also called "state". Its initial value is a plaintext block (the size of an element in the matrix is a byte in the plaintext block). During encryption, each round of AES encryption cycle (except the last round) includes four steps:

1. Addroundkey - every byte in the matrix is XOR with the round key; Each subkey is generated by the key generation scheme
2. Subbytes - each byte is replaced by its corresponding byte by a look-up table through a non-linear replacement function
3. Shiftrows - circularly shift each column in the matrix
4. MixColumns - to fully mix the operations of each row in the matrix. This step uses a linear transformation to mix four bytes per inline.