Shulou(Shulou.com)06/02 Report--

256bit encryption is an important part of SSL certificates. Typically, the encryption algorithm used in SSL refers to asymmetric encryption, even with two completely different but perfectly matched pairs of keys-the public key and the private key. When using asymmetric encryption algorithm to encrypt files, the process of encryption and decryption of plaintext can be completed only by using a matching pair of public and private keys.

In practical application, data encryption is not accomplished by asymmetric encryption, but symmetrical encryption. Public / private key pairs are used for authentication only. When the client and server meet for the first time, they both need to verify each other's identity. Authentication is done through public / private key pairs, which is the role of asymmetric encryption. Once the authentication is complete, the TLS handshake is performed, and the actual encryption begins and is done through symmetric encryption.

What is 256-bit encryption?

256-bit encryption refers to the key length of symmetric encryption technology. That is, the key consists of 256 binaries (0 and 1) and 256 random combinations.

For example, suppose you have a 2-digit key. Therefore, it will have 22 million 4 values, that is, 00B01JI 10 and 11. As a result, a 256-bit key can have 2256 possible combinations.

What is the security of 256-bit encryption?

"how secure is 256 bit encryption?"is 256 bit encryption sufficient?" These are the two most common problems in the encryption level. And now our answer is: more than enough. The reason for giving this affirmative answer is because of the so-called "mathematics".

If you want to crack an encryption key, there is only one way, and that is "brute force", which is simply trial and error. Therefore, if the key length is 256 bits, there will be 2256 possible combinations, and before coming to a conclusion, the hacker must try most of the 2255 possible combinations (typically, it takes about 50% of the keys to get the correct combination).

2 256 may look like a normal number, but don't underestimate its power. 256 bits will have a possible combination of 1157920892373161954235709850086879078532699846656405640397584007913129639936 (78 digits). Is there still a supercomputer on earth that can be cracked?

Even with the world's fastest supercomputer, the Tianhe-2 (MilkyWay-2), it would take millions of years to crack 256-bit encryption.

So do you still need to doubt the security of 256-bit encryption?

The difference between https and http

First, the https agreement needs to apply for a certificate to ca. Generally, there are few free certificates and a fee is required. Https encrypted website is not only secure, but also reflects the company's formal and has a certain strength.

Second, http is a hypertext transmission protocol, information is plaintext transmission, and https is a secure ssl encryption transmission protocol.

Third, http and https use completely different connection methods and different ports. The former is 80 and the latter is 443.

Fourth, the connection of http is very simple and stateless; HTTPS protocol is a network protocol built by SSL+HTTP protocol for encrypted transmission and identity authentication, which is more secure than http protocol.

Fifth, the investment in http website construction is less, while the investment in https encrypted website is much larger. What are the main services provided by the SSL protocol?

1) authenticate users and servers to ensure that data is sent to the correct clients and servers

2) encrypt data to prevent data from being stolen

3) maintain the integrity of the data to ensure that the data will not be changed during transmission.

Https (full name: Hypertext Transfer Protocol over Secure Socket Layer) is a security-oriented HTTP channel, which is simply the secure version of HTTP. That is, the SSL layer is added under Hhttp, and the security basis of https is SSL, so the details of encryption need SSL. It is developed by Netscape and built into its browser to compress and decompress the data and return the results sent back on the network. Https actually applies Netscape's secure Sockets layer (SSL) as a sublayer of the http application layer. (https uses port 443 instead of port 80 to communicate with TCP/IP as http does. SSL uses 40-bit keywords as the RC4 stream encryption algorithm, which is appropriate for the encryption of business information. Https and SSL support the use of X.509 digital authentication, and users can confirm who the sender is if necessary.

In other words, its main role can be divided into two kinds: one is to establish an information security channel to ensure the security of data transmission; the other is to confirm the authenticity of the website. SSL protocol is located between TCP/IP protocol and various application layer protocols, which provides security support for data communication. SSL protocol can be divided into two layers: SSL recording Protocol (SSL Record Protocol): it is based on reliable transport protocols (such as TCP) and provides support for high-level protocols such as data encapsulation, compression, encryption and other basic functions. SSL handshake Protocol (SSL HandshakeProtocol): it is based on the SSL recording protocol and is used for identity authentication, negotiation of encryption algorithms, exchange of encryption keys, etc., before the actual data transmission begins.

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