Asymmetric encryption algorithm of blockchain in Internet of veh
asymmetric encryption algorithm is a function that converts the original plaintext file or data into a series of unreadable ciphertext codes by using an encryption key. The encryption process is irreversible. Only holding the corresponding decryption key can the encrypted information be decrypted into readable plaintext. Encryption enables private data to be transmitted through the public network under the condition of low risk, and protects the data from being stolen and read by the third party
the core advantage of blockchain technology is decentralization, which can realize point-to-point transaction, coordination and cooperation based on decentralized credit in a distributed system without mutual trust by means of data encryption, time stamp, distributed consensus and economic incentive, so as to solve the high cost and low cost of centralized institutions Low efficiency and data storage insecurity provide solutions
the application fields of blockchain include digital currency, token, finance, anti-counterfeiting traceability, privacy protection, supply chain, entertainment, etc. with the popularity of blockchain and bitcoin, many related top domain names have been registered, which has a great impact on the domain name instry.
Take subway line 1, transfer to line 2 at people's Square Station, get off at Century Avenue station, and then transfer to line 6
the line identification color of Shanghai Rail Transit Line 6 is magenta
development information: Shanghai Metro Line 6 runs through the whole Pudong New Area, starting from Gangcheng road of Gaoqiao Town in the north and reaching Sanlin area in the south, and is operated by Shanghai Metro No.4 Operation Co., Ltd
Shanghai Rail Transit Line 6 is based on the rail transit network fare system approved by the municipal price department, that is, the multi-level fare based on mileage is implemented for rail transit, which is 3 yuan for 0-6 km, and 1 yuan for every 10 km after 6 km. The fare calculation of line 6 adopts the shortest route method, that is, when there is more than one transfer route between two stations, the shortest route is selected as the basis for fare calculation between two stations
the characteristics of asymmetric cryptosystem: the strength of the algorithm is complex, and the security depends on the algorithm and the key, but because of the complexity of the algorithm, In symmetric cryptosystem, there is only one kind of key, and it is not public. If you want to decrypt, you have to let the other party know the key. So to ensure its security is to ensure the security of the key. Asymmetric cryptosystem has two kinds of keys, one of which is public, In this way, you don't need to transfer the other party's key like symmetric password, so the security is much greater.
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unlike symmetric encryption technology, which only uses one secret key, asymmetric encryption technology uses two secret keys for encryption and decryption, one is called public key and the other is called private key. The private key is kept by itself, and the public key can be made public. Data encrypted by public key must be decrypted by private key, and vice versa. Public key and private key are two different secret keys, Because this encryption method is called asymmetric few second technology. Compared with symmetric encryption technology, asymmetric encryption technology has better security but slower performance
in the Internet back-end technology, asymmetric encryption technology is mainly used for login, digital signature, digital certificate authentication and other scenarios<
the commonly used asymmetric encryption algorithms are:
RSA: RSA is an asymmetric secret key encryption technology which is widely used and has a long history. In 1977, it was proposed by three scientists, Ron Rivest, ADI Shamir and Leonard Adleman of MIT, Because of its difficulty to solve, RSA is the most widely used digital encryption and signature technology, for example, the domestic Alipay is using RSA algorithm to carry out signature verification. Its security depends on the length of the secret key. At present, the mainstream secret key lengths are 1024 bits, 2048 bits, 4096 bits and so on. In theory, the longer the secret key, the more difficult it is to crack. According to wiki, a secret key with 256 bits or less can be cracked in a few hours on a personal computer. A 512 bit secret key and a 768 bit secret key were successfully cracked in 1999 and 2009 respectively, Although there is no public information to confirm that someone can successfully crack the 1024 secret key, it is obviously not far away from the node, so the instry recommends 2048 or more secret keys. However, at present, the secret key of 2048 places is safe enough. The recommendation on Alipay's official documents is 2048, of course, the longer secret key is more secure. But it also means more performance overhead< DSA: digital signature algorithm, which was proposed by NIST in 1991. Different from RSA, DSA can only be used for digital signature, but not for data encryption and decryption. Its security is equivalent to RSA, but its performance is faster than RSA<
ECDSA: elliptic curve digital signature algorithm, is the combination of ECC (elliptic curve cryptography) and DSA. The use of elliptic curve in cryptography was independently proposed by Neal Koblitz and Victor Miller in 1985. Compared with RSA algorithm, ECC can use smaller secret key and has higher efficiency, It is said that the security of 256 bit ECC secret key is equivalent to 3072 bit RSA secret key. Compared with ordinary DSA, ECDSA uses elliptic curve algorithm in calculating secret key.
