Symmetric and asymmetric encryption

What is symmetric encryption technology?

Symmetric encryption uses symmetric encryption technology, which features that file encryption and decryption use the same key, that is, the encryption key can also be used as the decryption key. This method is called symmetric encryption in cryptography.AlgorithmSymmetric encryption algorithms are easy to use, have short keys, and are difficult to crack. Apart from Data Encryption Standard (DES), another symmetric key encryption system is the International Data Encryption Algorithm (IDEA ), it is better than DES encryption and has less requirements on computer functions. Idea encryption standards are used by PGP (pretty good privacy) systems.

Symmetric encryption algorithms have several problems in the e-commerce transaction process:

A secure channel is required for both parties to negotiate a common key during the first communication. Direct face-to-face negotiation may be unrealistic and difficult to implement. Therefore, both parties may need to negotiate through emails, phone calls, and other relatively insecure means;

The number of keys is difficult to manage. Because different keys are required for each partner, it is difficult to adapt to a large amount of information exchange in the open society;

Symmetric encryption algorithms generally do not provide information integrity identification. It cannot verify the identity of the sender and receiver;

The management and distribution of symmetric keys is a potentially dangerous and cumbersome process. Symmetric encryption is implemented based on mutual protection of secrets. The trade sides that adopt symmetric encryption technology must ensure that the same key is used and that the exchange of keys between them is secure and reliable, at the same time, you must also setProgram.

What is asymmetric encryption technology?

In 1976, US scholars dime and Henman proposed a new key exchange protocol to solve the problems of public information transfer and key management, allowing communication Parties to exchange information on insecure media, securely reach an agreement on the key, which is the "public key system ". Compared with symmetric encryption algorithms, this method is also called asymmetric encryption algorithms ".

Unlike symmetric encryption algorithms, asymmetric encryption algorithms require two keys: public key and private key ). A public key is a pair of private keys. If a public key is used to encrypt data, only the corresponding private key can be used for decryption. If a private key is used to encrypt data, only the corresponding public key can be decrypted. Because encryption and decryption use two different keys, this algorithm is called asymmetric encryption algorithm.

The basic process for asymmetric encryption algorithms to exchange confidential information is: Party A generates a pair of keys and discloses one of them as a public key to other Parties; if Party B obtains the public key, it encrypts the confidential information and sends it to Party A. Party A decrypts the encrypted information with another private key. Party A can only use its private key to decrypt any Information encrypted by its public key.

Asymmetric encryption algorithms have good confidentiality and eliminate the need for end users to exchange keys. However, encryption and decryption take a long time and are slow, it is not suitable for encrypting files, but only for encrypting a small amount of data.

Symmetric encryption and asymmetric encryption (private key and public key)

Vpnc published on 15:06:00 Symmetric encryption, or private keys (also known as regular encryption) are shared by both parties. The sender uses the key to encrypt plaintext into a secret when performing mathematical operations. The receiver uses the same key to restore the ciphertext to a plaintext. RSA RC4 Algorithm, Data Encryption Standard ( Des ), International Data Encryption Algorithm ( Idea ) And Skipjack Encryption technologies are symmetric encryption methods. Asymmetric encryption, or public keys. Communication Parties use two different keys. One is a private key that only the sender knows, and the other is a public key that anyone can obtain. Private keys and public keys are associated with each other in the encryption algorithm. One is used for data encryption and the other is used for data decryption. Public key encryption technology allows digital signature of information. The digital signature uses the private key of the sender to encrypt a part of the sent information. After receiving this information, the receiver decrypts the digital signature using the public key of the sender to verify the sender's identity. User Certificates can be stored in dial-up customers.PC, Or stored in an external smart card.In either way, if the user cannot provide user identification information without certain forms (PinNo. Or user name and password), you cannot access the certificate.

Symmetric encryption and asymmetric encryption

Software Shengjun (visitor)Comment on2006-10-18 21:44:00 in symmetric encryption (or single-key encryption, only one key is used to encrypt and decrypt information. Although single-key encryption is a simple process, both parties must completely trust each other and hold the backup of this key. However, reaching this level of trust is not as simple as you think. When both parties try to establish a trust relationship, a security breach may have occurred. First, the transmission of a key is an important issue. If it is intercepted, there will be no security for this key and related important information. Asymmetric encryption uses a pair of keys in the encryption process, instead of using a separate key instead of symmetric encryption. One key is used for encryption, and the other key is used for decryption. If a is used for encryption, B is used for decryption. If B is used for encryption, A is used for decryption. an important concept is that one key is used for public access in the key pair, and the other is used as a private key. The other half is called a public key, and the other half is the private key to be safely protected. One disadvantage of asymmetric encryption is that encryption is very slow because it requires a strong mathematical program. If a user needs asymmetric encryption, it may take several hours to get a small amount of information. Another name of asymmetric encryption is public key encryption. Although both the private key and public key are related to mathematics, it is very difficult and time-consuming to determine the value of the private key from the public key. For communication over the Internet, asymmetric encryption of key management is easy because public keys can be easily transmitted, and private keys must be carefully protected by users.

Public Key or asymmetric encryption
	(Public-Key or asypolicric cryptography)

public key cryptography provides a secure way for computer users to exchange information. The public key encryption standard is a standard developed by the RSA laboratory by security system developers around the world. Currently, PKCS is widely used, and some standard documents are part of formal or informal standards, including ANSI x9 documents, pkix, set, S/MIME, and SSL. Public key encryption is also called asypolicric encryption. It is based on the mathematical model developed by Diffie and Hellman. the public key encryption technology allows anyone to encrypt the information and send it to another user without prior key exchange. However, this process is not feasible between two people who know each other or belong to the same organization. To exchange sensitive data packets over the Internet during public key encryption, two types of key support are required: public key and private key. The Public Key is made public by its owner, and the private key must be kept confidential. To send a confidential message, the sender must use the recipient's public key to encrypt the data. Once encrypted, only the recipient can use its private key to decrypt the data. In other words, if a wants to send encrypted data to B, A uses B's public key to encrypt the data to be sent, B uses the corresponding private key to decrypt the encrypted data sent by. On the contrary, you can use your own private key to process data encrypted with a public key. However, this method is not very useful for encrypting sensitive packets because everyone can obtain the public key to decrypt the information. However, it can be applied to the following scenario: when a user wants to process data with his/her own private key, he/she can use the public key provided by the user to process the data, this provides the basis for "Digital Signature. PKI: Public Key Infrastructure is a system that provides public key creation and management based on the above basic concepts, supports efficient data encryption and key exchange processes.

Public Key or asymmetric encryption