What is the main difference between public key encryption and traditional encryption systems?

Main difference: A public key is used to encrypt data, and a private key is used to decrypt data. Public key encryption refers to an encryption method consisting of a corresponding pair of unique keys (public key and private key); the public key and the private key are a pair. If the public key is used to encrypt data, It can only be decrypted with the corresponding private key.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

The main difference between public key encryption and traditional encryption systems is that a public key is used to encrypt data, and a private key is used to decrypt data.

Public key encryption, also called asymmetric (key) encryption (public key encryption), refers to a corresponding pair of unique keys (i.e., public key and private key). encryption method. It solves the problem of key issuance and management and is the core of commercial cryptography. In the public key encryption system, the private key is not disclosed, but the public key is disclosed.

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, then only the corresponding private key can be used to decrypt the data. Only the corresponding public key can be decrypted. Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm.

The basic process of asymmetric encryption algorithm to realize the exchange of confidential information is: Party A generates a pair of keys and discloses one of them as a public key to other parties; Party B who obtains the public key uses the The key encrypts the confidential information and then sends it to Party A; Party A then uses another private key kept by itself to decrypt the encrypted information. Party A can only use its private key to decrypt any information encrypted by its public key.

Characteristics of the public key cryptography system:

The public key cryptography system is an asymmetric key. The advantage is that the calculation speed is fast and the key is easy to generate.

(1) High confidentiality strength

The theoretical basis is based on the difficulty of factoring large prime numbers in number theory. When n is greater than 2048 bits, the current algorithm cannot decipher RSA within an effective time .

(2) Key distribution and management are simple

In the RSA system, the encryption key and the decryption key are different and separated. The encryption key can be made public, and the decryption key is kept secretly by the user. The amount of secretly kept keys is reduced, which makes key distribution more convenient and facilitates key management.

(3) Digital signatures are easy to implement

In the RSA system, only the recipient uses its own decryption key to sign the plain text, and anyone else can use the public key to sign the signed text. Verified, but cannot be faked.

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