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What is the difference between a symmetric key and an asymmetric key? In view of this problem, this article introduces the corresponding analysis and answers in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.

The difference between symmetric key and asymmetric key is that symmetric key encryption and decryption use the same key, asymmetric key encryption and decryption use no key; symmetric key algorithm encryption is simple, encryption and decryption speed is fast, but asymmetric key encryption and decryption speed is slow.

Differences in keys used in encryption and decryption

From the above description of the symmetric key algorithm and the asymmetric key algorithm, we can see that the symmetric key uses the same key for encryption and decryption, or the decryption key can be easily derived from the encryption key; while the asymmetric key algorithm uses different keys for encryption and decryption, one of them is difficult to derive the other key.

Algorithmic differences:

① symmetric key algorithm uses packet encryption technology, that is, the plaintext to be processed is grouped according to a fixed length, and the packet is iterated several times with the key, and finally the ciphertext is obtained. Similarly, under the control of a fixed-length key, the plaintext is obtained by iterative decoding several times in the unit of a packet. The asymmetric key algorithm uses a special mathematical function, one-way trapdoor function (one way trapdoor function), that is, it is easy to evaluate from one direction, but its reverse calculation is very difficult, or it is not feasible. When encrypting, the plaintext is encrypted and transformed by the public key to get the ciphertext. When decrypting the ciphertext, the private key is used to decrypt the ciphertext to get the plaintext.

② symmetric key algorithm has the characteristics of simple encryption, fast encryption and decryption speed, short key, long development history and so on. Asymmetric key algorithm has the characteristics of slow encryption and decryption speed, large key size and short development history.

The difference of key Management Security

Because the symmetric key algorithm is public, its confidentiality depends on the secrecy of the key. Because the keys used by both encryption and decryption are the same, it is difficult to distribute and replace the keys. Because the key has been distributed in advance, the asymmetric key algorithm does not need to transmit the key in the process of communication, so the security is greatly improved, and the problem of key management is solved.

Security.

Because the symmetric key algorithm is public, its security depends on the length of the packet and the length of the key. the common attack methods include exhaustive key search, dictionary attack, look-up table attack, differential cryptanalysis and linear cryptanalysis. the most effective one is differential cryptanalysis, which recovers some key bits by analyzing the influence of plaintext on the difference of ciphertext pairs. The security of asymmetric key algorithm is based on the difficulty of one-way function, such as elliptic curve cryptography algorithm, which is considered by many cryptographic experts to be exponential. From the known algorithms, the security of 160bit elliptic curve cryptography algorithm is equivalent to that of 1024bit RSA algorithm.

The answer to the question about the difference between symmetric key and asymmetric key is shared here. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel for more related knowledge.

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