In a public key cryptography, the HASH algorithm is 10

What are the two basic models of public key cryptography: what are the processes of the encryption model and the authentication model? Hello dear, encryption and authenticationFirst of all, we need to distinguish between the two basic concepts of encryption and authentication. Encryption is the encryption of data, so that even if illegal users obtain encrypted data, they cannot obtain the correct data content, so data encryption can protect data and prevent snooping attacks.

The focus is on the security of the data. Identity authentication is used to judge the authenticity of an identity, and after the identity is confirmed, the system can grant different permissions according to different identities. The focus is on the authenticity of the user.

The focus of the two is different. Public and private keysThe public and private keys are commonly known as asymmetric encryption, which is an improvement from the previous symmetric encryption method (using username and password). In modern cryptography, encryption and decryption use different keys (public keys), that is, asymmetric key cryptography, and each communicating party needs two keys, namely the public key and the private key, which can be encrypted and decrypted by each other.

This is mainly to ensure that the designed cryptographic algorithm is reliable and cannot be cracked casually, because the designed cryptographic algorithm always has to be used by people, and it must be widely used.

In a public-key cryptography, the encryption key (i.e., the public key) PK is public information, while the decryption key (i.e., the secret key) SK needs to be kept secret. Encryption algorithm E and decryption algorithm D are also public. Although the secret key SK is determined by the public key PK, the SK cannot be calculated based on the PK.

Public Cryptographic Algorithms:

The key used for encryption is different from the key used for decryption, and the decryption key cannot be computed from the encryption key (at least for a reasonably assumed long period of time). The reason why it is called the public key algorithm is because the encryption key can be made public, that is, strangers can encrypt information with the encryption key.

However, the information can only be decrypted with the corresponding decryption key. In these systems, the encryption key is called the public key (public key) and the decryption key is called the private key (private key). Private keys are sometimes referred to as secret keys.

To avoid confusion with symmetric algorithms, the name secret key is not used here.

The most well-known algorithm for the widespread use of public key infiltration cryptography is () Correct answer: a

Answer] :d This question is a test of the basic knowledge of encryption algorithms. Commonly used encryption algorithms are divided into single-key and double-key encryption systems according to the number of keys used, and guessing is also called private burning key and public key encryption algorithms.

ECC, DSA, and RSA are all public-key cryptography algorithms, and DES is a typical private-key cryptography system.

Classical encryption algorithms are divided into substitution algorithms and displacement shift methods.

1. Alternative algorithms.

The substitution algorithm replaces the letters of the plaintext with other letters or numbers or symbols. The most well-known alternative algorithm is the Caesar cipher. The principle of the Caesar cipher is very simple, it is actually a single letter substitution.

Example: Plaintext: abcdefghijklmnopq

Ciphertext: defghijklmnopqrst

2. Displacement and displacement method.

One of the most well-known types of ciphers that use the permutation-shift method is called the Virginia cipher. It replaces the cipher with a cyclical replacement based on a displacement shift.

In the Virginia cipher, the encryption key is an arbitrarily specified string. The encryption key characters are applied to the plaintext information characters one by one. The length of the plaintext information is often greater than the length of the key string, and each character of the plaintext needs to have a corresponding key character, so the key needs to be looped until each character in the plaintext corresponds to a key character.

Other common encryption algorithms.

1. The DES algorithm is a symmetric cryptosystem in the cryptosystem, which changes the 64-bit plaintext input block into a 64-bit ciphertext output block, and the key it uses is also 64-bit.

DES is a symmetric algorithm based on DES, which encrypts a piece of data three times with three different keys, which is stronger.

3. RC2 and RC4 are symmetric algorithms, which encrypt a large amount of data with a variable-length key, which is faster than DES.

4. The IDEA algorithm is developed on the basis of the DES algorithm, which is implemented as an iterative block cipher, using a 128-bit key and 8 loops.

5. RSA is invented by RSA company, which is a public key algorithm that supports variable-length keys, and the length of the file block that needs to be encrypted is also variable, asymmetric.

6. DSA, or digital signature algorithm, is a standard DSS (digital signature standard), which is not strictly speaking, an encryption algorithm.

7. AES is an advanced encryption standard symmetric algorithm, which is the next generation of encryption algorithm standard, with fast speed and high security level, and an implementation of AES standard in the 21st century is Rijndael algorithm.