RSA, ElGamal, knapsack algorithm, Rabin, D-H, ECC (elliptic curve encryption algorithm)
RSA algorithm is the most widely used, and ElGamal is another commonly used asymmetric encryption algorithm
ElGamal was invented by Taher ElGamal in 1985, based on Diffie ˉ Hellman key exchange algorithm, which enables both sides of communication to dece the secret key value [Diffie] only they know through public communication ˉ Hellman] Diffie ˉ Hellman, invented by Whitfield Diffie and Martin Hellman in 1976, is regarded as the first asymmetric encryption algorithm, Diffie ˉ Hellman differs from RSA in that Diffie ˉ Hellman is not an encryption algorithm, it just generates secret values that can be used as symmetric keys. In Diffie ˉ In the process of Hellman key exchange, the sender and the receiver generate a secret random number respectively, and derive the public value according to the random number, and then exchange the public value. Diffie ˉ Hellman algorithm is based on the ability to generate shared key. As long as the public value is exchanged, both sides can use their own private number and the public value of the other side to generate a symmetric key, which is called shared key. For both sides, the symmetric key is the same and can be used to encrypt data using symmetric encryption algorithm
compared with RSA, Diffie ˉ One of the advantages of Hellman is that each time the key is exchanged, a new set of values is used. When RSA algorithm is used, if the attacker obtains the private key, he can not only decrypt the previously intercepted messages, but also decrypt all the subsequent messages. However, RSA can prevent man in the middle attacks by authentication (such as using X.509 digital certificate), but Diffie does not ˉ Hellman is vulnerable to man in the middle attacks
asymmetric encryption algorithm
features:
both sender and receiver have a key pair (public key + private key), in which the public key is propagated and the private key is saved by itself, There is no need to propagate
the private key does not need to propagate, which solves the difficulty of key propagation in symmetric encryption algorithm (this difficulty can be generally solved by offline transmission)
encryption is highly secure, and it is only used for some e-commerce websites, and the encryption and decryption speed is far lower than symmetric encryption
generally, in order to solve the problem of low encryption and decryption speed of asymmetric encryption algorithm, Asymmetric encryption (using public key and private key to encrypt and decrypt symmetric encryption key) + symmetric encryption (encrypting and decrypting data) is adopted
common algorithms:
DH (the cornerstone of asymmetric encryption)
RSA (the classic of asymmetric encryption, which can be used not only for asymmetric encryption, but also for digital signature, RSA -- 155 (512 bit key) has been cracked)
ElGamal
asymmetric encryption algorithm needs two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt the data, only the corresponding private key can be used to decrypt it; If the private key is used to encrypt the data, only the corresponding public key can be used to decrypt. Because encryption and decryption use two different keys, this algorithm is called asymmetric encryption algorithm. The basic process of asymmetric encryption algorithm to realize confidential information exchange is: Party A generates a pair of keys and publishes one of them as a public key to other parties; Party B who obtains the public key uses the key to encrypt the confidential information and then send it to Party A; Party A will decrypt the encrypted information with another private key. On the other hand, Party A can use its own private key to encrypt the confidential information and then send it to Party B; Party B shall decrypt the encrypted information with Party A's public key
Party A can only use its private key to decrypt any information encrypted by its public key. Asymmetric encryption algorithm has better confidentiality, it eliminates the need for end users to exchange keys
the characteristics of asymmetric cryptosystem: the algorithm strength is complex, and the security depends on the algorithm and key, but the speed of encryption and decryption is not as fast as that of symmetric encryption and decryption because of its complex algorithm. There is only one key in symmetric cryptosystem, and it is not public. If you want to decrypt, you have to let the other party know the key. So to ensure its security is to ensure the security of the key, and asymmetric key system has two kinds of keys, one of which is public, so that it does not need to transmit the other party's key like symmetric password. So the security is much greater.
Asymmetric encryption algorithm is a secret key method. Asymmetric encryption algorithm needs two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt the data, only the corresponding private key can be used to decrypt it; If the private key is used to encrypt the data, only the corresponding public key can be used to decrypt. Because encryption and decryption use two different keys, this algorithm is called asymmetric encryption algorithm. The basic process of asymmetric encryption algorithm to realize confidential information exchange is: Party A generates a pair of keys and publishes one of them as a public key to other parties; Party B who obtains the public key uses the key to encrypt the confidential information and then send it to Party A; Party A will decrypt the encrypted information with another private key. On the other hand, Party A can use Party B's public key to sign the confidential information and then send it to Party B; Party B uses its own private key to verify the data. Party A can only use its private key to decrypt any information encrypted by its public key. Asymmetric encryption algorithm has better confidentiality, it eliminates the need for end users to exchange keys. The characteristics of asymmetric cryptosystem: the strength of the algorithm is complex, the security depends on the algorithm and the key, but because of the complexity of the algorithm, the speed of encryption and decryption is not as fast as that of symmetric encryption and decryption. There is only one key in symmetric cryptosystem, and it is not public. If you want to decrypt, you have to let the other party know the key. So to ensure its security is to ensure the security of the key, and asymmetric key system has two kinds of keys, one of which is public, so that it does not need to transmit the other party's key like symmetric password. So the security is much greater
1. A wants to send information to B. both a and B need to generate a pair of public key and private key for encryption and decryption
2. A's private key is confidential, and a's public key tells B; B's private key is confidential, and B's public key tells a
3. When a wants to send information to B, a encrypts the information with B's public key, because a knows B's public key
4. A sends this message to B (the message has been encrypted with B's public key)
5. After receiving this message, B decrypts the message of a with its private key. All other people who receive this message cannot decrypt it because only B has B's private key